Little or no vacuum

[The_Handier_Man1]

From: HeavyHaulTrucker  (Original Message)
Sent: 11/29/2004 10:59 PM

HELP!!!

Recently, my 440-3 with ThermoQuad (with only 52,000 miles) has begun running badly (like crap, actually).  Here are the symptoms:
Lack of any power in drive;
Except for low vacuum, it runs great in Park;
Vacuum runs at about 13 inches at idle in Park;
Vacuum drops to about 9 inches when I put it into Drive;
Vacuum drops to less than 4 inches during any acceleration in Drive;
At idle in Park, capping off the distributor vacuum advancc line, dashpot line, or cruise control vacuum line produces only a small change in engine RPM;
If I give it too much gas in first gear, it begins popping in the carb's primary until I let off of the gas a bit;
When it shifts to second, it starts popping in the carb's primary until I let off of the gas a bit;
It will accelerate gradually up to about 50 mph before it will shift to third;
When it finally shifts to third, it will not hold speed even with the pedal almost all the way to the floor;
When I am in third, I can "snap" the accelerator down and downshift, and I can both feel and hear the secondaries kick in -- it accelerates like a race horse then, until it shifts back to third.

Here is everything that has been done to try to correct this problem:
The carb has been re-built again;
The idle mixture jets have been re-adjusted as specified on the engine's valve cover (my decal is still readable!);
The primary mixture tree has been re-adjusted as specified in the service manual;
The carb base adapter and both gaskets have been replaced;
All vacuum hoses have been replaced, even the one through the doghouse for the vacuum guage;
The PCV Valve has been replaced;
The brake booster check valve has been replaced;
The in-line fuel filter at the carb (this is the only one I use) has been replaced;
New plug wires and coil wire were installed;
The plugs are almost new Bosch Platinum plugs, gapped at .035;
The ignition module was replaced about 3 weeks ago;
I checked for -- and did not find any -- vacuum leaks using a propane torch held near the carb base, throttle shafts, as well as each vacuum connection and fitting;
The engine has been re-timed to 8 BTDC base timing as specified on my valve cover decal;
The transmission fluid has been completely drained & replaced -- a new trans filter was also installed;
Can anyone figure out what the heck is going on???  I am at my wit's end with this, and have run out of ideas -- I don't see what else could be the cause. 

Oh, BTW Sea Hag, you are right about an electic fuel pump ruining the mechanical fuel pump's diaphragm -- I had to change my mechanical pump last week, and I ended up disconnecting & bypassing the electric pump in order to get it to run close to right.  I think that the electric pump either went out or is going out.  With a new mechanical pump, though, it doesn't take but a few seconds more cranking to get it started in the mornings (it is below 30 degrees here now) even without the electric pump -- I don't think I will bother replacing the electric.

John



From: cooneytunes
Sent: 11/29/2004 11:33 PM

John, had a 79 Ford P/U that did simialr. the only way I could get it to run right was to advance the timing. It was wrong according to the specks, but, like yours, it would idle like a show room car, as soon as it was under a load, it ran like a piece of crap, doing exactly what yours is doing. Did very much the same you did as far as trying to correct, and nothing worked. The more the load the worse it ran. Had to just turn the distributor till it was a little advanced. That solved the problem, ran great after that. In fact the guy I sold it too,(in 1990) still has it, and it still runs great, but the timing is always got to be advanced more than the specks show....... It nearly
drove him crazy till I met him one day, about 3 mos after I sold it to him, He did a complete tune and carb change, reset the timing to specs.... and trouble started in River City,  told him to try just advancing timing a bit.  It solved the problem again. Why? I don't know.... Hope that's all it is with yours.
Timmy



From: Enigma960080
Sent: 11/30/2004 7:39 AM

Off the top of my head, it  sounds like a  valve timing issue.  I would  check for slack in the timing chain  by pulling the distributor cap, marking the position of the rotor  then turn the crank by hand  to see how far it turns before the  rotor moves.  I am not sure  what the spec  should be, but in my mind, anything  more than a few degrees is a few degrees too much



From: Derrek
Sent: 11/30/2004 8:37 AM

Timing chain slack test:

http://www.misterfixit.com/chanslop.htm



From: DaveVa78Chieftain
Sent: 11/30/2004 4:39 PM

Just went through some of this type of thing myself.  Turned out to be (1) a burnt plug wire under the spark plug boot and (2) the cruise control circuit had a vacume leak.
First, does is it seem to be missing at idle?  If so, which cylinders?  Cruise control module vacume leak will cause #6 and #7 cylinders to run lean.  Is the EGR valve stuck open or has carbon built up on it?  If missing, you may be able to associate a vacume leak by following the intake runners.  Thats how I figured out the cruise control problem.  Again, the hoses were new but the cruise control module itself was bad.  Is the distributor vacume advance diaphragm ok?
77 and later year 440-3 engines run extremly lean per design.  They also have a lower compression ratio than earlier years.  Vacume leaks result in an even leaner mixture that can ignite in the intake manifold.  Thats what was happening to me.  The exhaust crossover ports in the intake manifold have a lot to do with that.  The 8 degree before timing setting should work fine.  I am running mine at 7 because of preignition under load.
Thermo quads are famous for vacume leaking at the carb base plate (manifold heat dries the gasket out).  The hold down bolts can vibrate loose also.  Have you done a compression test to see if you have leaking intake valves?  At 52,000 miles, your timing chain may or may not be a problem.  I have seen references that they can become questionable at 40,000 miles.  Do the the check posted above to check it.  I have almost 100,000 and mine is still ok.
For reference, my 77 440-3 (with thermoquad) runs 17 lbs of vacume in park.  In drive it is 15 lbs.  Normal flat road cruise vacume is 10 - 12 lbs.  I was having the problems you describe when the engine load dropped the vacume to around 6 lbs.
As I said, my problems were centered around vacume leaks.  I was fortunant that the lean cylinders were also missing at idle.  Becasue you typically only hear about old vacume hoses casuing problems, I did not think past that until I read an article where the owner asked the mechanic what was wrong with his engine.  Well, when the mechanic said your right front headlight cover controller was bad the guy thought he was being feed a story.  The mechanic explained to him that when the weather gets colder the air gets denser resulting in an engine running even leaner.  An existing problem may not raise it's head in warmer climes however it appears when the air gets colder.  In this case, the headlight cover controller itself had a leak which caused the #1 cylinder to run lean resulting in a rough idle.  In my case, the cruise control tap was on the intake runner for #6 and #7 cylinders ergo they were missing at idle.  Under load, the vacume leak resulted in a very lean mixture on those cylinders in the intake manifold such that the heat from the valves or piston hot spots caused the very lean mixture to ignite in the manifold under load.
Step back and take stock of things.  The problem maybe more obvious than it appears.  The engine should run pretty damn smooth at park idle.  Even in drive idle it should run smooth.

