No Fuel to Carb at OP temp

Cooneytoones · November 16, 2008, 11:07 PM

Sent: 7/9/2006 1:20 PM

440-3 new rebuilt TQ....timing is good, new cap, coil, rotor, wires and plugs.....First thing you think of is vapor lock......................not it

Installed an new mechanical fuel pump, all new 5/16 lines from tanks to selector valve( also new) to carb and new fuel filter....gas is clean, filter is clean...vacuum is at 15 to 16 inches at idle and drops to 14 at 600 RPM in drive... has a back lash at idle to 28 inches......will run at idle and high speed perfect, until it comes to operation temperature then it starves for fuel.......it will start right back up but vacuum is a little lower....it will idle but as soon as you move the rpm up it starves for fuel......

Could the new fuel pump be a lemon? The cause of this perplexing affair.....
It's the only thing I can think of...if the crimp on the fuel pump (on the suction side) was bad...when it gets hot and expands a little....it would suck air, and you would never see a leak......as soon as it cools down it works just fine again, until it gets to 180 degrees, than very little fuel getting to carb...Have not done a pressure test on the fuel line yet..any other ideas?

PISSEDOFFPERPLEXEDTIMMY

From: Cooneytoones Sent: 7/9/2006 6:36 PM
Started and ran perfect a little while ago, but as soon as it was up to just about 180....not enough fuel.

Timmy

From: denisondc
Sent: 7/9/2006 7:09 PM

I haven't played with any ThermoQuads enough to know, but those symptoms on other carbs would make me think the idle circuit in the carb is okay, but the cruise circuit might have a blockage or other problem. I have experienced this with a main jet that was partly clogged, and with a clog in the percolation tubing, that mixes air with the fuel stream before it flows into the venturi. Once this was because of an insect in the air bleed tube for the percolation function. Another time it was an incorrect gasket at the base of the carb. The proper gasket completed a vacuum passage, which the improper one did not. The thing is the carb would work -okay- if the choke plate wasn't open all the way. Once the choke was fully open, the cruise circuit problem could not be ignored.
If the secondary throats on the carb try to open too soon, this could also be a result. On some carbs there is a mechanical linkage that keeps the secondary butterfly closed until the primaries aren't close to wide open.
Something that changes when the engine gets warmed up is on the vehicles having a vapor canister. They have a temperature sensitive vacuum switch, part of the emissions control system. Once the engine gets close to running temperature, the port to let the engine suck in vapors from that canister is supposed to be opened. This is not supposed to happen when the engine is idling, but only when it is running at a good rpm. The tube from the canister is a fairly large one, and if it were opening too early (too close to an idle condition), could result in an air leak big enough to effectively starve the engine for fuel.
Other than these far-fetched guess, I am stumped.

From: denisondc
Sent: 7/9/2006 7:11 PM

I meant to say '......that keeps the secondary butterfly closed until the primaries ARE close to wide open''.

From: Slantsixness
Sent: 7/10/2006 6:16 AM

Timmy,
Incorrect float level Setting?
Carb not adjusted right?
Fuel peculation (Vapor Lock)

I know you said you had all new fuel line, but a loose clamp, pinched hose, rusted or pinholes in the pickup tube (in the tank) would cause fuel starvation. Clogged filter even?

If it is vapor lock, dress the fuel line away from the engine block as much as possible.

I know you're still using the dual tank selector switch... is it mechanical or electrical? the Mechanical ones can get clogged up and starve the fuel pump.... even this could cause your symptoms. (at low rpm the pump pumps less, but has a longer duty cycle. when at 2000 rpm it pumps more, but has a shorter duty cycle. If the pump is drawing air instead of fuel, or a mixture, the pump would act like you're seeing at higher RPM. Could the new pump be bad? Sure, and it might just be...

Major vacuum leak off idle? Did you try the unlit propane torch? You might just be surprised....

Are you sure it's really running out of fuel? you should see fuel spray in the primaries at 1800rpm.

lots of other ideas.... but you know how opinions are....

Tom

From: Cooneytoones
Sent: 7/10/2006 6:38 PM

Hmm 2 Denison you may have hit on something that I was thinking about...but so much of the canister system is MIA I have to get a good schematic of how it is supposed to be.
Both carbs create the same problem and I adjusted the floats three times in the one I rebuilt. The are brass floats. with both carbs doing the same thing I can rule out the floats I think. the TQ in my '76 service manual is different to some extent even fro\m the one that came on it, (must have been a rebuilt before I got it. I don't think it is the original, there is no tag...
The one that Wayne got me is even different yet .... Besides the tree being set way too high, It has a bowl dump valve, which I believe Carter did away with in 1973 or '74. The problem with the '76 is it right in between the non-smoger and the smogger carbs which we're changed right around then...a friend of mine says I can fix it in one word, Endlebrock ................. but that means the Doghouse will not be on the road for a least a year. because by the time you get done with the carb, adapter kit, and linkage kit it's near 400 bucks..
So I may try going to back to a good electric fuel pump one rated for 7 to 9 psi this way I can keep the fuel lines away from the exhaust manifold...the electric pump that was on there before was only rated for 3.5 to 4 psi, that was the other reason PO had have the carb closed off besides having a leak inside the carb....and it ran just fine lacked a little power, but not bad....
....all the fuel lines are as far from heat as possible...no blockages as far as I can tell.....

all the linkage which is manual on the TQ seems to be working correctly....It runs great when it comes off of high idle and the idle linkage cam lets the secondaries open, they open fine and work great ...rig has good power under load.....for about 2 to 5 minutes, maybe even 7 minutes, enough time to make it three miles at about 35 to 40 mph on a country road with some big hills....then it will start to run rough vacuum starts to go wild, then no fuel getting to carb... it looked like to me there was air in the fuel filter which is also clean as a whistle.....it will stall and I can restart right away, but will not get enough fuel to do anything more than idle rough.

