Advice on ThermoQuad Vacuum Lines & Electrical Wiring

[Medtech71]

Sent: 10/18/2004 3:58 AM

Hello fellow happy campers, my name is Steve and I recently purchased a 77 dodge brave (winnie) with a 440-3 engine, thermo quad carb, model M30.  I am in desperate need of where all these open vacum lines and electrical wires connect.  Any kind of help will be appreciated.  Thanks everyone, Happy Camping

steve



From: HeavyHaulTrucker
Sent: 10/19/2004 8:39 PM

Steve, I believe that I have the sister to your rig -- I also have a '77 Brave 21' with a 440-3 & a ThermoQuad.  I recently rebuilt the carb on it, so I can give you the exact information you need.

To start with the short vacuum lines:
1 goes from the small vacuum port on the front-left of the carb base to the distributor vacuum advance.
1 goes from the small vacuum port on the back of the carb base to the dashpot mounted on the right-rear corner of the carb.

Now, the longer, larger vacuum lines:
1 comes off of the large vacuum port on the intake manifold behind the carb and goes to the brake booster. 
There is a small port coming out of the side of this fitting that goes to your cruise control module (if you have one).
1 comes off of the large vacuum port on the front-center of the carb base and goes to the PCV valve.
This line has 1 Tee fitting for a small vacuum line that comes up through the engine cover and goes to your vacuum guage.

This is about it; these are the stock lines that they were originally built with.

John



From: Sea Hag
Sent: 10/20/2004 9:10 AM

Most of the vacume lines go to the emmishion system  , with the exception of the vacume advance and cruze controll if so equiped . The electrical connections went to a electronic speed sensor  to control a vacume trottle linckage damper . All of the componants were removed and MIA when I got my 76 w/440 and California Emisshion package . I may be able to send you some info . Email me - Sea Hag 



From: Sea Hag
Sent: 10/20/2004 9:23 AM

John - Yours seams to be missing some compomants too if it's a 77 . Like the EGR valve and fuel evaporator canisters . Your brakes are also modified if they are vacume boosted . Dodge went to HydraBoost system in 76 useing the power stearing pump to boost brakes . The 76-77 Dodge MH Chassis service manual does not cover the Vacume boosted HydroVAC system . and the chassis parts catalog does not list vacume boosters past 1975 . Sea Hag 



From: Sea Hag
Sent: 10/20/2004 9:44 AM

Let me correct myself , The M300 Chassis still used a single Vacume booster . and the M4, M5 & M6 went to the Hydro Boost after 76 . Sea Hag 



From: HeavyHaulTrucker
Sent: 10/20/2004 10:09 AM

Sea Hag, there is no EGR valve on mine... however, the chassis year for mine is 976.  Maybe this was only a California requirement, but mine was originally sold in Colorado and has passed emissions testing there every time without one.  Either way, though, my engine plumbing is dead-bang stock -- has never been modified.  Everything except the spark plugs is original (in fact, I had to replace all of the vacuum lines the other day because they had deteriorated so badly).

John



From: Sea Hag
Sent: 10/21/2004 9:45 AM

John - I just reviewed the emisshions section of the service manual 76-77 - There should be a EGR to the left of the carb on the intake manifold ( it 's not very big kinda hard to see  tucked under the linkage )the Egr is controlled by a coolant temp . vacume valve on the water manifold by the therrmostat .    My chassis was completed by dodge in 02 / 76 .  Although it was originally sold in Peroria , IL.  it was built on a chassis set up for sale in California . According to the manual The California pakage has the Fuel Tank  Evaporator system ( Charcoal Canisters ) . Plus the standard heavy durty emmission system , the EGR and PCV valves No emiisshion air pump.
   None of this is currently hooked up as some stuff is MIA . It did pass a emisshion test last spring  without it . I do plan to install the fuel evaporatorcanisters I got from a 1975 donor chassis as it's the only vent for the Fuel tanks . The rear tank will form a vacume and act like it's out of fuel if I don't leave the filler cap loose . Sea Hag 



From: HeavyHaulTrucker
Sent: 10/22/2004 3:31 AM

Sorry Sea Hag, no such animal on mine.  There isn't even a provision on the manifold for any kind of a valve at all.  There is no valve near the thermostat, either.  It is funny, though -- when I worked on Brenda's winnie, which is almost a clone of mine, I compared everything to see the differences between the two model years.  Hers has the canisters, but does not have the EGR.  Hers is undeniably completely original (except for the passenger side exhaust manifold, which she had replaced) -- she bought it from one of her neighbors, who had bought it brand new and had never done anything more to it than normal maintenance before they parked it several years ago.