Good luck - Dave



From: DaveVa78Chieftain
Sent: 11/30/2004 4:50 PM

Just noticed you said break booster check valve.  Any problems (vacume leaks) in the break booster circuit?
In order to check a lot of these external devices, a simple hand vacume pump from the auto supply store is all thats needed.  It is supplies the vacume to a component instead of the engine when troubleshooting.  Runs about $25 but can be used to check a whole lot of things.  Newer cars are a maze of vacume controls that can be potential problems.

Dave



From: HeavyHaulTrucker
Sent: 11/30/2004 11:39 PM

Rich, how is that possible?  Everything I have read on the TF727 adamnantly states that the converter can only be installed one way (because of the bolt pattern).  When your engine was removed, did they have the front cover & timing chain off?  Could it be possible that they reassembled it with the distributor a couple of degrees off?  That is what it sounds like... as far as I know, the torque converter has nothing to do with the engine timing.

As far as timing, my engine will run pretty good when I move the distributor so that the timing light fires when the dampener mark is at the second line down from the "0" ( I assume that this is 4 degrees BTDC?) -- anything less than that, and I get severe detonation under load.  The below drawing illustrates where my timing is set at right now... the full length "cut" on the dampener lines up with the arrow.  When I timed it, I took a black "Sharpie" marker and highlighted the edges of the long cut in the dampener, and marked the line on the scale corresponding with 8; I then moved the distributor until they lined up, then had a helper lock down the distributor bolt.

I assume that this is correct?  What is the large, U-shaped notch on the top?  Is that Top Dead Center, or is that where the timing should actually be?  I have zero experience with Dodge engines before I bought this Winnie -- wouldn't it be a kick in the teeth if I have it timed over 20 degrees off???!!

John



From: Sea Hag
Sent: 12/1/2004 8:29 AM

John , the drawing is in the correct position for 8 degrees BTC . Not sure what the horse shoe is for . There is a pick of the actual scale from my engine , You should be able to find it searching timming dicussions .
    The flywheel or torque converter has a timming mark on it also , there is an access hole in the top of the bell housing , below the ignition modual mounting plate . I think that is what Rich was refering to .
   It may sound a little wierd but I was chassing a miss down last summer . I thought it had to do with timming or wireing , but ended up being a leak in the fuel line , just before the tank switch . It was sucking air and causing some of the same problems your haveing ( lack of power , missing , poping , ect . ) . It's worth a quick check . Sea Hag



From: DaveVa78Chieftain
Sent: 12/1/2004 10:45 AM

John,
As far as vacume leaks go, I would take the view that any thing could be the culprit.  You simply have to do a systematic check of the components.  I can only say I became a believer of how they can affect the engine after going through that simular problem with mine a month ago.  I also know that the later model engines were tuned at the factory very lean.  Anything that leans the mixture further on any one or all cylinders is going to create problems.  Something else I thought of is when you rebuilt the carb, did you by chance disturb the setting of the itty bitty screw that adjusts the primary fuel metering rod height?  That little devil contols fuel/air mixture by adjusting the position of the fuel metering rods that move in and out of the main jets.  It is attached to a piston that is operated in 2 ways.   First, there is a cam lever under the piston that is operated by the primary throttle shaft.  The cam mechanically raises and lowers the piston therby adjusting the primary fuel metering rods.  The piston is held against the cam by manifold vacume.   The 2nd way it is operated is by vacume.  When manifold vacume goes below 6.5 (may be as low as 3 or 4) the spring under the piston pushes the piston up thereby pulling the metering rods further out of the main jets.  This acts as the power circuit in other carbs.  Richens the primary mixture even more as a prelude (transition) to the rear throttle barrels opening up.  Being tied to the primary side it is not dependent on the secondary side.  Actually, the vacume side of this gets a lot of use.  It engages anytime you need extra power (starting form a dead stop, going up a hill, etc).  Under heavy load (very low manifold vacume), the spring under the piston pushes the piston off of the mechanical cam underneath the piston (metering rods go up resulting in a richer mixture).  Being vacume controlled, just watching manifold vacume while driving you can see that it comes into play a lot.  Some form of power circuit is there in all carbs for this purpose.  Now, if the adjustment screw on top of the piston has been disturbed (listed as a factory only setting because of emissions control effects), if the piston is binding up (carbon build up) not allowing the metering rods to come out of the main jets at low vacume, or the spring under the piston has become weak, then the engine would run far to lean.  You can see the rods move up and down when looking at the carb.  With the engine off, the metering rods will be pushed all the way out of the main jets by the spring under the piston.  You will see the rods pulled into the jets by engine vacume when you start the engine.  I seem to recall about 1/2 inch of travel for them.  With the engine off, you can lightly push down on the metering rod connector bracket and feel the spring resistance.  Again, that itty bitty screw in the middle of the fuel metering rod bracket controls the height of the metering rods in the main jets thereby controling how much fuel (air/fuel mixture) is allowed to pass through the main jets.  I did not read the section do not disturb the metering rod adjustment screw when I rebuilt my carb so I have had to use seat of the pants tweaking to find the best setting for it.   Needless to say, I know all this because I had to figure out how my mistake affected things.
At idle, there should be little or no vacume at the distributor vacume advance port (no advance).  This is because the vacume tap off port for this circuit in the primary throttle bore is above the throttle plates.  Additionally, there is no vacume at this port under full throttle (no advance).  Again, that is due to low mainifold vacume.   Even during normal operation how much vacume advance you see depends on overall engine load.  The higher the load, the less manifold vacume ergo less distributor advance vacume (less or, more typically, no advance).  Actually, if you hook up a gauge and monitor that circuit you will find that vacume advance only gets fully engaged once you have achieved a steady speed.  Start going up a hill (engine load increase) and it drops off fast.
Last but not least, I am sure the lean burn emission setup also attributes to why we have exhaust manifold headaches.   The leaner an engine runs, the hotter the exhaust temps.  Hotter temps result in more expansion/contraction (thermal stress) of the exhaust manifolds.
My timing marks on the timing cover look exactly as pictured above.  I am running at 7 degrees to avoid pre-ignition.  I remove the radiator overflow tank in order to get a good view of the timing marks.  I have that odd notch too and I have no idea what it is for.