I am also going to do a pressure test to see if it is loosing pressure in the fuel lines.......I still think it may be the $20 Autozone fuel pump....sucking some air on the suction side of the pump...didn't have time today but I'm going to pull that pump off after I do a vacuum pressure test on it

I rechecked all fuel line connections, they are tight....
I have a electric selector valve which is new.....took it out, it is clean and not blocked.....
now I could have a pin hole in the pick-up tube or the sock could be clogged....but without getting inside the tank that would be a guess.....
and Denison may have hit on it......either it is in the damn emission part as Denison stated... both carbs do not fit the emissions my service manual shows...not the same ports on either of them ...close but not...

I was wondering if I put that old electric back, put it inline with the mechanical (tee in in front of the selector valve as a booster), since it is only rated at 3.5 to 4 psi,
if it might help...Just a thought. Any other thoughts are very Welcomed...and much appreciated....MY wife's is "SELL IT"..... Hmm

Timmy
Thinking

From: MSN Nicknametatkin
Sent: 7/10/2006 7:16 PM

Do you have headers ?

Reply

Recommend (1 recommendation so far) Delete Message 8 of 52 in Discussion
From: denisondc Sent: 7/11/2006 10:56 AM
Have you tried some air pressure back into the fuel line - to help clear any clogging of the fuel pickup 'sock' that is at the end of the pickup tube. I had to drop one of my tanks, and found that sock was not only clogged, but had split open from my attempts to blow air back in. I didnt replace it, and it has worked fine since.

From: Cooneytoones
Sent: 7/11/2006 5:53 PM

One quick test I am going to try today to see if I can eliminate the pick-up tube or sock being collapsed or clogged, is to remove the line from the tank (actually from the selector valve) and run the line from a remote fuel tank (5 gallon can of fuel)....this should tell me if problem is the pick-up..if the symptoms clear up..then we have found the culprit....if not...next step will be to do a vacuum test on the fuel pump to see if it is holding pressure....after that......

?? Fuel pump flow test was good... it is delivering more gas than the book says it needs to, ....At idle, in 30 seconds pump delivers 24 ounces of fuel.....book says minimum required for the TQ is, 16 ounces in a minute of less.

So I'll start with the simple and go from there....any other suggestions ...I'm all ears....... Ear Ear Ear Ear Ear Ear Ear Ear Ear Ear Gossip

On a footnote:
I'd like to drive the thing instead of working on it..but I guess you (or at least I) can't do one without the other....my wife says she'd like to go more than three miles down the road.....seems that on all our trips, that's as far as we can make it before a breakdown. This is the 4th time it's happened. Maybe I'll be lucky with number 5.

alwaysworkin'onthedoghousetimmyHammering Sawing

From: Cooneytoones
Sent: 7/11/2006 5:56 PM

talkin' ..No headers.....

Timmy

From: jbmhotmail
Sent: 7/12/2006 11:17 PM

In message 1 you said: "... has a back lash at idle to 28 inches....." would you explain.

From: Slantsixness
Sent: 7/13/2006 5:18 AM

Tim meant
"28 inches of vacuum when you rev the engine and let off the accelerator ("backlash")." or "decelerating to idle".

I'm fairly certain he didn't mean his valves has 28" of backlash! (now THAT would be a problem, eh?)

Tom

From: Cooneytoones
Sent: 7/13/2006 7:11 PM

Yes IBMHM, as Tom said, at Idle, I am showing 15 to 16 inches of vacuum....when you put the throttle to the floor quickly then let off the throttle, (going vrooom vrroooom vrrrrroooommm....it doesn't quite sound like the 440 in print) the vacuum will go down a little as your throttle and rpm go up, then jumps to 28 to 30 inches upon the engine rpm and throttle coming down... I do believe this is a good sign of stuff working correctly.
Truck

Yes 28" of backlash on the valves may be a major problem.....and would more than likely cause several gaping holes in the engine....or at least some parts rattling around loose inside....LOL

INEED50BACKLASHESTimmy

From: Cooneytoones
Sent: 7/18/2006 9:06 PM

Finally found the problem with the fuel delivery to the TQ...after all that was done it was a pretty simple solution, and I have to thank and credit Tom (slantsixness) with the answer to the problem...Well to start I tried to run a new steel line from the mechanical pump to the carb, well I don't have stock in steel and fially gave up. Since the original line was MIA, and I have never seen or can't remember ever seeing what the original looks like, but to try and bend a steel line to go from the pump to the carb involves several bends..up the engine, missing the fan, coil, distributor, wires and the alternator not to mention the lower radiator hose is also in the way...It was like trying to thread a needle with chop sticks...and this boy could not get it right, I don't give up on many things.....I ruined several pieces of steel line trying. I finally said, more like screamed, "UNCLE!"
So, I did the next best thing, re-route it. Now as all of you with the 440 know...there is a lot of heat in and around that engine, (and Dodge's placement of the mechanical pump is an engineering feat in itself...... so I took the line up the radiator support, and along the oil fill tube......

This is where the problem happened...
The oil filler tube is approx. 1 1/2 to 2 inches higher than the carb inlet.....so when the gas startes to flow from the pump, a little air bubble forms in the highest part of the fuel line stop the gas for a mere second, and then cause a siphon which then caused the floats to close when the carb was calling for more fuel, the floats were closed....the bowl would go empty, and by the time the floats would open, fuel in the line was vapor and air........and no fuel (or a very small amount) would get to the carb once Operating temperature was reached.

Again Thank you Tom for your help in figuring out this.....You not only hit the nail on the head.....You drove it home....And Denison thank you too, You made me look and figure out a few more thing to check, which needed to be done....

My solution to solve this problem, and it is running as good as it was the day it came out of the Showroom. I put on a new electric pump. (5 to 9 psi) I know that some of you are against this...fuel lines stay away from the big sources of heat and IT WORKS ...... it works....and like an old parts guy I used to know always said, " If it fits & works, It goes."

I may try again (someday) to go back to the mechanical pump, but not until I can find an original fuel line, or a tube bendin' buddy, cause I surely can't get it myself. I only get me, bent out of shape...

