I have an 1990 Oldsmobile 88 with a 3.8L V6. It has been running fine up until a few weeks ago. When I was out doing errands and after coming out the store, (the car had been off for 5-10 minutes), the car would turn over but not start. A friend towed me home. All my friends said it was probably the fuel pump and to replace it.
Next day I jacked the car up, blocked it, dropped the fuel tank, drained the tank (fuel was clean) and replaced the pump. Put everything back together and it has run without problems for the past 10-12 days. I have probably used two tanks of gas. Saturday morning went out to start the car, turns over, but will not fire, (there is a little less than half a tank of gas). It is acts just like it did before I replaced the fuel pump.
If I pour a tiny amount of gas (about ½ shot glass) down the air intake, turn it over, it fires and/or runs for a couple of seconds then dies.
When I turn the key on the fuel pump does not come on. Removed the fuel pump relay and jumped the #30 and #87 connection, turn the key on, fuel pump runs but car will not start. I also broke the fuel line to make sure the fuel pump was actually pumping fuel, it was.
Checked the contacts for the fuel relay at the relay center. When key is on #86 is the ground; #87 is positive and always has ±9.5 volts. I cannot get any readings from #85 when the key is on, and/or when actually trying to start the car.
Went to check the fault codes and discovered the check engine soon light does not work. Also when I turn the key on the fasten belt light always come on. The other lights: amp, oil, brake, and temp, (have basic instrument panel); may or may not come on. Turn the key on some lights may come on right away, others may or may not come on after 1 or 2 seconds. Try to start the car some lights may stay on, others go out. Stop trying to start the car but leave the key on, some lights that had been on may come back on, either right away or in a few seconds, and/or lights that had never been on before trying to start the car come on either right away or in a few seconds.
When I turn the key off and start the process all over I get different a combination of lights. The only thing constant is the check engine soon light never comes on and the fasten belt light always come on. Also when I turn the key on I always hear a click in the engine compartment. The starter turns the engine over just like it always has.
I have had this car for 7-8 years. About six years ago I had to replace the ECM. I can not remember exactly what the problem was but it was along the lines of not starting, hard starting, rough running, etc. What ever it was, replacing the ECM solved it and I have not had a problem with the car until now.
I understand heat (±100 deg.) Really screws up the ECM. I live in Florida and the car is kept out in the open, no shade. I have been out work for 4 years and flat broke. I can't afford to take the car to a mechanic or purchase a lot of parts or test equipment.
I am thinking the ECM is bad, but I do not know of a simple test to confirm it. I hoping someone with real knowledge could tell me how to test it or base on the above formation knows the ECM is shot. I have not worked on a car since my college days over 40 years ago.