Dave



From: HeavyHaulTrucker
Sent: 11/30/2004 11:39 PM

Rich, how is that possible?  Everything I have read on the TF727 adamnantly states that the converter can only be installed one way (because of the bolt pattern).  When your engine was removed, did they have the front cover & timing chain off?  Could it be possible that they reassembled it with the distributor a couple of degrees off?  That is what it sounds like... as far as I know, the torque converter has nothing to do with the engine timing.

As far as timing, my engine will run pretty good when I move the distributor so that the timing light fires when the dampener mark is at the second line down from the "0" ( I assume that this is 4 degrees BTDC?) -- anything less than that, and I get severe detonation under load.  The below drawing illustrates where my timing is set at right now... the full length "cut" on the dampener lines up with the arrow.  When I timed it, I took a black "Sharpie" marker and highlighted the edges of the long cut in the dampener, and marked the line on the scale corresponding with 8; I then moved the distributor until they lined up, then had a helper lock down the distributor bolt.

I assume that this is correct?  What is the large, U-shaped notch on the top?  Is that Top Dead Center, or is that where the timing should actually be?  I have zero experience with Dodge engines before I bought this Winnie -- wouldn't it be a kick in the teeth if I have it timed over 20 degrees off???!!

John



From: Sea Hag
Sent: 12/1/2004 8:29 AM

John , the drawing is in the correct position for 8 degrees BTC . Not sure what the horse shoe is for . There is a pick of the actual scale from my engine , You should be able to find it searching timming dicussions .
    The flywheel or torque converter has a timming mark on it also , there is an access hole in the top of the bell housing , below the ignition modual mounting plate . I think that is what Rich was refering to .
   It may sound a little wierd but I was chassing a miss down last summer . I thought it had to do with timming or wireing , but ended up being a leak in the fuel line , just before the tank switch . It was sucking air and causing some of the same problems your haveing ( lack of power , missing , poping , ect . ) . It's worth a quick check . Sea Hag 



From: DaveVa78Chieftain
Sent: 12/1/2004 10:45 AM

John,
As far as vacume leaks go, I would take the view that any thing could be the culprit.  You simply have to do a systematic check of the components.  I can only say I became a believer of how they can affect the engine after going through that simular problem with mine a month ago.  I also know that the later model engines were tuned at the factory very lean.  Anything that leans the mixture further on any one or all cylinders is going to create problems.  Something else I thought of is when you rebuilt the carb, did you by chance disturb the setting of the itty bitty screw that adjusts the primary fuel metering rod height?  That little devil contols fuel/air mixture by adjusting the position of the fuel metering rods that move in and out of the main jets.  It is attached to a piston that is operated in 2 ways.   First, there is a cam lever under the piston that is operated by the primary throttle shaft.  The cam mechanically raises and lowers the piston therby adjusting the primary fuel metering rods.  The piston is held against the cam by manifold vacume.   The 2nd way it is operated is by vacume.  When manifold vacume goes below 6.5 (may be as low as 3 or 4) the spring under the piston pushes the piston up thereby pulling the metering rods further out of the main jets.  This acts as the power circuit in other carbs.  Richens the primary mixture even more as a prelude (transition) to the rear throttle barrels opening up.  Being tied to the primary side it is not dependent on the secondary side.  Actually, the vacume side of this gets a lot of use.  It engages anytime you need extra power (starting form a dead stop, going up a hill, etc).  Under heavy load (very low manifold vacume), the spring under the piston pushes the piston off of the mechanical cam underneath the piston (metering rods go up resulting in a richer mixture).  Being vacume controlled, just watching manifold vacume while driving you can see that it comes into play a lot.  Some form of power circuit is there in all carbs for this purpose.  Now, if the adjustment screw on top of the piston has been disturbed (listed as a factory only setting because of emissions control effects), if the piston is binding up (carbon build up) not allowing the metering rods to come out of the main jets at low vacume, or the spring under the piston has become weak, then the engine would run far to lean.  You can see the rods move up and down when looking at the carb.  With the engine off, the metering rods will be pushed all the way out of the main jets by the spring under the piston.  You will see the rods pulled into the jets by engine vacume when you start the engine.  I seem to recall about 1/2 inch of travel for them.  With the engine off, you can lightly push down on the metering rod connector bracket and feel the spring resistance.  Again, that itty bitty screw in the middle of the fuel metering rod bracket controls the height of the metering rods in the main jets thereby controling how much fuel (air/fuel mixture) is allowed to pass through the main jets.  I did not read the section do not disturb the metering rod adjustment screw when I rebuilt my carb so I have had to use seat of the pants tweaking to find the best setting for it.   Needless to say, I know all this because I had to figure out how my mistake affected things.
At idle, there should be little or no vacume at the distributor vacume advance port (no advance).  This is because the vacume tap off port for this circuit in the primary throttle bore is above the throttle plates.  Additionally, there is no vacume at this port under full throttle (no advance).  Again, that is due to low mainifold vacume.   Even during normal operation how much vacume advance you see depends on overall engine load.  The higher the load, the less manifold vacume ergo less distributor advance vacume (less or, more typically, no advance).  Actually, if you hook up a gauge and monitor that circuit you will find that vacume advance only gets fully engaged once you have achieved a steady speed.  Start going up a hill (engine load increase) and it drops off fast.
Last but not least, I am sure the lean burn emission setup also attributes to why we have exhaust manifold headaches.   The leaner an engine runs, the hotter the exhaust temps.  Hotter temps result in more expansion/contraction (thermal stress) of the exhaust manifolds.
My timing marks on the timing cover look exactly as pictured above.  I am running at 7 degrees to avoid pre-ignition.  I remove the radiator overflow tank in order to get a good view of the timing marks.  I have that odd notch too and I have no idea what it is for.