So I close this saga of the Doghouse, with many lessons learned....and hope now, that I can drive the damn thing for the rest of the summer without having to work on it....I want to reserve that for the winter when I don't want to drive....

Timmy My Fingers Are Crossed

From: Slantsixness
Sent: 7/19/2006 5:10 AM

I'd say Go for it! (With Debbie's approval....)

Wish I could go. Joey can't travel, lost a bunch of leave time due to the flooding, and lost a weeks worth of preparatory work on Smurfy (like the generator repairs, for one thing...)

Good Luck!

Tom

From: DampDude007
Sent: 7/20/2006 10:42 AM

Sweet fix !!

From: Cooneytoones
Sent: 7/20/2006 5:21 PM

Thanks....so ended that saga, on to another....Blew a high pressure Power Steering hose today on the test run...
But that is for another post....Damn......I just might put a block foundation under the Doghouse...

Timmy

From: ClydesdaleKevin
Sent: 7/21/2006 9:29 PM

LMAO Tim!!! I have come to the conclusion that until we replace EVERYTHING on our rigs, something is gonna break! Been there done that! I keep chuckling when I read the posts here about "one thing after another" cuz I keep replacing one thing after another! Tell the wife it will be OK...it will eventually taper off to where its only routine maintenance...I THINK I'm almost there...lol. Ask Tom about almost losing an eye when MY high pressure power steering line went at last year's jam!...lmfao!!!

Kev

From: Slantsixness
Sent: 7/21/2006 10:29 PM

You laugh now....!
But back then......
you soiled your pants!

[Food Fight]

From: Cooneytoones
Sent: 8/3/2006 10:56 AM

On the way to Indianapolis today and not going to make it......Well it's got me stumped......It run like factory new for about 30 miles and then starts starving for fuel.....vapor locking.....if I move the line any further away from heat sources, other drivers would be able to syphon fuel while going down the road....it would be on the outside of the rig.
It comes to 185 degrees (and stays there).......outside engine temp is real hot, hotter then the internal by far......I put it back to the original way the PO had it and it ran like a charm for about 15 miles more then it stars to loose vacuum and will stall......no fuel to carb at all.....have to let it cool then it will run like hell.....for about 15 minutes smooth and 4 barrel sounds great....then boom no gas.
It's not the pick up tubes, the gas and fuel filter, gas is as clean as when it comes out of the pump. Electric fuel pump shows 8psi I have plastic strapping holding rubber gas line and the plastic is not melting and the line is not even as soft as my old line use to be when it was at top operating temp..It seems like its vapor locking in the carb itself... .....not sure what it is when going down the road and the vapor lock happens....but I'm about ready to commit Winneside.......
Any guesses...... Myself, I have come to the conclusion that the TQ is a piece of crap. I can't understand how it could run great over 3.000 miles as a three barrel with and elcetric pump that put out 2.5 to 3.5 psi.....and now its the way it's supposed to be, and won't run?

Down with the Doghouse Timmy

From: Cooneytoones
Sent: 8/3/2006 12:23 PM

Here are a few thing I found about my problem, I was wondering if anyone tried any of these, especially the T near the carb for a return line. Before I tried that.

I was going to try and take a piece of WHITE 5/8th's water hose, and put my 5/16 line inside of it....this should act as a cooling buffer between what ever is heating the lines and the fuel since white is heat reflective...
and below are some other fixes...

What can be done to avoid vapor lock ?
In most modern vehicles, the fuel pump is submerged in the fuel tank and pumping (pushing) fresh, cool fuel all the time towards the engine, with a return line allowing excess fuel (and possible vapor) to return to the tank. No long suction line here. So, the next best thing is to install an electric fuel pump as close as possible to the fuel tank and to make a provision for a return fuel line with a slight restriction (in the return line) at the T-junction you make near the carb, thus allowing for enough pressure to fill the carb bowl. In this manner, your fuel line will be pressurized for most of its length and the short suction section should stay cool enough to make vapor lock a thing of the past, even in your vehicle.
Vapor lock is a problem that mostly affects petrol-fueled internal combustion engines. It occurs when the liquid fuel changes state from liquid to vapor while still in the fuel delivery system. This disrupts the operation of the fuel pump, causing loss of feed pressure to the carburetor or fuel injection system, resulting in transient loss of power or complete stalling. Restarting the engine from this state may be difficult. The fuel can vaporise due to being heated by the engine, by the local climate or due to a lower boiling point at high altitude. In regions where higher volatility fuels are used during the winter to improve the starting of the engine, the use of "winter" fuels during the summer can cause vapor lock to occur more readily.
Causes and Incidence
Vapor lock was far more common in older petrol fuel systems incorporating a low-pressure mechanical fuel pump driven by the engine, located in the engine compartment and feeding a carburetor. Such pumps were typically located higher than the fuel tank, were directly heated by the engine and fed fuel directly to the float tank inside the carburetor. Fuel was drawn under negative pressure from the feed line, increasing the risk of a vapour lock developing between the tank and pump. A vapor lock being drawn into the fuel pump could disrupt the fuel pressure long enough for the float chamber in the carburetor to partially or completely drain, causing fuel starvation in the engine. Even temporary disruption of fuel supply into the float chamber is not ideal; most carburetors are designed to run at a fixed level of petrol in the float chamber and reducing the level will reduce the air:fuel mixture delivered.
Carburetor units may not effectively deal with fuel vapor being delivered to the float chamber. Most designs incorporate a pressure balance duct linking the top of the float chamber with either the intake to the carburetor or the outside air. Even if the pump can handle vapor locks effectively, fuel vapor entering the float chamber has to be vented. If this is done via the intake system, the mixture is, in-effect, enriched, creating a mixture control and pollution issue. If it is done by venting to the outside, the result is direct hydrocarbon pollution and an effective loss of fuel efficiency and possibly a petrol odor problem. For this reason, some fuel delivery systems allow fuel vapor to be returned to the fuel tank to be condensed back to the liquid phase. This is usually implemented by removing fuel vapor from the fuel line near the engine rather than from the float chamber. Such a system may also divert excess fuel pressure from the pump back to the tank.
Most modern engines are equipped with fuel injection, and have a high pressure electric fuel pump in the fuel tank. Moving the fuel pump to the interior of the tank helps prevent vapor lock, since the entire fuel delivery system is under high pressure and the fuel pump runs cooler than if it is located in the engine compartment. This is the primary reason that vapor lock is rare in modern fuel systems. For the same reason, some carbureted engines are retrofitted with an electric fuel pump near the fuel tank.
Other solutions to vapor lock are rerouting of the fuel lines away from heat generating components, installation of a fuel cooler or cool can, shielding of heat generating components near fuel lines, and insulation of fuel lines.
A vapor lock is more likely to develop when the vehicle is in traffic because the under-bonnet temperature tends to rise. A vapor lock can also develop when the engine is stopped while hot and the vehicle is parked for a short period. The fuel in the line near the engine does not move and can thus heat up sufficiently to form a vapor lock. The problem is more likely in hot weather or high altitude in either case.
Incidence with other fuels
The higher the volatility of the fuel, the more likely it is that vapor lock will occur. Historically, gasoline (petrol) was a more volatile distillate than today and was more prone to vapor lock. Conversely, derv, employed in diesel engines, is far less volatile than petrol and thus these engines hardly ever suffer from vapor lock. However, diesel engine fuel systems are far more susceptible to air locks in their fuel lines as standard diesel fuel injection pumps rely on the fuel being non-compressible. Air locks are caused by air leaking into the fuel delivery line or from the tank rather than the fuel evaporating in them. Eliminating such air locks requires an extended period of turning over the engine using the starter motor or manually bleeding the system.
Timmy

