Delta 88 (1988)

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I have a 1988 Oldsmobile Delta 88 with a 3.8 V6 FI that has 88,000 miles. I bought this car for my son in Oct 2004 and as the weather grew colder the car now takes about 20 minutes to warm to the point you can drive it. About two weeks ago my son was warming up the car when he noticed the Catalytic converter was glowing red. I've replaced the Cat but it doesn't affect the way the car behaves and in fact became slightly worse, in that it now backfires at idle. So I first tried to read the codes but the reader just didn't register anything, they may have rented me the wrong unit and that's why it didn't read. Next thing I did was check for loose or grounded spark plug wires, I then unplugged each plug wire one at a time, observed a noticeable dip in engine speed for each cylinder, confirming that I have detonation all cylinders. I performed vacuum test at varies points and found 15-17 PSI at all test points, I also found a couple of broken lines and repaired them, but this did not improve overall vacuum PSI. So then I went out and picked up a Fuel Vacuum tester and a fuel filter. The instructions for replacing filter said to relieve the pressure in the fuel system which required that I disconnect the fuel pump relay and open the gas cap. I did this and started the engine, the car ran rough but didn't run out of gas instead it kept on running (must not have unplugged the correct relay). After running about 20 minutes it began to backfire a little worse and gag, so I figured she was about to run out of gas. Instead the engine idle went up and it begin to run smooth. I shut the engine off and restarted it, the idle dropped to normal and when I test drove it, it ran great. I decided to change the fuel filter anyway and return the tester unused, assuming I don't need it just now. I allowed the engine to cool down while I changed the fuel filter, then repeated the 20 min warm-up test. Engine started rough, ran for about 20 min, began to stutter and backfire, idle speed went up then engine begins runs fine. So yesterday I replaced the water temp sender and repeated the 20 min warm-up test. Same results. I have also noticed a great deal of moisture leaking out of tailpipe during warm-up as well a great deal of white colored exhaust. MAP sensor appears to be functioning properly.

My assumption at this point is this:
Timing Chain O.K.,
Temp sender O.K.
Injectors O.K. but what do I know?
Fuel Pump O.K. but not ruled out
Idle Control Valve Possible Cause
Throttle Control Sensor Possible Cause
Oxygen Sensor Interested (Engine will shut down if I unplug it)

posted by  smitti

the cat was glowing red because the mixture was far too rich.take out the spark plugs when the engine is cold to see if there is something amok.
steam in the exhaust could mean a head gasket problem...are you loosing coolant? do a compression test,and then check all the emissions related stuff.when you say maf sensor is working,who checked it?

posted by  the lobster

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