Rob C

Hello,
I am reading all I can about getting the Q-jet to run right on my 86 TA LG4, and I am really tempted to just eliminate the computer. It runs really bad sometimes and I have been trying my best to troubleshoot it, but by the time I buy all these meters and things, I could buy a new carb and distributor. Right now, I have checked the choke and secondary operation, and replaced the EGR valve and plugs, cap and rotor, and O2 sensor. I get poor mileage and it bogs and hesitates at anything over half throttle. Timing and spark are good, is there anyplace good to get the carb rebuilt without sending it out for weeks? I heard Jet is good, any experiences? Also, the belt has been off of my AIR pump since I bought the car a few months ago, what effect will this have? I notice a very loud pop coming from the cat sometimes when I shut it off, but the spark plugs seem to tell me the engine is running about right, maybe a little lean. I just want to know what I should do to get the car running right and stay legal. I can be much more detailed if someone thinks they can help. Thanks in advance.

Biochem

Read the article by Ed Maher on this site. It sounds like your secondaries are opening too quickly or something.

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1984 z28 w/ a 357 cu in. monster engine which is looking like the posterchild for Edelbrock with the exception of the Holley 750vac... all the suspension stuff... 9-bolt posi disk is in...

-=ICON Motorsports=-

Damon

Rob, the only real tool you need is a begged/borrowed/stolen Diacom or other diagnostic tool. You can't diagnose crap on a computer controlled car without one. You'll spend weeks and hundreds of dollars throwing parts at it and maybe still not get at the real problem.

You'll be AMAZED how much you can learn spending 15 minutes with a Diacom hooked up.

Rob C

Thanks for the advice guys. I didn't know the Diacom would work on a carbed car. I remember people using them for TPI.

jrr

I have cured my 1985 LG4 and Guinea Pig Olds 88 of many of the same computer problems by ripping that CCC junk out and re-engineering everything to early 1970's specs!

One of my biggest problems actually came from a bad fuel pump. Bad sensors nickel and dimed me to death, too. The TPS was a usual suspect but I had fast idle problems from a bad EFE (Early Fuel Evap) switch. EFE controls the exhaust manifold flap that forces hot gases under the intake to warm it up. Even when everything was working, I could still tell that the computer was interfering with engine and hampering performance. Finally, I had enough!

In both cases, I acquired older model Q-Jets and HEI distributors and retrofitted them in place of the CCC stuff. A little vacuum hose rerouting for the vacuum advance, cannister, exhaust heat and warm air intake control restored those devices. My smog pump now pumps full time to the cat converter. This anti-technology approach has given me two cars that have the best throttle response and no telltale smell of a desmogged engine. ALL that computer crap is gone and the engine compartment is much cleaner now.