From: denison
Sent: 12/1/2004 1:29 PM

You describe a mix of some classic symptoms of lean running, or weak spark, or incorrect timing or fouled plugs or poor compresssion; but not all of them. It’s the mix that is mysterious. So in addition to all the other advice.........
Throttle plate not completely closing inside the distributor?
Cruise circuit in the carburetor not percolating air into the fuel before it gets to the venturis? (Your Carter might not even work this way.)
Carburetor accelerator pump not working?
Water/oil inside distributor cap or on the rotor, or cracks on the rotors base?
Rotor having its contact spring broken off the top?
Rotor that can turn on the end of the distributor shaft- so it wouldn’t be pointing close enough to the correct terminal?
High voltage wires not fully seated in top of distributor and ignition coil?
Distributor cap not seated squarely onto top of distributor?
Sticking centrifugal advance in distributor?
Vacuum leak from a torn diaphram in one of the hydrovac boosters?
Could the dampener have skidded around on the hub of the crankshaft pulley, putting the timing slot in the wrong place?
You can time the ignition it by setting it for the highest vacuum, which I think would be advanced a little too far, then retarding it after test drives until it just stops pinging. Do the initial timing with the vacuum advance disconnected and capped off.
I assume you have the electronic ignition, or I would have expected that the points were worn too close together. But since I think you do you have electronic ignition, make sure the pickup assembly inside the distributor is not being scraped by the reluctor collar on the distributor shaft. Wiggle any connector between that pickup assembly and the ignition module at the back of the motor.
The spark should be a light blue and able to jump at least 1/4 inch, if not 3/8ths inch, at an idle, or you have weak spark.
Fouled spark plugs?
You don’t want to have both the resistance type spark plug wires and the resistance type spark plugs.
Are the two resistances in the dual ignition resistor connected as they should be



From: denison
Sent: 12/1/2004 1:35 PM

I meant to say that the secondary throats throttle plate has to be completely closing inside the carburetor. Sorry...



From: HeavyHaulTrucker
Sent: 12/1/2004 9:50 PM

Well, I think that I cured the biggest vacuum leak of all -- I got rid of the ThermoQuad this afternoon.  I am the proud owner of a brand spankin' new Edelbrock 1407 750 cfm Performer carburetor -- it cost me $239.93 at AutoZone.  And my initial tuning of it has yielded a marked improvement of the condition!  It still popped a little, but not enough to kill the engine like the old TQ used to do; I suspected that my timing was a little off, and advanced it a bit.  I was already on my levellers, so I will test it tomorrow with the new timing setting.

When removing the old TQ, I discovered that the primaries were totally flooded -- from underneath!  When I picked the old carb up off of the manifold, it was dripping fuel -- but the top of the throttle plates were bone dry.  I suspect a crack in the phenolic body, but I didn't bother to check -- I gave the old TQ to one of the guys there at AutoZone who said that he wants to use it to learn how to rebuild one.

It now will hold speed in third gear -- in fact, I can even gradually accelerate, even.  This was on my "home-bound run" back to the Flying J from AutoZone; with the change in timing I hope that I will be able to do a faster acceleration in third gear.  The cruise control held it at 65 after I got on the interstate, so I doubt that there is a vacuum leak there.

The dash mounted vacuum gauge is toast.  No matter what I do, it will now only read zero to 5 inches of vacuum.  I think that the mechanism used inside has sprung a leak; I have the hose disconnected and capped for now, until I can get another one.  Sunpro makes one identical (Model #CP7978, MSRP $23.99) to it that I will be having AutoZone order for me tomorrow.

I did not have enough money to buy the Edelbrock Chrysler Throttle Linkage Kit, so I rigged up my own setup.  It works great.  A picture of it is below for anyone who wants to duplicate it on their own carb replacement.  I also used the old choke linkage, but cut it off as needed -- then I bent it to go through the choke lever, and secured it with the snap clip from the old carb.

For those wondering how I add drawings like this to my messages, I just use MS Paint to draw them and save them to a GIF image file.  I then insert them into my post by using the "Insert Picture" icon on the editor toolbar.

I think that the Edelbrock carb went a long way towards curing this problem.  There was a drastic improvement in the popping, and I believe that the vacuum has come up based on the firmness of my brake booster feel.  I will check the results of my timing change tomorrow, and I will let you all know what happens.

John



From: Derrek
Sent: 12/2/2004 7:15 AM

John,

Thanks for the info on the drawings. But, I am left with another question.....Where can I get MS paint software??  Doing a Google search return many tutorials on how to use the software, but nowhere to download or purchase it. I tried a search of Bestbuy.com and still nothing. I then checked Ebay and still nothing...... I thought that you could find everything on Ebay...!!

Derrek



From: denison
Sent: 12/2/2004 7:21 AM

As far as I know, MSPaint software comes with the normal windows operating system installation.  If you have any version of a windows OS, do a file search for mspaint.exe on your disk.   Or for msp*.* for that matter.



From: Derrek
Sent: 12/2/2004 8:41 AM

Thanks Denison

I found it! I thought maybe is was part of Windows, but I looked under programs rather than doing a file search. Thanks again!

Derrek



From: HeavyHaulTrucker
Sent: 12/3/2004 1:27 AM

Well, here are the net results of replacing the carb:

The engine still "pops" (is this called detonation?) at 1200 to 1500 rpm  with heavy acceleration.  Once it gets over this hump, it still pops at the first/ second gear shift right after the shift.  None of the pops are anywhere near as bad as they were with the TQ, but they still suck for drivability.  Again, with this carb, wide open throttle hauls butt.

I have again re-timed the base timing, re-gapped the pickup coil (.006 inch).  After settng the base timing, I re-connected the vacuum line and had a helper run the engine up to 2500 rpm; it held about 30 to 35 degrees total timing.  I have ordered the new vacuum gauge, but it won't be in for a couple of days.  I wonder if this could be a transmission problem?  It is worst around shift points; in third gear, it accelerates without a complaint and will hold 65 mph.  Low speed/ high throttle operation is still problematic, though.

Could the torque converter be going out, thereby causing this problem?  When I changed the fluid and filter in the tranny, I noticed a very small amount of metal shavings and black soot-like material near the driver's side front corner of the filter & pan.

John



From: denison
Sent: 12/3/2004 1:46 AM

I dont think you have to worry about the black soot like material in your tranny, unless it covered the entire bottom of the pan in a gummy layer. The small amount in one corner is probably the normal shedding from the clutch frictional surfaces. The small amount of metal shavings might well result from putting it in park when it wasnt totally stopped -just metal cracked off the ends of the parking pawl or its mating toothed gear.
Pinging is a high pitched clinking, like someone dropping forks into the cutlery drawer in the kitchen. It wont be very loud, barely audible. What I call popping is a minor backfire, coming up through the carburetor. With the air cleaner and engine cover in-place it wouldnt be very loud either. With the air cleaner and engine cover off, it could be as loud a someone popping an air filled paper sack.
I cant imagine the torque converter would be causing the engine problem - but then I have never experienced a torque converter problem.



