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Mopar Quadrajet ?? #1406266
03/21/13 10:05 PM
03/21/13 10:05 PM
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Freeport IL USA
poorboy Offline OP
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We picked up a Quadrajet off an 82-85 5th Ave to use on a different project.
That carb has an electronic operated bowl vent, but we are running a simple carb & electronic ignition, with no computer. Is the electronic bowl vent going to give us problems? Will everything still work if I ignore the stupid thing? Can I bypass it, and if so, how?
Gene

Re: Mopar Quadrajet ?? [Re: poorboy] #1406267
03/22/13 02:36 AM
03/22/13 02:36 AM
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Granite Bay CA
Kern Dog Offline
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I thought that the Mopar Qjets were like the Chevy ones in function. Some had a fuel enrichment solenoid for cold start, but otherwise they worked like any older Qjet.

Re: Mopar Quadrajet ?? [Re: poorboy] #1406268
03/22/13 10:26 AM
03/22/13 10:26 AM
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Chicago illinois
ChinooK440 Offline
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I think what your calling an electric vent MIGHT be a mixture control solenoid which would be an electronic feedback carb. that needs a computer and associated sensors etc. to run correctly.

Re: Mopar Quadrajet ?? [Re: ChinooK440] #1406269
03/22/13 11:07 AM
03/22/13 11:07 AM
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Florida
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scratchnfotraction Offline
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Quote:

I think what your calling an electric vent MIGHT be a mixture control solenoid which would be an electronic feedback carb. that needs a computer and associated sensors etc. to run correctly.






it may have the mettering needles that get a pulse/noid for the idle mixture.

IMHO,I would grind the shaft and remove the mopar throttle lever,find a older chebby carb from a 327/350, weld the mopar throttle lever onto the chebby carb throttle shaft.

this way all of the mopar throttle linkage/TV linkage hooks up correctly.

I am running a 1974 chebby q-jet on my roller cam 318 in the 85 truck.

hugh jorgan sent me a newish 1905 edelbrock q-jet/thermobog replacment carb for 72-85 dodge truck with 360/400/440(they dont make them any more) which is awsome with a working elect choke.

it shows a mopar throttle adaptor in the owner manual for it,but the lever looks almost identical to the mopar lever I use.

I just put the stock throttle stud in and it all adjusted out great with the stock throttle bracket/1-piece rod TV linkage for the mid 80s trucks.

do you have the intake bracket with correct rod/trans lever?(I have 2 set ups if you need one)

I have a few q-jets that I grabed up for future mods to fit mopar.

Re: Mopar Quadrajet ?? [Re: ChinooK440] #1406270
03/22/13 05:14 PM
03/22/13 05:14 PM
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Indiana
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Fury Fan Offline
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Quote:

I think what your calling an electric vent MIGHT be a mixture control solenoid which would be an electronic feedback carb. that needs a computer and associated sensors etc. to run correctly.



with this and Scratchin'.
If that truly came off a 5th it wasn't the original carb, OEM was T-quad until '87 I think, then was feedback Qjet with spark and fueling computer (often mis-named as Leanburn).

Either way, I don't think 5ths ever got a 4-v, I think later ones of the feedback era got electronic Holley 2-barrels.

So, figure out for sure what you have and what that solenoid is. If it's a GM carb it could be from teh early 80s and with a solenoid bowl vent or something.

Re: Mopar Quadrajet ?? [Re: Fury Fan] #1406271
03/22/13 05:35 PM
03/22/13 05:35 PM
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dogdays Offline
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No late model Fifths with a 4-barrel.

There is another thing that GM did with the Q-jets and the electric valve. On some they used it to block off a p[ortion of the float bowl for evap emissions, I believe. You really don't know until you take it apart.

There is a number on the back of the carb, each Q-jet had a code. Look online for decoding quadrajets and you'll see what I mean. I recently bought a raft of high altitude and California emissions Q-jets for mileage work in the mountains. Once you learn the code it's all downhill.

SFT, the Edelbrock Q-jet is a choice piece, I have bought three over the years, cheapest one was something like $80. The most expensive one was like $120. It looks to me that Edelbrock started out with regulation Rochester bodies.

R.

Re: Mopar Quadrajet ?? [Re: dogdays] #1406272
03/22/13 07:47 PM
03/22/13 07:47 PM
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NW IL
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Biggie Offline
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Here is a internet pic of the carb we have. We need to know what the blue plug in goes to


"Think of all the Ford owners who will someday want an automobile." John Dodge

57 dodge sierra wagon
03 chrysler 300m
10 dodge charger
Re: Mopar Quadrajet ?? [Re: Biggie] #1406273
03/22/13 09:03 PM
03/22/13 09:03 PM
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Florida
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scratchnfotraction Offline
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IIRC that blue plug is the noid for pulsing the metering needles.

IIRC I have a carb in the shed that is apart. i will go take a pic of the inside of one.



dog,the edelbrock 1905 were new casting to start with.it works like no other q-jet I have had. the choke works,its not worn out, and it was FREE!!

wow! what a kick it has on the 440 over the 600 eddy carb.

Re: Mopar Quadrajet ?? [Re: scratchnfotraction] #1406274
03/22/13 09:06 PM
03/22/13 09:06 PM
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Granite Bay CA
Kern Dog Offline
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Quote:



..... in the shed that is ....