From: Cooneytoones
Sent: 8/3/2006 12:28 PM

Oh, by the way, the mechanical fuel pump is not hooked up.....I am only using the electric pump at this time.

Timmy

From: DaveVa78Chieftain
Sent: 8/3/2006 1:41 PM

My understanding of the fuel return line on later engines is that the injectors require the fuel to be under a constant high pressure. The fuel regulator maintains that pressure and dumps excess fuel back to the tank. To do that, the fuel pump has to put out a lot higher pressure than the regulator setting. Carbs with floats did not require that constant high pressure. A TQ requires only 6-7.5lbs of pressure.
The idea behind the plastic bowl is to prevent vapor lock (cooler operation)
Vapor from the carb is returned via the charcoal canister.

Questions:
1. Is your mechanical pump still in the fuel path? The output from the electric pump should be directly feeding the TQ. Flow rate maybe reduced if routed through the mechanical pump.
2. Do you by chance have one of those clear in-line fuel filters mounted up at the carb input? They sure make it easy to see if fuel is reaching the carb. They are cheap and the element can be cleaned. This is one of the first things I would do. Being able to see the fuel status at the carb input points you in the right direction (fuel delivery or carb).
3. Are you using plastic or brass floats? If plastic, they may have out lived their usefulness.
4. Is the float height set correctly?
5. When the problem occurs, are the primary metering rods being raised when you depress the throttle? The piston that operates the metering rod hanger may be binding due to heat expansion. There is also a cam under the piston that forces the piston to rise however, normally the piston is vacuum operated. The piston performs the same basic operation that a power valve on a holley does. Enriches the mixture when intake vacuum drops under about 6.5lbs. The spring under the piston could be weak. Weak spring results in lean run condition (rods pulled into jets) There is an adjustment for setting the metering rod height however it is not supposed to be touched (factory adjustment). It's that little screw in the center of the metering rod hanger (top the piston). You can adjust the mixture with it though. Clockwise to richen (raise the metering rods), counterclockwise to lean (lower the rods).
6. You say no fuel to carb. Do you say that because when you depress the throttle there is no gas squirted from the accelerator pump? Or did you remove the TQ top and see no gas in the bowls? Might be just the accelerator pump circuit. There is a very small plastic tube in the accelerator pump circuit that could be collapsing with heat. Also the ball valve under the pump could be binding up (heat expansion or incorrect ball size) not allowing gas to refill the chamber.
7. Have you really taken a close look at the plastic bowl? Seems possible it has a crack that leaks when heated allowing gas to leak out of it into the intake. There are 2 o-rings in there that can age letting the gas leak into the intake overnight. Possible they do that when heated up. Engine floods then stops. I would think you would see/smell fuel with an electric pump though. Was just a thought.

I asked a lot of this based on your initial comment of '440-3 new rebuilt TQ'.
Rebuilt means some probs could have been introduced.

Dave

From: denisondc
Sent: 8/3/2006 3:19 PM

I admit to being stumped. I think I would put a fuel pressure gauge in the feed line close to the carburetor. If it showed a steady reading of anything over 4 psi, then I dont think its vapor lock.
I don't imagine your motor home experienced a serious vapor lock problem when it was new, so either something isn't right - maybe the carb, maybe a lack of air flow over the engine due to a weak fan clutch, a stuck heat riser valve, ...., OR, something is different from when it was new. Where is the electric fuel pump located? Where is your fuel filter located?
Changing to a different carb would hopefully highlight shortcomings of the carburetor. I don't think of any carburetor as being a bad design, if it only began giving problems when it was over 25 years old - but a new one, or at least a different one, might be worth the effort.
My 413 uses the original mechanical pump, original fuel line routing, and hasnt shown any sign of vapor lock since I heat-shielded the fuel lines and aux. tank in 93. We have driven it in temperatures of 100f many times since: Though 100f was the temperature in the shade, whereas we were buzzing along on black macadam highways, or idling in heavy traffic.
Of course the weather has been unusually hot, perhaps it will be much better when its only 85 or 90 outside?

