what carb to get next?

[powerinit]

My dad's (soon to be mine) 1986 caprice w/ the 305 4bbl rochester quadrajet im guessing? We're probably gonna do something with the carb, cause it's in rough shape. My question is, should I just get it all rebuilt, fixed up or buy a new one? if get a new one, which would be best in anyones opinion? what kind of functions would the carb need to work on the car or is there anything special needed function wise? gotta keep the beast runnin good (too many of those ppl around here with ricers or big rims ) so any help is appreciated

[silicon212]

Originally Posted by powerinit

My dad's (soon to be mine) 1986 caprice w/ the 305 4bbl rochester quadrajet im guessing? We're probably gonna do something with the carb, cause it's in rough shape. My question is, should I just get it all rebuilt, fixed up or buy a new one? if get a new one, which would be best in anyones opinion? what kind of functions would the carb need to work on the car or is there anything special needed function wise? gotta keep the beast runnin good (too many of those ppl around here with ricers or big rims ) so any help is appreciated

You're very limited in what you can put on it - the E4ME Quadrajet is the only carb that can legally be used on that car, due to the OBD system onboard. I'd rebuild what you have - when properly set up and tuned, that carb is just fine. A new one would set you back close to a grand, and the rebuild kit through Autozone is about $40. Big difference.

If you do decide upon a different carb, you will need a replacement distributor with a vacuum advance, and you will need to cut the computer out of the car.

[powerinit]

guess im rebuilding then. would you happen to know if the rebuild kit would fix the high idle cam from sticking on the carb (high idle cam lever)? I think that may be the cause of the car's dieseling prob.

[silicon212]

Originally Posted by powerinit

guess im rebuilding then. would you happen to know if the rebuild kit would fix the high idle cam from sticking on the carb (high idle cam lever)? I think that may be the cause of the car's dieseling prob.

It could be the bushing surface for the throttle shaft, causing it to stick a little bit. The only thing you really need to do to the curb idle cam is clean it well and make sure it doesn't stick, and then properly adjust it. Adjust the choke pulloff too.

[capriceforever]

Before you dive into carburetor work, there's a few things to check if you have a dieseling / run-on problem.

1. Make sure the curb idle adjustment screw (front/bottom/RHS of carb) isn't holding the throttle open after you take your foot off the gas. ON the off chance someone messed with it.

2. "If" you're car is an Olds 307, it might have an anti-dieseling solenoid. Not sure if the 305 has that. BUt my Olds 307 engine was running on cause of a tiny tiny vacuum leak in a hose that went to a vacuum holding tank. The dieseling solenoid is supposed to cut vacuum to the throttle kicker (top RHS of carb) so the throttle releases completely when shut off.

3. If your car has a lot of city driving, try top-engine cleaner (at night when no one is around....not next to a school ground during the day.... uh hum). Carbon buildup could cause run on, more so when the engine is hot.

If ur fast idle cam is sticking, try some carb cleaner to clean off any deposits that might be causing it to bind.

My best guess is that more than half the carb replacements people undertake don't solve the problem they set out to remedy, because the carb wasn't the problem. I would leave the carb to the last thing to fix.

And of course, check your vacuum hoses for leaks. Very difficult to tune an engine wtih vacuum leaks. A vacuum leak can cause lots of downstream problems that might not be obviously related to vacuum.

Good luck.

[GreyGoose006]

A word of advice, if you decide to rebuild, make sure you take out the Throttle Position Sensor pin. it is about 5/8" long and easy to miss. you DONT want it to get into your engine as it did on mine (DOH).

[powerinit]

last time I checked the high idle cam lever, I pushed it down and it came up slightly, it wouldn't stay ALL the way down, unless it's not supposed to. One day my dad came home and the idle was stuck up, so I saw the choke closed a bit, pulled it open and the engine went down a little. Then as a experiment type idea, I pushed the high idle cam lever down when my dad shut it off and it shut off with little to no resistance. The previous owner is the one who told me it should get a carb rebuild, but i'll hold till i'v checked your advice, thanks guys and anymore advice or anything would be nice.

[silicon212]

Originally Posted by powerinit

last time I checked the high idle cam lever, I pushed it down and it came up slightly, it wouldn't stay ALL the way down, unless it's not supposed to. One day my dad came home and the idle was stuck up, so I saw the choke closed a bit, pulled it open and the engine went down a little. Then as a experiment type idea, I pushed the high idle cam lever down when my dad shut it off and it shut off with little to no resistance. The previous owner is the one who told me it should get a carb rebuild, but i'll hold till i'v checked your advice, thanks guys and anymore advice or anything would be nice.

Sounds in that case that you have a maladjusted choke. You can loosen up the three screws on the side of the choke, move it a little in the direction of less resistance (can't remember now, think it's clockwise) to lean it (the choke) out a little.

[powerinit]

would these problems relate to the car usually stalling a few secs after startup, almost everytime? (unless you floor the pedal to keep it up) second time you start it, it starts and runs perfectly fine.

[silicon212]

Originally Posted by powerinit

would these problems relate to the car usually stalling a few secs after startup, almost everytime? (unless you floor the pedal to keep it up) second time you start it, it starts and runs perfectly fine.

Do you see black smoke when you first start it up?

If so, then the choke could definitely not be letting air in at the proper time. Do you have a check engine/service engine soon light? Causes of the choke could be a failed/maladjusted choke, or a bad vacuum pulloff.

[bobss396]

Look for a local carb shop that can redo YOUR carb for you. It will probably run about $250 since it has a couple of electronic parts in it. I had one done a few years ago, I brought the carb in, got it back within a few days. It worked great, the price included tuning the carb after installation.

Bob

[Cyrix_2k]

Originally Posted by powerinit

would these problems relate to the car usually stalling a few secs after startup, almost everytime? (unless you floor the pedal to keep it up) second time you start it, it starts and runs perfectly fine.

lol, my car does that and it's fuel injected. It only happens when it's cold. Also, when the two back spark plugs were replaced it stopped for a while.

Does your car miss / run rough sometimes by any chance?

[powerinit]

The car runs pretty much perfect besides the others problems i'v been asking about. no misses (gave it a tune up about 2 months ago) and no smoke ever. The check engine soon light is usually on, but thats normally after a couple miles of driving. My dad had to rev it 3-4 times the other night to get it to idle down (the first night in a long time its ran kinda rough) but it was night and cold so. I think we'll have the garage do it as it needs an inspection and new rear shocks/ springs next month newayz.