I have read many, many references to this " shed ". I'll bet it is huge!

Re: Mopar Quadrajet ?? [Re: Kern Dog] #1406275
03/22/13 10:53 PM
03/22/13 10:53 PM
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Florida
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scratchnfotraction Offline
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Quote:

Quote:



..... in the shed that is ....




I have read many, many references to this " shed ". I'll bet it is huge!




it has been called a magic shed in many GGA post as well.

here is the old one after the oak tree fell and was removed from top of it. good thing the 440 truck was out of the way.

Last edited by scratchnfotraction; 03/22/13 10:59 PM.
Re: Mopar Quadrajet ?? [Re: scratchnfotraction] #1406276
03/22/13 10:58 PM
03/22/13 10:58 PM
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Florida
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scratchnfotraction Offline
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here is the new replacement shed. 12x20

7636633-tailgate#4.jpg (350 downloads)
Re: Mopar Quadrajet ?? [Re: scratchnfotraction] #1406277
03/22/13 11:31 PM
03/22/13 11:31 PM
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Wills Point, Texas
Hugh Jorgan Offline
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New shed needs more "stuff"....
I have an idea...

Re: Mopar Quadrajet ?? [Re: Hugh Jorgan] #1406278
03/23/13 04:20 AM
03/23/13 04:20 AM
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Not2farfromNashville, TN
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Rug_Trucker Offline
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The truck Mopar Qjets don't have all that crap on them. I pulled one from a 86 van. My van engine came with a 87 Qjet.


"The only thing to do for triumph of evil is for good men to do nothing"

"NUNQUAM NON PARATUS!"
Re: Mopar Quadrajet ?? [Re: scratchnfotraction] #1406279
03/23/13 08:34 AM
03/23/13 08:34 AM
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Cincinnati, Ohio
Challenger 1 Offline
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Quote:

here is the new replacement shed. 12x20




I think I see a sink hole opening up?

Re: Mopar Quadrajet ?? [Re: scratchnfotraction] #1406280
03/23/13 08:34 PM
03/23/13 08:34 PM
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Piqua, Ohio
dodgeram440 Offline
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Quote:

here is the new replacement shed. 12x20




That's the shed on the left, right? Has to be to be big enough to hold all your goodies.

Re: Mopar Quadrajet ?? [Re: dodgeram440] #1406281
03/25/13 02:08 PM
03/25/13 02:08 PM
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dogdays Offline
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To the OP: Do a basic Google search for "quadrajet identification" and you will find more info than you can use.

To SFT: I will look at my Edelbrock Q-jets when I get home tonight and see where the body casting came from. Maybe they were produced by Weber, or maybe by Rochester.

R.

Re: Mopar Quadrajet ?? [Re: dogdays] #1406282
03/26/13 10:22 AM
03/26/13 10:22 AM
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QuickDodge Offline
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I believe 1986 was the first year Mopar used the computer controlled Q-jet. It was used on the Grand Fury and Diplomat police cars and maybe other models. I don't know if that carb was used on the 5th Avenues.

I've wondered if the mixture control valve in one of these computer controlled carbs could be manipulated to make an engine run lean to improve gas mileage? I worked on one of the ex-police cars years back that had the computer controlled carb. That car was running full rich and getting single digit gas mileage. I don't know how an engine would perform if the carb was stuck at full lean. If driveability was acceptable it may get great fuel mileage.

Re: Mopar Quadrajet ?? [Re: QuickDodge] #1406283
03/26/13 10:27 PM
03/26/13 10:27 PM
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Posts: 10,486
Freeport IL USA
poorboy Offline OP
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The old guy we got the Quadrajet from said it was off a "Police Interceptor", but then everything he had was off a Police Interceptor. The number crosses over to an 82-87 Dodge & Plymouth 318 car.
It is the feedback carb, (picture posted earlier) and we intend on using it on my son's 331 Hemi. I would like very much to figure out a way to make this thing work. I would not be opposed to having it "stick" at the midpoint between rich & lean, if we can determine how to go about that. The carb looked pretty good, and I put a kit in it, but must have messed that up because we have a loud whistle at idle. I'm going to pull the carb back off and see if I can find the whistle problem, I'm hoping its not throttle bushings. Gene

Re: Mopar Quadrajet ?? [Re: poorboy] #1406284
03/27/13 10:55 AM
03/27/13 10:55 AM
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Fury Fan Offline
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To use that carb the first question we need to answer is:
Does that solenoid need a PWM signal or a varying-voltage signal to operate as the OEM intended???

If PWM, you'd need a special module to make that work.
If voltage, a simple potentiometer would work.

Either way, you'll need some way to monitor the adjustment vs AF ratio. But I guess if you use the adjustment only on the highway, you could simply lean it out until it starts to misfire.

To make it automatic, a vacuum switch of suitable range could be wired to trigger a relay that energizes the 'noid circuitry. Might not be real smooth when it kicks in/out, though, but a 'car guy' might find that to be useful feedback.

Re: Mopar Quadrajet ?? [Re: poorboy] #1406285
03/27/13 11:42 AM
03/27/13 11:42 AM
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Not2farfromNashville, TN
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A whistle maybe the throttle shaft. When the shaft gets sloppy, the butterflies hang up onthese carbs.


"The only thing to do for triumph of evil is for good men to do nothing"

"NUNQUAM NON PARATUS!"
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