I have tried putting clear fuel filters in a location close to the carburetor. I couldn't tell much of anything about the fuel flow. There seemed to be visible fuel flow when it was cold, but when it got hot the filter seemed empty. The engine kept running just fine, even on hills. I admit I only tried this in cool weather. I dont care to drive in hot weather with the engine cover off.

If the engine is not getting any fuel when things are fully warm, it would still start up with a squirt of starting fluid down the carburetor.
Does your engine have an exhaust crossover through the intake manifold? Could you possibly close that off? It would interfere with the operation of the EGR, but it wouldnt hurt anything else. If there is exhaust gas crossover and the valve is stuck in the -cold engine- position, it will make the base of the carburetor way too hot.

From: The_Handier_Man
Sent: 8/3/2006 8:48 PM

Well here goes my input on this problem. You might have tried them all but....Have you tried getting it running again when hot by pouring fuel in the carb, with air filter off? Could it be a valve train problem? Do the valves not close fully when hot so it has low compression? Have you bought stock in the local auto parts store yet? And is your wife still talking to you? Best of luck, Les

From: Cooneytoones
Sent: 8/3/2006 9:01 PM

The fuel pump is located next to the selector valve ( which is electric)... so I had to jump the line over the drive shaft...it is about maybe 10 inches long....the line coming out of the tanks are both about 12 inches long to the selector valve...this is the place I think where the heat sync is happening there are two shields because the selector valve sets right above the muffler....after the selector valve like I said, it goes above the drive shaft and hooks into the E fuel pump then follows the left frame rail for a short length, goes up where the doghouse opening starts over the rear of the transmission (it is about a foot or more away from the tranny right along the bottom rear of the opening to the doghouse and then to the carb....the filter is right behind the transmission dipstick in the corner of the opening
It is vapor lock....you can see the vapor in the carb when it shuts itself down....Loads of vapor just steams right up out of the primaries.

I still think ...You may be on to something as you said, it might be in that egr and the hot run valve not opening or stuck in the cold positions....Because it seems to happen like someone threw a switch.......from running great to boom nothing usually upon deceleration or it will start loosing power while cruising along and the vacuum will drop off and it feels likes it running out of gas.....I climbed a hill today with took it at the top fully loaded 55 mph from about 3 mph at the bottom, there is a 90 degree turn....my Chevy Blazer has trouble getting to 50 mph on this same hill starting out at 20 mph and that has a 4.3....the hill is one mile long and temperature never moved from 185 so the fan clutch is good it will blow a troupe off someone sitting in the drivers seat with the doghouse open....
I ran it hard today trying to test it out..then the vapor lock.......started right up an ran great about one and a half hours later.....
I'm going to add some more heat shielding and cover the fuel lines with some type of shielding...then I will see if it is that or what you may be on to with the EGR......................but for now,
I'm, for a short time, going to take a break from working on it.... because it's got me to a breaking point right now.....and I don't want to accidentally drop a lit cigarette while working on a gas line.

Timmy Matches Flamethrower

From: DanD2soon
Sent: 8/3/2006 10:55 PM

Timmy,

I know it's off-the-wall, but...

* Have you tried it with your unvented gas caps removed?
* And, have you tried switching tanks under load when it begins to stall?

We had similar issues several years ago that I was convinced were engine temp related and were not. A combination of coincidences (un-vented caps & clogged tank pick-ups) were causing a vacuum to be created that the fuel pumps could not overcome. (Ours had an electric fuel pump between each tank and the manual fuel selector valve) The time it took for that vacuum to build to Problem proportions was about the same time it took to get to really good operating temp. Switching tanks would relieve the problem for a while and switching back and forth got us where we were going with only a few forced "last ditch" side-of-the-road stops to let the "engine cool." (actually to let the vacuum bleed off both tanks) Our engine would also Start & Rev-up, no load, but would not Pull - Put it in gear and give it gas and it would die!

I know (from last weeks' "Vented/Un-vented Cap" thread) that you have and are supposed to have un-vented caps, but as Dave suggested, there may be a contributing canister system problem...

Good luck,
DanD

From: denisondc
Sent: 8/4/2006 5:46 AM

If you have an EGR valve, then you DO have exhaust gases coming into the intrake manifold, if only to feed the EGR valve. That is normal and would be expected. But the EGR valve only lets in a small amount of recycled exhaust gases. A heat riser valve that is stuck in the closed position will keep directing exhaust gases in large volume, up and across the bottom of the intake manifold. If you do have an heat rister valve, it will show up as a metal rod sticking out of one of the exhaust manifolds, probably close to the middle between the forward and aft ends. It would have had a bimetallic spring to operate it, but I dont know if that would have been external, or internal to the manifold.

My 413 doesnt have an EGR valve, not a hear riser - and instead of exhaust gases to heat a cold intake manifold, it uses coolant coming from the engine heads.

From: Cooneytoones
Sent: 8/4/2006 6:20 AM

I'm not sure either, but on mine...it has a dual hose connector on the front of the engine next to temp sending unit by the thermostat housing a little dual connecting boot, two hoses (very small hoses about 1/4" comming of of it, one hose goes to a little dash pot looking valve on the left side of the carb, there is a plate under it, is it possible EGR it is internal...The other hose coming off of this was never hooked up, even before when running good as a three barrel. I believe it used to go to a vacuum booster (which is mia) and has something to do with what is called the CCEGR valve. But the service manual and the carb I'm using don't even show the same vacuum ports, so the carb that is on there (that the rig came with) I'm sure is not the original....and was a replacement rebuilt.....and the new rebuilt that I got from Wayne (which is still in the box) the air horn is a little different. It has a bowl dump valve and less vacuum ports, and a fuel bowl vent which goes into the air cleaner. I'll take some photos and post them on this thread when I get a chance. Thanks Dave....