From: HeavyHaulTrucker
Sent: 12/3/2004 9:39 PM

Well, it looks like the distributor may be the culprit -- actually, the springs in the mechanical advance.  I broke down today and took it over to a local RV garage that came highly recommended.  After listening to my detailed account of what the problem is and what has been done so far, the mechanic gave me a no-money educated guess.

He said that, since the rest of the ignition system & carburetion system are new and that the popping happens at just ONE rpm (1500 rpm) that it sounds like the mechanical advance unit is flinging the weights out early and providing too much advance at the wrong time.  He reminded me that -- even though the counterweight springs have not received much use during the 53,400 miles -- they have been under tension for the past 27 1/2 years.  They have probably stretched just enough so that -- even though they do fine under 1500 rpm -- they allow the counterweights to fly out early and provide too much advance.  He also said that it could also be that the weights could be sticking at a certain point and not providing enough advance; when I coax it above that rpm, the vacuum advance kicks in and provides the needed advance or the centrifugal force increases enough to free the weights from their sticky spot allowing them to "catch up".

He pointed me towards Spectre Automotive products.  They make a distributor curve kit for the GM HEI ignition that is available at Auto Zone.  He says the springs in this kit are identical to the ones in the Dodge distributor, even though the weights are different.  He suggested, since I am comfortable taking the distributor apart myself, that I replace the springs and clean/ re-grease the spring guides and see if that helps.  He suggested the silver-colored (middle curve) springs as a start.  So I bought the kit at Auto Zone for $7.99 and I will tackle this tomorrow morning.

As an aside, I want to thank whoever it was who mentioned "Sea Foam" in another topic.  I found it at Auto Zone tonight and used it -- though I was a little skeptical about pouring it down the carburetor throat with the engine running.  I also poured it in the tanks, and I dumped a pint in the oil -- hey, i'll try anything at this point!!  Man, did that stuff work!  The 440 idles smoother than it ever did (since i've had it), and I have tons of power (except for that little point at 1500 rpm, that is).  I also put Lead Substitute in the main tank, just to let it lubricate the valve stems -- that is that the lead in gasoline was used for, right?

Anyway, I will let everyone know tomorrow night if the spring replacement does the trick.

John



From: denison
Sent: 12/4/2004 7:24 AM

I would be glad to know the AutoZone part number for those springs, mine seem to be fine, but are 32 years old.
The tetra-ethyl lead in the gasoline did have the effect of lubricating the valves, but its first purpose was to raise the effective octane; so compression ratios could be raised without causing detonation/pinging. That was in the days when high power engines might have a 7 to 1 ratio. By contrastit was 4 to 1 in a model T Ford I believe, and the high compression flathead V8 in my 28 LaSalle is 4.25 to 1. So todays gasoline is formulated a lot better, being able to run in engines at over 8 to 1 compression ratios, without the tetra-ethyl lead. I wonder if whatever replaced the tetra-ethyl lead is equally harmful to the environment?
The last time I saw leaded gas for sale was in Alpine Texas in 1993. I filled up both tanks with it, and sure enough, by the time we got to El Paso, the inside of the tail pipe was a medium gray - just like in the good old days!



From: HeavyHaulTrucker
Sent: 12/4/2004 10:30 PM

Ok, now I am getting a bit concerned.

First of all, the GM HEI distributor springs will not work in a Dodge distributor... they aren't even close.  I did verify that the springs were shot, though... in fact, it looked like one of them had been replaced at some point.  I ended up shelling out $50 for a reman distributor from O'Reily's.  I had to reset the timing by 5 degrees because of the difference between the old 'weightless" distributor and the new one -- it was that far off.

And the problem is not cured!

Granted, it is better, and the engine runs strong above 1500 rpm -- but it still detonates fuel in the carb's primary bore between 1100 and 1500 rpm with moderate throttle.  I wish I could find out what condition makes the fuel explode in the carbutetor = is it too rich or too lean?  Or is it related to intake valve timing, and my cam is shot like one guy told me?  I am getting 16" of vacuum at idle in park, 11" in drive with the brake on and when on level cruise, and vacuum bottoms out on acceleration.  Snap-back from deceleration is almost 25"

I wonder if the Edelbrock 1407 I put on could be either too much carburetor, or if the "out of the box" needle/ jet settings are too rich or lean?  It came stock with the orange (5") springs and the 1453 (.071 x .047) metering rods.  When I (belatedly) did the math to determine required carb cfm, I came out with just under 500 cfm -- maybe I have too much carb on it?

I am going to do a new timing set in the morning, from scratch -- pull #1 plug, find TDC, check & double-check.  There has got to be something I am missing here.  It seems to me that a cam wouldn't do this -- it would either run or not run, right?  Or am I wrong?

John



From: denison
Sent: 12/4/2004 11:41 PM

You are right that the cam timing being off would effect the engine operation drastically and consistently -- all of the time. So Im sure it is not that.
Having too much carburetor cfm capacity might make it run poorly at low throttle openings and low engine speeds. A 750 or 800 cfm carb should work okay, but I just don’t know the effect of a 1000 cfm carb. By poorly I mean some misfiring, but not serious. What is the cfm rating of the carb you have?
That backfiring up through the carb I associate with either running too lean, for whatever reason, or an ignition system that is not firing consistently. Do you know if you have some plugs whose gap is too small? Or a plug wire that is not fully seated onto the top of the spark plug? If it runs strong at full throttle and substantial rpm I would discount anything like sticking valves or lifters. Its really rare, but possible to have a shorting-out spark plug.
The matter of mixing air with the fuel stream is pretty important at low cruising speeds and when transitioning from idle to cruise, not important at high engine rpm. The mixing-air-in is what helps the fuel atomize as it is sucked into the venturis â€" it comes out already as spray of fuel/air mixed. At least that is how the Holleys work, and I think the Edelbrocks also.
You might want to look down into the carb primaries as you open the throttle, with the RV in neutral, and see if the fuel flow looks to be the same quantity from the left and right venturis. They should be. Might want to wear goggles while doing this too!
Your vacuum readings seems pretty good.
I guess I would be inclined to at least try a different carburetor at this point.



From: Jupp318
Sent: 12/5/2004 4:58 AM

Guys,

  I have watched this discussion for a while and thought that Dave was on the right track but now I think it's time to speak.

