I'm working on my 83 Z28 camaro (305/5spd) and I'm having a heck of a time trying to get a carb tuned. I fully rebuilt an edelbrock q-jet and tried running that with no luck. Then I slapped on my edelbrock performer carb (with the adapter plate) with no luck or change of symptoms. Somebody correct me if I'm wrong, but if the idle mixture screws are bottomed out, the engine should die...correct.

The problem I have with both carbs is the idle is high (when the engine is fully warmed up) around 1700 rpms and no matter what I do to the mixture screws it stays the same or maybe even goes up a little more when I open up the mixture screws...the idle speed screw for the throttle is backed off completely. I found a broken aneroid cover in the q-jet (must have chipped it a little when I put the carb back together) so I'm thinking that may be part of the problem with the q-jet. I'm going to put it on the shelf until I can get a new part. The performer carb sat for a while so I'm thinking that could use an overhaul...so I bought a rebuild kit for it and hope to have that done in a couple days or so.

Carb issues aside, would my problem also be a good indication of a major vacuum leak somewhere? I have an edelbrock performer rpm intake I'm going to install to eliminate any possible leaks around the squarebore to spreadbore adapter plate. I also have all vacuum ports blocked/capped off on the carb/intake too...even the brake booster. Is there anything else I'm missing? Any help will be greatly appreciated.

Thanks!

 

Sounds like the high idle is hanging up. That it is happening on two different carbs indicates the electric chokes aren't getting proper voltage.

If the throttle blades are open enough, the engine will continue to run with the idle mixture screws turned in all the way. Being held open by the high idle cam would be sufficient.

 

If my egr block off plate was leaking, could that cause my problem?

 

It would cause problems, but not what you're describing.

 

I got it fixed...you pretty much nailed it. I double checked voltage going to the choke and it was good...a little over 12volts. I put the q jet back on and readjusted the choke and I got it working. I had it too tight so it wouldn't open all the way. I still think the fast idle cam might be a little bound up, but will have to wait for it to cool off. Thanks.