Timmy

From: Cooneytoones
Sent: 8/4/2006 7:05 AM

to answer all your questions....on the carb...metering jets are set correctly and carb currently on there was rebuilt by me and taken apart twice to see if anything was not correct...springs are good , tube is hooked, everything is as it should be according to the kit instructions and the Carter manual...
the metering rods look good, the other carb (factory rebuild) metering rods are set too high (for a car or light application)...the old carb (that is on there now has brass floats...The new factory rebuild has ? (probably plastic) I adjusted the floats to what the rebuild kit said, then re adjusted to allow for brass being a little more buoyant..then put them back to factory specks. Problem occurs with both carb.....factory rebuild it just happens faster. Problem occurs on both fuel tanks....

..I've had the caps off so it is not locking pressure in the tank...I have a clear filter on it....fuel is clean....and as Denison said, at first you can see the fuel running through the carb well, but after running near hot and the fuel fills the filter it is hard to see.....
fuel is definitely vaporizing......either in the lines or right in carb itself due to the heat from exhaust grasses....

yes even hot it is getting two good streams of fuel out of the jets after it stalls out, but still won't start...... it attempts too..... but will only fire and spit the fuel back up in vapor form.....gas is vaporizing right in the carb or that's what it looks like to me...

Timmy

From: DaveVa78Chieftain
Sent: 8/4/2006 8:01 AM

Your description says yes, you have an EGR engine. The device by the thermostat housing is the CCEGR valve. The valve does not allow the EGR system to operate until engine temperature reaches 95 degrees. One hose goes to to the EGR amplifier mounted on the rear of the engine. The other hose goes directly to the EGR valve. The EGR valve is mounted on the left side (drivers side) of intake manifold just forward of the carburetor. The EGR valve is not on the carb itself.
440-3 did not use a heat riser valve however, many of the after market exhaust manifolds come with them. You have to block the spring on them open if you purchase one of those as a replacement.
There were many configurations of a TQ however, the vacuum port locations were basically in the same place across models. Some models had this one, others had that one sort of deal. Depended on emission control standards for the year and application.
Something about your statement 'Loads of vapor just steams right up out of the primaries' doesn't make sense to me. My understanding of typical vapor lock is that gas in the fuel lines gets hot enough to boil, turns to vapor and does not allow liquid fuel to reach the carburetor. Just as the water boiling point is raised in a sealed coolant system, the electric fuel pump is going to raise the boiling point of the fuel in the lines. Makes me wonder if you actually have vapor lock in the fuel lines.
A carburetor must have a method of venting the fuel vapors inside of it. If your evaporation control circuit (charcoal canister) has been disconnected, the carb may not have a method of venting the gases. It is possible the gas vapor would push the gas out of the fuel bowls. I bring this up because you said you did not feel you had the original version of the TQ (different vacuum ports). Some TQ's used an electric solenoid vent. Since your not sure what TQ you have, it is a possible problem source. The 413 engines used a holley carburetor which is internally vented so it is not an issue with them.
I just emailed some TQ info to you. Hope it helps.
Dave

From: MSN NicknameDaveVa78Chieftain Sent: 8/4/2006 8:15 AM
Then I would also suspect the ignition electronic control module and/or the ballast resistor. Electronics can do weird things do to heat. Component values can change do to temperature variations. Both carbs acting the same makes me question the control module even more. BooBoo had some odd isssues happen to him from a problem like that.

Dave

From: The_Handier_Man
Sent: 8/4/2006 9:45 AM

OK guys, I don't know why OLD ED has not thought of this yet, but this Winnebago is possessed. Thats right, no matter what you do, this thing will take over your life. If, and thats a big if, you ever get this thing running you will continue to have problems with it. Oh they might be small things like spots on the ground where it has been parked. Some black, green or even red ones will appear for no reason at all. Axles will break. And then when you think all is well you will hear sounds coming from deep inside. Oh they might sound like a power steering pump or even the brakes but beware. Have you ever noticed the smell of hot oil or coolant when it is running? That should be a clue. Have mysterious spots appeared on the ceiling? Are they in the shape of a cross? Trust me your troubles will not stop. I have researched this problem and found an answer. Please visit an EXORCIST at once. Here is one if you need help http://www.theexorcisms.com/ . Hey think of it. If Denision can't help we are SOL. Best of luck........................Les

From: denisondc
Sent: 8/4/2006 10:29 AM

I would offer to take it off his hands (for pocket change), but it is too new, too complex.
I worked on a 2nd cousins nephews 84 VW cabriolet; (a Mexican version) in Saltillo, Coah. Lots of space under the hood; no emissions gear at all, no canister, no EGR valve or air pump. Also no rust - Saltillo is in a high altitude desert.

From: Elandan2
Sent: 8/4/2006 12:48 PM

Maybe I missed something that you checked in the past but I would be inclined to think ignition. Have you tried a new ballast resistor? Pickup coil? The reason I say this is the fact that you say that the engine just shuts off. I would think that a carburated engine would do some sputtering before it quit completely if it was a fuel problem. The ballast resistor or pickup coil in the distributor may have a fault that breaks continuity when it heats up. Best of luck Rick

From: Cooneytoones
Sent: 8/4/2006 8:45 PM

Pick up coil brand new Axel....ballast resistor brand new, voltage regualtor brand new, ignition module new have a new ignition relay, but one on there is working OK for now. All the wire connections are tight most with brand new wire...alternator has 1k on it, bench tested last week OK....Spark plugs new, cap & rotor, new wires ....distributor has no play in it...plates are lubed and moving....timed it statically and then by light timing is tight on give or take a degree.....might be 8 BDC or 7 BDC but it runs like a race car till the heat builds up...and it does sputter so that what leave me to believe it is a fuel problem.....the EGR valve is non exitant....or at least I can't find it and I know it's supposed to be there....the vacuum amplifier is mia.....all that is to the left side of the carb is a little device looks like a dash pot....one of the hoses from the ccegr goes into it..is that the EGR?
Info you sent me Dave is very helpful...thanks....
Maybe I still will need an exorcist.....
Timmy

From: jbmhotmail
Sent: 8/4/2006 10:30 PM

Sounds like you have tried about everything ... have you tried heating up your electronics, one at the time, using an electric hair drier. I know everything is new, but you may have a bad component when heated, i.e. pick up coil, ballast resistor, voltage regulator, ignition module, etc. Hope this helps.

