Ok first off I love my Q-jet. always has and always will be my choice of fuel induction. Now heres the problem.

Motor runs OK cold, and runs worse as it gets hotter. Misses and generally sounds as if there is no timing. When driving it and you hit the pedal to go it has almost a lugging feeling unless the secondaries open then it sounds like it shuts off, and then wakes back up and runs all the way out to what ever you let it, but has no power while doing it.

Now I've tested every sensor on the car but have not found one to be operating outside normal parameters, I did spark plug wires, cap, coil, module, 02 sensor, and tuned the carb 500 different ways. Still no improvements.

It was running great until I turned it off, then when i restarted it, it ran like crap, thought it was wires so i changed them and installed a blower, still has the same issue as before the blower, then i did the above listed items to no solution. I am looking for ideas, i am at wits end with this car, have tried every trick in the book twice with no luck. Any suggestions would help. BTW the carb works fine.

Heres what is done to the car, I have the ZZ4 chip and comp, MSD ignitions, 67 Camaro Steel heads ported and large valves, a blower cam 268-276 duration with about .5 of lift. 1.6 ratio roller rockers, camden blower, new 760 cfm modified CC carb, police package fuel pump, and the motor is a 355 cid, just freshened a few months ago.

 

2 things i find make tuning the CC Qjet a breeze is a digital voltmeter and a dwell meter.

Have you tuned the carbs MCS using a dwell meter?

Have you checked the 02 sensors voltage at idle, cruise, and WOT?

Have you adjusted the secondary air valves tension?

if you are using headers, you really got to heat up the exhaust gases to get the dwell moving (i know i have to anyhow). using a heated 02 sensor would fix this.

Hopefully its something as easy as tuning with a dwell meter and secondary rods and hangers, the voltmeter will let you know if the secondaries are rich or lean. sounds lean to me.

you may want to try the carb boards too, probably get more repsonses

 

I did exactly what you are describing. I figured out how to get it running, well enough to drive but i still suspect there is something else hidden that is not showing up. Here the screw ball part. If I run the idle mixture screws retardedly rich and the idle air bleed valve near to all the way in, it runs well for a while but eventually craps out all over again. Unfortunately my daily driver had some major issues so i had to miss work today so I gave up on the hunt and brought it to a gentle man by my house who runs these cars in the 10's with the factory Q-jet. So I turned him loose on both cars. The GTP I said make it stop overheating (it's undr warrenty so GM eats that bill and the Camaro and told him go to town. I'll post what he comes up with when i get it back. What kills me is not the cash i lose by taking it to a someone else, instead it's admitting defeat that kills me.