I would say with some confidence that the problem is a leaky inlet valve.  At low RPM the flame has time to reach the plenum under the carb causing a backfire through the carb, at higher RPM the flame doesn't have tim to travel that far and the problem goes away.  If a compression check doesn't show anything conclusive, see if you can do a leak-down check.  I realise you guys with the 440 have trouble even reaching your plugs, but it is a great way to check the cylinders. and if you do find a leaky cylinder you can listen for the escaping air in either the exhaust , the carb or the crankcase to find out if the leak is from the valves or piston rings.

I would say though that until you cure the problem carry alot of fire extinguishers!.  The very first MH I went to look at was an old Dodge Triton and when the guy took me out for a test drive we reached a hill and the engine started popping and then made a strange noise and died.  The guy then asked me to lift the doghouse whereupon flames sshot out almost hitting the ceiling.  We got the fire out but not before a lage part of the carb has melted! needless to say I didn't buy it.

Cheers Ian...



From: denison
Sent: 12/5/2004 7:51 AM

But the Triton could have been a huge bargain.........

Ian, you came up with an excellent description - a good likeliehood. Likewise a lifter that was sticking, having gotten some crud in its works, and not bleeding down. Even a small piece of hard material caught between the valve and its seat.
If this had happened to an engine that had not had any long drives for months or years, I would advise trying to drive it a couple of hundred miles and see if it freed up. If it happened to an engine that was in common use - - - thats still what I would try first, being lazy. (Its easiest)

I wish I had Ians gift for clear thought and explanations.



From: HeavyHaulTrucker
Sent: 12/5/2004 9:52 AM

denison, right now it has an Edelbrock 1407 750 cfm carb, brand new from Auto Zone.  It idles smooth when it is anywhere near warm -- no misfiring at all -- and, except for that 300 rpm range between 1100 - 1400, it runs good.  At about 3000 rpm, sometimes it will pop once or twice... but if I back off on the throttle just a hair it will stop that.

The plugs are Bosch Platinums, all gapped at .035, and the plug wires are new double-silicone wires from Auto Zone.  When installing the plug wires, I was very careful to make sure they were all seated properly.  But even with a plug wire loose, she will normally run fine -- on my trip back from Chicago, #8 boot slipped off of the plug and barely effected it.  In fact, I only noticed it when I stuck my head into the passenger side wheel well to do something else!

One thing I noticed last night after I put the distributor in... it doesn't want to go over 55-60 mph.  The engine will run up to 5000 rpm in park, but won't go above 3000 in drive.  My thinking is that maybe the dampener is off (and my timing isn't right when relying on the stock timing marks) or the carb is running lean.  Now, I wonder if the Auto Zone fuel pump I put on week before last could be too small? 

One other thing -- in the mornings it takes forever to start.  It will start once right off but quickly dies (probably from the fuel that is still in the bowl); after 15 or so cranks, it will start but misfire on all cylinders.  If I touch the throttle at all before it comes up gradually to normal idle speed, it will die right off.  Once it has come up to idle speed, then it idles & starts fine the rest of the day.  Yesterday evening, I re-connected my electic fuel pump but I haven't tried to start it this morning yet.  Now I am wondering if I have a bad fuel line that is sucking air?

This is probably a long shot, but could this be caused by a missing carb heater in the intake venturi?  There is a 1" threaded hole in the bottom of the manifold venturi, on the passenger side (I think this was for a carb heater) that is open -- it has been that way since I have owned this thing.  I first noticed it the first time I rebuilt the old TQ.  Could that, with the new carb, be causing this?  My logic (maybe questionable) is that maybe during low vacuum conditions some of the fuel is dropping into this hole causing the cylinders themself to run lean -- even though the carb is putting the correct mixture into the manifold.  Could this be a possibility?  The hole is threaded, so I could put a pipe plug into it -- but it has always been that way so I have just left it alone.

How is Edelbrock on quality?  Do you think that there is a likelihood that I got a defective carb?  It would sure be nice if the answer was that simple!

John



From: HeavyHaulTrucker
Sent: 12/5/2004 9:57 AM

Good Lord, Ian, please don't even think such a thing... you might jinx me! 

I think Denison is right on this; a bad cam or valve would evidence itself all the time.

But just in case, I do carry 2 of the 10 lb. A-B-C dry powder extinguishers, fully charged!

John



From: HeavyHaulTrucker
Sent: 12/5/2004 10:01 AM

Denison & Ian, would this happen even though the engine had been running fine for several months, and has had over 10,000 miles put on it in that time?  The oil is changed regularly, and I run 20W50 in it.

John



From: Sea Hag
Sent: 12/5/2004 10:26 AM

John , you might want to try to back up a little and check the fireing order on the plug wires at the distributor cap . I replaced mine the way they came off and thought I checked it off the numbers cast on the intake manifold a couple of times . It's hard to distingush between two of the numbers  off the manifold I think it was the 8 and 6 if I recall . I rechecked mine from the manual and found these crossed , I think they were that way ever since I got it , it still seamed to run fairly strong like that . Made a big difference once I found the problem . Just a thought . Sea Hag



From: elandan2
Sent: 12/5/2004 1:22 PM

Hi John,  Did you try changing the distributor cap and rotor.  I've run into similar situations with different engines and it has turned out to be the cap.  Whether it was carbon tracking, cracks, or a bad connection on the terminals I don't know, but it has cured the problem for me on different occasions.  Hope that helps.  Rick



