choke question

[rhyno811]

i have a 87 monte ss. every morning when i go to start it the idle goes upto almost 3000 rpm. i tried adjusting the choke and it just wont go down. eventually after it gets warm ill step on the gas and hear a backfire and it goes down to 1000 rpm. the car is all stock and the carb is rebuilt. im car savvy but i've been out of the v8 seen for awhile. can anyone help?

 

[pontiacgp]

Have you checked your timing and the advance mechanism?

 

[rhyno811]

dont think its the timing cause after it warms up it idles fine... what advance mechanism??? on the carb? i dont know where it need to be set.

 

[pontiacgp]

the advance mechanism in your distributor but since you don't think it could be the timing then don't bother checking it....good luck

 

[foxtrot]

Do you have the stock quadrajet automatic choke? If so, why not just try to replace it with a new one?

 

[rhyno811]

Do you have the stock quadrajet automatic choke? If so, why not just try to replace it with a new one?

replace the carb or the choke? the carb was just rebuilt in the past 6 months. all parts are new. i just got the car a couple weeks ago, and im kinda learning all over again

 

[Uncletruck]

Even on the electronic carbs there is a fast idle adjusting screw on the carb to change the speed, adjusting the choke will only control the amount of time the choke remains closed, not the fast idle speed. Look on the linkages with the engine cold and shut off. If you open the throttle to allow the choke to close, you'll find a stop screw that contacts a small cam that controls the amount of throttle opening with the engine cold. That cam moves in steps as the choke opens, and the slow idle speed once the choke is fully open is controlled by the electric solenoid. But when the engine is cold, the fast idle speed is all mechanical.

If that adjustment does not slow it down, I'm going to venture you have an air leak in to the intake manifold somewhere.

-UT-

 

[Phoenyx]

^^ what he said ^^

 

[go3and88]

I too was going to say fast idle screw.

 

[patmckinneyracing]

....eventually after it gets warm ill step on the gas and hear a backfire and it goes down to 1000 rpm. the car is all stock and the carb is rebuilt. im car savvy but i've been out of the v8 seen for awhile. can anyone help?

Now I agree with it possible being the fast idle screw requiring adjusting. But at the same time, if your car is back firing that's normally an indicator that your timing needs to be adjusted. Plus if the timing hasn't been checked, being that your running a 24 year old stock set up, than you might want to just check it anyway just for safety sake. Good luck and let us know how it turns out.