From: DaveVa78Chieftain
Sent: 8/5/2006 9:34 AM

As I said before, 440-3 EGR valve (implemented in 75 chassis year) would be mounted to intake manifold. Disk shaped vacuum chamber attached to a cast iron valve assembly that is bolted to the intake manifold. It is on drivers side, just forward of the carb (Just forward of the throttle linkage). There is a passageway from the head to the intake manifold for exhaust gases. The EGR valve recirculates some of the exhaust gases back into the intake stream. A common problem is carbon builds up on the valve parts resulting in the valve remaining open a bit. This condition acts like a vacuum leak (lean mixture).

Dave

From: daved27c
Sent: 8/5/2006 9:58 PM

Tim;

I have to admit that the last time I looked at this you were having a problem with the power steering hose. Now I see that your fuel starvation problem still exists. I also have to admit that my 413 doesn't have a EGR, a CCEGR,or a vapor canister, so I may be shooting from the hip but here goes. When the problem occurs, unscrew the fuel line from the carb.(As many times as you have had this apart it may have zippers on it). See if you get gas in the line after you unscrew it. This can be VERY dangerous, especially with an electric fuel pump. You have to come up with a way to SAFELY collect the gas so you do not end up with a "winnieflamego". If you have gas at this point then the problem is in the carb(s). (I doubt this is the case as it "runs like a race car" when cold). If not then the problem is before the carb. I would keep working back untill you find where the gas is getting boiled. Again you sould be VERY careful, unscrewing every connection, until you find where you have liquid gas . As always this is just my 2 cents.

Dave

From: Member_Administrator
Sent: 8/6/2006 6:30 AM

... "VERY dangerous"? No problem!... I volunteer to come over and do this! I survived one carburetor fireball which bounced off the ceiling of the DonorBago... just took a while to grow all my hair back... (But, I really think the problem is that you forgot to change out the winter air to summer air in your tires...)
[Grenade] - ExplosiveSob

From: Cooneytoones
Sent: 8/7/2006 7:56 AM

Did it and I wouldn't recommend you try this at home. The gas is boiling in the carb.......Have liquid fuel all the way to carb intake...As far a EGR goes..I know what it's supposed to do..still can't find any type of piping that goes from exhaust to intake manifold...unless it is under that little plate on the drivers side of the carb.....above that plate all that is there is a dash pot type valve that is connected to ccegr...nothing forward of the carb.....this is part of the problem I think '76 was the experimental year of the smogger carbs.....because all the info is till '75 and then '77 up....I've seen 4 different TQ carbs used in '76......PO pulled all the smoggers stuff off including most of the engine electronics......it did not have and alternator, nor was the voltage regulator hooked up and it ran (he kept wondering why the battery kept going dead)......the five way splice was a mess.....all that is redone, all electronics checks out fine with a multimeter, including the coil.......as far as heating up that individual stuff with a hair dryer......I don't think that they make a hair dyer that puts out that much heat.....Not for what this 440-3 is putting out heat wise...
I changed my winter air to summer air.....made sure non of the eletrical wires where kinked, the muffler bearing has been greased......and now the man at the parts store tells me I may need to grease my sphincter valve.......when will it end.

searingformyegrtimmy

From: The_Handier_Man
Sent: 8/7/2006 9:14 AM

Is the carb getting to hot? Is there a insulated spacer between the carb and manifold? Should there be one? Just another guess from me, Les

From: DaveVa78Chieftain
Sent: 8/7/2006 12:50 PM

First, the only EGR plumbing there is is the rubber hose routing. The porting for the exhaust gases are cast into the intake and heads. This 'heat' source (under the carb) is also used to warm the coil spring for the automatic choke. This approach eliminated the requirement for a heat riser tube from the exhaust manifold. The ports in yours might be plugged resulting in high heat carbon deposits under your carb.
Sounds like the PO removed the EGR valve and installed a blockoff plate. I just sent you an e-mail of what the EGR stuff looks like.
Far as I know, Dodge only used 2 TQ carbs for MH. A TQ-6545S (fed version) and TQ-9036S (Cali version). With that said, I also think Winnebago decided to only procure the California version of the chassis however, the EGR stuff would not been on the Fed version (possibly why there is a blockoff plate?). Then again, there may be fed versions out there. Still, you said you had a CCEGR valve so thats cali version. Other carbs you may have seen may be ones people have pulled from somewhere else (i.e off a car). That factory rebuilt one you have would be one that was made to fit multiple setups, not just one application (marketing approach).
The evaporator canister (vapor storage) was used on all rigs since 1973. It would be located passenger side, just aft of the radiator in the frame channel. Big black plastic cylinder around 8" long and 5" in diameter. 3 or 4 (year dependent) rubber hoses connected to it. Stores air from fuel tank and carb bowl when engine is off. Carb sucks it all out when you start the engine.

From: DaveVa78Chieftain
Sent: 8/7/2006 12:59 PM

It has been 2-3 years since I rebuilt my TQ, but I seem to recall there being a 1/8" thick spacer under it.

Dave

From: Cooneytoones
Sent: 8/18/2006 5:30 PM

Actually the spacer is about 3/4 or an inch......well so far so good......gas line can not get hot anymore....and I found the EGR valve stuck on open full........I eliminated the EGR for now.....Plugged and plated.....now it took some time, but the new electronic ignition modulate was also bad
the way I figured this out was: when it started acting up, I sprayed some CO2, from a can of stuff that frosts drinking glasses right on the electronic modulator, and it straightened right out...it cooled it off.............. far all seems as it should be......and then I replaced it.

I want to thank everybody for their suggestions and comments, and support.....