From: denison
Sent: 12/5/2004 4:41 PM

John; I would agree with you that a leaky valve, for whatever reason, would be very rare occurrence if the engine had been in general motorhome use as you describe --- BUT I had an exhaust valve bend itself in the engine of my vintage airplane. A simple 4 cylinder air cooled motor, never overheated never run beyond 2800 rpm, and one exhaust valve simply began leaking a little then more, until it felt like a 3 cylinder motor when I was pulling the prop to start it. When I removed that valve, its head was just visibly no longer true with the stem! It’s the only bent valve I ever experienced that didn’t result from somebody going past the red-line on a tach.
On an old engine, a hydraulic lifter can get a piece of hardened varnish jammed in its inner bore â€" for no reason except bad luck. Its rare, but this might prevent the valve from fully closing. If its enough of a leak to cause the backfiring, I believe it would show up in a compression check.
Does the carburetor have a choke on it? Your description of the problem with starting it in the morning sounds like its either way under-choked or over-choked, or the float chamber has drained empty over night, but down into the inside of the intake manifold: hence the easy initial fire-up. Anyway, if it has a choke, it should start up and run at a fast idle on all cylinders â€" after the first 1 or 2 seconds. If it dies when you put the cold engine in gear, again that sounds like it needs more choke.
A bad fuel line sucking air is fairly common â€" if the rubber hoses from your tanks are original.
Edelbrocks have a good reputation, though no manufacturer is infallible.
I cant picture the hole you talk about in the intake manifold. Is that a passage between the two plenums in the intake manifold; the one for the right hand throats and the one for the left hand throats? And was this any different when it was formerly running well enough? You might try putting a p.t. plug in the hole to see what happens, just make sure the plug cant get loose and get sucked away to an intake port. Maybe the edelbrock is more sensitive to the air flow below the throttles than the earlier carb?
I think the Holley on my 413 is a 750 cfm. It runs just fine.
I would recheck those ignition wires and dist. cap like Sea Hag and elandan2 recommend â€" I had a Lancia V6 with two wires crossed; didn’t realize it till I found it wouldn’t rev like it used to. And look for moisture inside the distributor cap, on the rotor.



From: HeavyHaulTrucker
Sent: 12/5/2004 9:31 PM

OK, I am going to combine 3 replies into one post:

Sea Hag --  No, the plug wires are all where they should be.  When I replaced the distributor cap (remember Knoxville, TN?) I physically traced all of the wires out by feel; when I replaced the wires last week, I replaced them one at a time.  My firing order reference is taken from a printed manual -- I have misread numbers on castings before, so I don't rely on the castings unless I have no other reference.

elandan2 -- No, the cap & rotor are new.  And since the new distributor came with a new pickup coil, so is it.

denison -- Compression is good on all cylinders; in fact, when I compare my readings with how clean the inside of the engine was yesterday when I replaced the distributor -- I don't think that this is the original engine.  If so, then it has had to have had a complete rebuild sometime in the last 5 years.  There is NO varnish buildup anywhere in the engine that would normally be expected in a 27 year old engine -- the valve train is clean as a whistle, even down in the bottom where the oil drains back to the crankcase.  As for the hard starting, I think I have traced that to a combination of a partially restricted (faulty) fuel filter and under-choking.  You were right on about it dying when I try to start out with it cold!  And you are right, no manufacturer is infallible -- as my comments below will prove.  The hole in the manifold I mentioned is in the bottom of the passenger side plenum, and leads into another chamber; I have no idea where it leads, because all of the cylinders are fed from the top passages.  I seem to remember that Brenda's motor had a carb heater of some sort under the carb, but I don't remember exactly how it worked or where it brought heat from.  I don't know what the underside of the manifold looks like, so I don't know if there are any other passages on the bottom side that this hole may lead into.  I first noticed it when i rebuilt the old TQ the first time, and I just left it alone -- the engine has always ran well with it there, so I figured that it was supposed to be like that.

General Reply:
Now, with all that said, I think I have found the culprit... the transmission kickdown linkage!  You see, when I installed the new carb, no one had the transmission kickdown linkage adapter; it was not mentioned in the installation instructions, only a throttle adapter.  So I "modified" the existing kickdown linkage to work on the new carb by bending the slotted bracket that connects the throttle lever on the carb to the kickdown linkage's U-pivot mounted on the manifold.  Well, when I exchanged the original Edelbrock at Auto Zone today (Edelbrock agreed that it was defective because it had an internal fuel leak; the leak was not apparent when running, but it allowed fuel to seep into the manifold emptying the fuel bowl when the engine was not running.  Ergo, the cause of my hard starting problem), I got to talking with one of the parts people who had a lot of experience with the Edelbrocks.  I learned that Edelbrock makes an adapter for the Chrysler kickdown linkage that is required on our old Winnies.  They didn't have one (no one in town did), but they were able to get me a picture of it that was good enough to judge size scale from -- so I made one out of some flat 3/16" aluminum stock I had laying around.  It goes onto the top of the U-pivot (where the bracket normally goes) and extends forward -- the bracket then bolts to one of the holes to make it the proper length to make the U-pivot stand straight up like it does on the TQ installation.

After installing the bracket and re-adjusting the linkage, I was amazed at the difference!  I still have to fine tune the adjustment, but the popping is almost completely gone.  Now, I have to find out why I don't have any real top speed in 3rd gear -- it won't go over 50 mph.  I hope that the "fine tuning" will cure that.  We will see what tomorrow brings, I guess.  The other possibility is that the tranny needs to be rebuilt -- no big deal.  JC Whitney sells a 727 rebuild kit for $59.99 (http://www.jcwhitney.com/autoparts/ProductDisplay/c-10101/s-10101/p-229695/mediaCode-ZX/appId-469775), and from what I have read, it doesn't seem to be particulary difficult to do.  I can rent a tranny jack at United Rentals.  That sure is cheaper than buying a rebuilt one!

Thanks for all the good information, everybody!  Who would have thought that such a little bracket could cause so much trouble??

John



From: elandan2
Sent: 12/6/2004 12:15 PM

Glad to see you fixed the problem John.  You are right there, who would have thought!  Rick



From: denison
Sent: 12/6/2004 1:34 PM

Glad to hear of the improvement. I dont picture the kickdown linkage, but no matter.
About the tranny needing rebuilt: I have no basis for thinking that a transmission not being okay would limit your top speed in 3rd gear. It may be true, I just dont know. It would have to be something like an overrunning clutch that was slipping, and allowing higher engine rpm without transmitting the torque to the transmissions gearsets.
I can believe it coould be fuel starvation. You could temporarily put a fuel pressure gauge in the line going to the carb, after any and all fuel filters. All you would need is a fuel press. gauge, some hose, and a T fitting. It should read above 5 or 6 psi, regardless of speed.



From: Jupp318
Sent: 12/6/2004 2:13 PM

Guys,

Glad to hear that all is OK again.  Can I ask a big favour, can you all post the part numbers for these linkage conversions that you have USED.  I stress used as being in the UK I want to be sure that I order the correct linkage for my Edelbrock.

When I service the transmission I want to have the correct linkage in place such that I can then do all the proper adjustments as per the book.  Seeing as there is a "throttle" linkage to the tranny I guess if this is incorrectly adjusted then shifts may be in the wrong place which may in turn hurt economy and cause the tranny to overheat.

Thanks in advance
Ian...