You know, I have a theory about this... remember back in "the old days", everyone kind of looked at emission equipment as a bad joke.  I wonder if a few chassis managed to sneak out of the assembly plant without all of the emission equipment?  I have noticed that several other older vehicles from that era are also sort of "spotty" on the presence of some of the emission equipment on equipment that is undeniably all original.  This is just a theory, but I don't have any way to prove or disprove it.

John



From: Sea Hag
Sent: 10/22/2004 8:27 AM

John , Yes it is strange , some chassis had emisshion systems and some didn't . Mainly around 75-77  before it became consistant .the service manual notes on many componants                   ( If  Installed ) . Mine at one time had all of the componants for California Standards but most of it was MIA from PO's , took a while to figure out what all the abanded wires and hoses and lines were for . Ive been told that the system used wasn't dependable , a mechanic freind called it a failed system .  Guess they were still experimenting  .  I intend to use some portions of it mainly the fuel canisters to properly vent my tanks and hold in some of the fuel vapor and the electronic speed Switch and vacume damper to hold the carb open a little momentarily when rapidly decelerating to keep exaust from loading up with unburnt fuel . then work in the EGR once everthing is working properly . I don't intend to replace missing the vacume amplifier as this was one of the componats that had a design flaw . It passed a emission test ( just an idle test in Illinois ) as it is , with nothing hooked up as it doesn't use them at idle . Just suprised the test guys didn' see the canisters were missing from thier frame mounts . Sea Hag 



From: nitedriver57
Sent: 10/24/2004 12:27 AM

Hello All:
I'm called nitedriver and am somewhat new to this forum (about 3 weeks). I recently purchased a 1977 WD26RT on a dodge M400 chassis with a 440-1. I have just fixed all the leaks, and after last nights rain I am now confident they are fixed. I am learning alot here and would like to help anyone if I can. Since this is my first posting I will be brief.

There are basically 2 types of emissions controls. The differance being no EGR then federal specs, if EGR is present then CA emmisions controls. The EGR valve is about 1/3rd the size of most I have seen and is located near the front left corner of carb. (to verify EGR is operational, disconnect vacuum line from engine and apply vacuum yourself. At an idle this should cause the engine to just about stall out.
A few notes:
2 fuel tanks = 2 evap canisters, on some units I have seen a larger vent line from the fuel bowl vent on the carb to one of the evap canisters, on some others the vent line may go to the air filter housing.
The solenoid controlled vacuum valve on the right rear area of intake manifold just in front of the vacuum ampifier, has what appears to be a vacuum port disconnected, this must remain so. It acts as the delay valve for the EGR to prevent stalling etc from EGR opening too early. New there was and should be a small foam type filter on the port which gives the appearance it is plugged, after a while the heat, fumes and such cause this filter to "dissolve".
In CA, missing or improper routing of vacuum amplifier or evap canisters will cause a failed test.
I do have various vacuum diagrams and emissions component requirements, specs with some adjustment procedures if it will help anyone. E-mail me and I can scan and send. It may take a day or two for me to respond but I will.
Well back to my re-wiring of the dash and wiring harness.

Nitedriver



From: Sea Hag
Sent: 10/24/2004 10:13 AM

Nightdriver - Welcome aboard and thanks for that info . there is a good diagram and explination in the 76 dodge MH chassis service manual , emissions section . I have that in Jpeg format off my Cd version , if anyone needs it . I have to email them one page at a time as they are large files . I'll keep you in mind if I ever find an amplifier and deside to use it . My main consern is the evaporator caisters at this point , as currently the aux tanks is venting at the front of the chassis ( not a good thing for a MH with open flame pilots for appliances . . ) and the main tank vent is pluged off  causing that tank to form a vacume . I do mow have a set of canisters I got off a donnor chassis and have been told I can reroute them and use them without the ampifier . Some PO's just took alot of this stuff off without realizing the consiquence .
    You may want to check your engine code ( it's stamped on the top of the block , drivers side , next to the front corner of valve cover ) Most of these MH 440 are 440 3  . it does mention a 440 1 in the manual  but just brefly in identification section . all specs for the 440 in the manual are for a 440 3 . I think there is also some mention of the 440 1 on the valve cover emisshion specs sticker . there have been a couple of post where members have a 440 1 but I'm not sure if it's verified and there are very few .  It's worth checking into - Sea Hag