Combustion problems with a 1986 Chevy 350/5.7 engine
It's in a 1986 Chevy G20 Van, V8, Calif. It's a 3/4 ton, the VIN says it is, or was, a 5.0 liter V8 4BBL LF3. It had a 350/5.7 factory engine installed by a local dealer in 1998. There's about 125,000 miles on that engine.
I've had this van for about six years. I've never driven it much, it always started, but it needed an alternator. I recently put in a new battery/alternator and rewired the starter. After that it had acceleration and combustion problems. It runs and sounds great at idle, but under load, at low speeds, it hesitates, sputters, stalls and occasionally backfires. Some of the symptoms indicate a possible problem with the computer controlled units on the carburetor, the Mixture Control Solenoid or the Throttle Position Sensor. I started looking through the wiring and fuses and found out how to read the ECM/MIL flashes on the Check Engine Light. The first time I checked, there was trouble code 34 - indicating a problem with the MAP sensor - but, since then, no other codes have showed up. Now I'm looking into the 22 pin and 18 pin connectors on the computer module, tracing wires, testing and looking for trouble. I have a volt/ohm meter, a cheap tach, and a good hand held vacuum pump.
The truck has a rebuilt, Rochester Quadrajet E4ME - 17085524 - carburetor.
The ECM is labeled, re-manufactured, 01226865.
The PROM chip is marked, DELCO CE1090N 8520.
What I need is Help in locating and identifying all those sensors, vacuum switches, valves, relays, and threaded plugs, screwed into the engine in various locations. I could use Links to web sites with information on how to do step-by-step testing procedures for troubleshooting and diagnosing the problem.
Tips from your personal experience, clips from your private archives or just plain sympathy will be welcome.