From: denison
Sent: 12/6/2004 6:06 PM

The next time I use the Winny I think I will disconnect the transmission linkage and lay it to one side -- just to see if that has any effect on the upshift points.
Mine has never downshifted from me putting the pedal all the way down - at any speed. I have pulled it into 2nd when I wanted to accelerate from 15 or 20 mph. On an upgrade I pull the lever into 2nd if I feel the need, which is usually on side roads in the hills of the eastern states. I seldom get opportunities to drive in the mountains of the western states, but the same would apply: Including going down the longer/steeper hills in 2nd.
I am currently happy with the upshift points too. I would say it goes from 1st to 2nd about 12 mph, and from 2nd into 3rd about 25 mph. I am seldom in a hurry when I start out with the Winny.



From: Jupp318
Sent: 12/6/2004 6:56 PM

Dave,

When I fitted my Edelbrock back in the spring I didn't see what I was doing wrong with the linkage as it all just seemed to fit, but the "throttle" linkage to the tranny was just running in the slot and didn't move.  The upshot was that the tranny shifted to 3rd straight away and bogged the engine.  The linkage setup I have at the moment is just a bodge to get things working which is why I'm still keen to get the proper parts.

I reckon one part is EDL 1481 (Summit) but a kickdown part was talked about and I cant find a number for that.

Cheers Ian...



From: HeavyHaulTrucker
Sent: 12/6/2004 10:47 PM

Here I go with the combined replies again...

Denison -- Third gear is shot.  It is slipping so badly, all I can get out of the old girl is 55 mph ar 3500 rpm; if I have a downhill, I can get her up to 65 or 70, but she will slow down again on level ground.  On even a mild rise (such as a freeway overpass), she loses 5 mph or more.  I think I will be ordering that JC Whitney rebuild kit soon -- but before I do, I think that I will check fuel pressure as you suggested.  BTW -- don't just lay the kickdown lever aside.  If you are going to disconnect the linkage, wire it back about 3/4 of the way; I have read many articles that have said that running with the linkage either disconnected or tied forward can damage the tranny.

Ian -- The kickdown adapter you need is Edelbrock part number 8022 along with the throttle adapter you already mentioned.  The adapter goes upright; one end replaces the slotted bracket on the U-pivot, and the slotted bracket bolts onto it in the hole that works best for your manifold height (the adapter is designed to be used with any height manifold/ carb setup).  You can adjust the angle between the two parts to give you the proper kickdown adjustment while raising the linkage to acommodate the higher carb linkage on the Edelbrock.  BTW -- I did not actually use theirs; I fabricated my own based on their pictures -- same thing, same results.

General Reply:

One thing that no one has mentioned is the adjustment for the kickdown band and the low/ reverse band.  I will relate these below.  The kickdown band adjustment is on the side of the tranny, just above the shift and kickdown levers.  The low reverse band adjustment is inside the pan, on the drivers side of the valve body, near the rear.  It looks like a piston with a rocker on it.  According to the Chrysler Service Manual, both of these adjustments are supposed to be done every 30,000 miles or 6 months.

Kickdown Band Adjustment:  Locate the kickdown adjuster on the drivers side of the transmission, just above the kickdown lever.  Clean around it well, so that the locknut will spin freely when loosened.  Loosen the locknut about 5 turns so that it does not bind the adjuster.  Turn the adjuster in by hand and tighten it to 72 inch/ pounds, then back it out 2 1/4 turns.  Hold the adjuster while tightening the locknut.  Done.

Low/ Reverse Band Adjustment:  (This is best done at time of fluid change) Drop the tranny pan.  Loosen the locknut about 5 turns so that it does not bind the adjuster.  Turn the adjuster in by hand and tighten it to 72 inch/ pounds, then back it out 2 1/4 turns.  Hold the adjuster while tightening the locknut.  Install new gasket on tranny pan & bolt it up.  Refill tranny with fluid.  Done.

John



From: <NOBR>restoholic</NOBR>
Sent: 12/7/2004 7:09 AM

Go to summit racing and purchase a "Lokar" kickdown cable and bracket. It works great!!

Bill



From: Liv42dayOK
Sent: 12/7/2004 7:21 AM

I thought the direction that this Discussion has taken was so valuable, I started 2 new Discussions separately on them so they could be easily found with the Message Search in the future.  One for the linkages and one for the band adjustment.  Thanks, John! - Sob



From: denison
Sent: 12/7/2004 7:28 AM

Besides helpful and knowledgeable members, we have an excellent site manager.  Thanks Sob!



From: Liv42dayOK
Sent: 12/7/2004 7:31 AM

Ok, make it 3 Discussions... "727 Transmission Rebuild Kit".

- Sob



From: restoholic
Sent: 12/7/2004 7:34 AM

My apologies!



From: HeavyHaulTrucker
Sent: 12/7/2004 9:34 AM

restaholic said,
"...purchase a "Lokar" kickdown cable and bracket. It works great!!"

Oh my God, now this group has ESP!    I was just thinking about asking if anyone had any experience with these kickdown lever replacements!

John



From: HeavyHaulTrucker
Sent: 12/8/2004 8:47 PM

Well guys, I have the problem just about solved, I think.

I have been tinkering with the kickdown linkage, which has worked wonders.  But it was still popping a bit, even when I have it to the point where I can get good acceleration and speed out of her -- she will get up to 65 now.  I still think it is time for a rebuild on the tranny.

I ordered the Edelbrock #1464 Spring Assortment, which allows me to change the springs in the step-up pistons based on vacuun readings.  I changed the stock orange spring (by experimentation) finally to the lowest one (blue) and the popping is all but gone now.  If I really get on it, it will pop a few times until I get to about half throttle but when secondaries kick in that stops.  I think I should have ordered the #1480 Tuning Kit (which contains both the spring assortment and all of the metering rods) because I think that I should go to a leaner or richer rod on the Power stage.  I might order it yet... I haven't decided.  My fuel mileage has definitely gone up, though.  Exactly how much, I don't know yet.

I want to check into some fuel staining on the front of the fuel tank that I noticed late this afternoon; I may have a small leak in the pickup tube where it comes out of the tank.  If so, that would probably explain the popping (and you would have been right about fuel starvation, denison).  But that is a task for tomorrow.

John



From: HeavyHaulTrucker
Sent: 12/12/2004 1:52 AM

Well, back to the drawing board, I guess.

I pulled the intake manifold yesterday.  There was a 3/4" threaded hole in the bottom of the passenger side plenum -- right under the primary throttle plate -- that was open to the heat riser passage.  My theory was that possibly fuel was dropping into this h