carb trouble? a bit long

[ilikemud]

i am not too sure what the deal is here, but when first start my truck it misses spits sputters and idles like it has a huge cam... not to mention smokes a decent ammount. but after 3 or 4 minutes the idle smooths out and the truck runs like a top. no smoke no problems. the engine is a tbi 350 out of an 89 with 120,000 miles on it. all stock except for a high flow oil pump and new valve seals. the computer was messed up so i just converted it to carb... the only carb i had was a mid 80's q jet (many electrical connections not hooked up) choke and secondaires both work. ?could i be having a problem due to not needing the electrical stuff since my truck is a 78?? any help please!!!

 

[diesel4me]

I am not an expert at the newer quadrajet carbs(electric ones)but I know if you dont hook the wires up(put it on an older non computer application)it will run rich--I think the fuel mixture is controlled by a soleniod inside the carb(thats where the wires go that come out of the top of the airhorn.Someone on here will probably have "been there and done that"and will be able to help you more.There may be a way to run the computer carb on the older trucks--I dont know for sure. /forums/images/graemlins/dunno.gif

 

[dyeager535]

Ditch that carb, and get one that isn't computer controlled.

You said numerous connections, so if it has a 3 pin connector on the drivers side, you need to replace it.

CCC carbs run full rich in the "fail" mode, so economy is horrible but the vehicle runs pretty much fine. (but very "sooty" exhaust)

I never had a problem with mine on startup when the CCC ECM failed, but I can see how it would...if the carb goes to fast idle, the throttle plates are cracked open, and it is probably getting lots of fuel from the "primary" side and not the idle circuit alone.

 

[ilikemud]

yea, that seems to be the one i have on there... crazy gm and their need for computer controled everything... o'well looks like i am getting the 74 q-jet rebuilt, unless anyone know how to trick the sensor with out actually putting in the computer???? oh yea thanks for the help..

 

[dyeager535]

No way even remotely easy to trick it...the solenoid pulses the primary metering rods, so it's not in a constant state.

You can't convert them to the non-CCC setup either, since the primary rods are entirely different from all previous Q-jets.