OK, my 84 Z28 H.O. had no choke assembly whatsoever. I replaced the carb with a rebuilt Quadrajet E4ME. Hooked up the heater wire and everything.

Start the car and it idles around 2000rpm. Which I am assuming is the fast idle. The choke butterfly opens up and is fully vertical, and the car still idles at 2000. I tap the gas and then it will idle at 2000 again and just die.

I restart the car without giving it gas...it idles at 2000 for a few seconds then dies. When the car dies, the choke light and check engine light come on. Start the car back up and the lights go off.

What could be the problem? It starts when it's cold but when it's warm it just wants to die. I drove it earlier and it died right in the middle of the street and I almost got hit because it wouldn't start back up. I sat there in the middle of the street for 5 minutes and the car finally started back up. On the way home I had to keep gassing it, even when braking because it idled so low then would die.

 

The choke light will come on while the ignition is turned on, and the alternator is not charging the battery, ie. when the engine is stopped. That's normal.

Check for anything in the linkages binding that's keeping your throttle blades from closing.

 

The butterfly closes when I push the throttle when it is cold. When the car is warm and I push the throttle, it just stays open...which I assume it is supposed to??

Anyways, my problem is that it is warmed up fully and it idles for a few seconds at 2000rpm then it will just die. Do I have to mess with the fast idle screw or?? I don't think the fast idle screw would do much...

I was under the impression that the car was supposed to go into normal idle once the car warmed up...but maybe I am mistaken. Even when I push the gas, it will idle at 2000rpm then it will die. So I have no idea.

 

Im not sure what your problem is, but it is supposed to go to normal idle once the car is warmed up.

 

Whoa whoa, are you the same guy who had this identical problem with the previous Q-jet?
And with a new Q-jet, it does the same thing??
Check your timing, you might be really far advanced to get a 2000RPM idle speed.

When idling at 2000RPM, is the throttle stop resting on the hot idle screw?

 

No, it is NOT the same problem.

On the old choke, it would idle at 1500 continuously.

On this one, the choke warms the engine up at 2000rpm and then if I tap the gas, the engine will die. If I restart the car, the engine will die.

I put the old carb back on this morning and messed with the idle screw and also sprayed a lot of carb cleaner into it. I got it to idle at around 900 or so. Sat there idling for 30 minutes with no problem. Drove it no problem...stoplights no problem.

Never let it get fully cold then start it back up, so I'm not sure how it'll do. Guess we'll see in the morning.

 

oh, whoops, my bad.

Ok, old carb then, works good now? I guess see if it'll do a cold start ok. You said it has no choke right? What happened to the choke??? Cut off? There should be the front vacuum break and the black plastic choke thermostat, with a green wire going to it. Which (or all?) are missing?

 

Sounds pretty simple & obvious to me.

Your curb idle is set too low. When the choke is on, the idle is controlled by the fast idle cam, which makes it idle at what you describe as 2000 RPM.

Then when the choke comes off, the curb idle (if the engine could run at that speed....) would be 300 RPM or whatever, instead of 750.

Try turnign the curb idle screw in one turn and repeat your test. Repeat until you get 750 RPM; or 625 in gear; or whatever you use.

Don't trust the dash tach. Use a piece of REAL test equipment, until such time as you've verified the dash tach accuracy against an actual instrument.

 

I agree, when cold it runs at high idle because of the high idle cam. Then when it is warm it kicks down to too low of an idle to keep it lit. the reason it is restarting and idling at the 2K for 7 seconds or so is because Idle load comp. on the side of the carb. it will bump out on initial start up and pull in once the motor is lit. then it pulls in and she dies.

I have a similar problem but after running on at highway speed for a while, it will jam out and not pull back in... so I unplugged and removed it from the car. Problem solved.

 

The old carb is on my car right now. It needs to be gassed when I first start it up cold, because it has no choke. It has no vacuum break, nothing. I found the green wire that goes to the choke, and I hooked it up on the NEW carb when I had it installed.

The old carb is in there right now like I said and it idles around 950 (according to the dash)...so I guess all is well now. Maybe taking it off and putting it back on did something.