This is what CW is all about......no matter how far fetched....or whatever........being alone when multiple things GO WRONG, is a nightmare my brain will only think so fast, I get hung on"What the hell could it be." Without the help and support of all of you.......I'd still be saying, what the hell could it be.......thank you all

Timmy

From: DaveVa78Chieftain
Sent: 8/21/2006 7:36 AM

One last recommendation.
Please go buy the Dodge MH Chassis service manual for your chassis year. It will save you a whole lot of frustration. Thats were the EGR info I sent you came from (even though the book I have only goes up through 75).
http://motors.search.ebay.com/Dodge-Motorhome-Motor-home_Parts-Accessories_W0QQfromZR10QQfsooZ2QQfsopZ2QQsacatZ6028QQsamcmZ6028QQsaspiZ2QQsatitleZQ28DodgeQ29Q20Q28MotorhomeQ2cQ20MotorQ20homeQ29QQsbrsrtZd

75 and later chassis will most likely have EGR. The EGR valve sticks open (big vacuum leak) from carbon, dirt and/or bad EGR circuit and you get lean burn and hotter running engine. By law, elimination of the circuit is a no-no. Depends on where you live as to how much trouble it will result in. (Damn that PO ) Big city? you better have it working. Also, they have now started doing emissions monitoring (infrared beam) roadside (DC area for sure). Mostly at freeway on ramps. They measure exhaust gas, take a pic of your license plate and send you a notice to get it fixed if you get caught twice. If you do not get it fixed, you get fined. Please note, this is roadside as you accelerate on to the freeway. Not a pull over situation and test situation. States are required (federal mandate) to implement on the fly testing. Live in rural Virginia (no emissions test requirement), work in metropolitan Virginia? No matter, you still can get hit and fined. In fact, live in West Virginia, work in metropolitan Virginia? Still get fined. Because of federal mandate, it will expand nationwide over time. Technology validation phase is now over. It is now being implemented.
2nd lesson - Electronics can be affected by heat. Even new stuff can have issues (as the electronic module did in this case). Not a common problem with new stuff but can happen.

Dave

From: denisondc
Sent: 8/21/2006 11:26 AM

While I will agree that the original emissions equipment should be connected and working, I don't know that I would worry about it. My D22 winny has a GVWR of 13,000, so was exempt from emissions testing each time I renewed the registration in Fairfax County. I know this isn't the case in other states: Some have old-age exemptions, like California.
The EGR valve has mainly to do with limiting Nitrous Oxide formation. I wouldn't expect the roadside equipment to be able to check that, but I don't know for sure. Luckily my winnie predates EGR valves, only has a PCV valve. I expect to register it in rural Texas this winter.

From: Cooneytoones
Sent: 8/21/2006 9:10 PM

there is no emissions testing where I live in Indiana and there won't ever be.....at least not in this rual area.....You can still buy leaded gas for use on the farm through Farm Bureau...too many old tractors in these parts....And if they ticket me in another state well, than that's the last time I visit that state.....and they can come here and if they can find my place, well then maybe I'll write em a check.
I will eventually put it back to OEM over this winter, but right now, after doing all I did to it, and the price of fuel, the ten thousand things I have to do on the "honey do" list.....and winter time approaching, time and resources are limited for the rest of this year....even though I didn't get to do what I wanted to this year with the rig, I learned a lot....spent a bunch of dollars and days of time... it was very costly, both monetarily and emotionally....but what I learned here on CW...... Priceless....

Timmy

From: Cooneytoones
Sent: 8/21/2006 9:42 PM

I have the manual and mine goes from 73 to 77.....that is part of the problem......'76 was the year of experimental changes for the emissions systems.....and the TQ carb used was changed several times during that production year from what I found out, some had 75 partial smoggers and others used what would become the 77 full smoggers..and that most experts will tell you that they ruined the TQ when they went to smoggers...especially rebuild ones, and without knowing what the PO did, or what this had on it when new, it's kinda like a crap shoot... the TQ they show in my manual is different from the one that was on there (and is on there now) and different form the rebuilt one from what the book says is supposed to be there.....all the ports except the pcv valve are different and in different places, and there is more and less ports on all three...
Your specks on the ES is real close to what this rig had, I know my rig wasn't a California model, it was a Federal, originally sold in KY when new, but in 76 the Federal model started adopting some of 75 Calif. Some minor changes to the air horn and the location of the ports, so I have to just keep playing around till I find the right combo of things....I'd like to see one first hand and up close, but haven't been able to find one in a bone yard so far, but I am looking.... but to tell you the truth....the Edlebrock is looking better now than it was about 3 months ago.

Timmy

From: mightybooboo
Sent: 8/23/2006 2:31 AM

California only has the 1965 or prior exemption on smog,anything else its smog for life,thanks to Arnold.

BooBoo

From: ClydesdaleKevin
Sent: 8/24/2006 8:48 AM

Gotta love registering vehicles in Florida! You only pay personal property taxes ONCE, when you first register the vehicle, and then you never have to pay taxes on it again! And that applies to any vehicle, even the most expensive new motor home! Also, there is NO emissions, and NO inspection, on ANY vehicle, EVER! Florida sucks, but its a great place to register an RV!

Kev
[Kilt]

From: jbmhotmail
Sent: 8/28/2006 11:12 PM

I ran across an article that may help, not sure if applies to your problem. A guy stated that his engine is difficult to start when hot, he has to crank for quite a while and it acts flooded, choke is open. The reply was: Progressive carb float failure is a problem with the Carter ThermoQuad which is caused by fuel saturation of the plastic float in the fuel bowl. The condition is indicated by a gradual reduction in mileage, stalling after abrupt starts and hard starting of a hot engine. At 25K to 30K miles (approx 2 to 3 years) these floats should be replaced. When installing the new float, lower the float level setting 1/32 inch below the factory setting. Inspection of the original float will not indicate an obvious difference. Generally the weight difference caused by soaking of the fuel into the plastic will be very small and hard to detect. If you are already using a brass float, remove it and shake it to see if you can hear any gas slouching around from a pinhole leak.
Good luck