I have a '91 L98 w/ 84k that I recently changed the ignition module, cap, rotor, wires, plugs, with no engine codes and the thing is still running very rich.. can smell it. It has also recently stalled a few times on me and I cannot start it until I let it sit for a few minutes, almost like it's flooded. The idle also fluctuates frequently between
Eric
You may have a sensor telling the computer that the engine is running cold and it is in effect choking it (adding more fuel). If that is so it will eventually shut you down by flooding it out. How's your fuel mileage? My guess it that it sucks, (in a bad way ;-)).
Good to see you back, Dad. It was too 'f'ing quiet in here without you...
TomC '90ZR1
Fuel mileage is not as good for sure, but nothing horrible. If a sensor was bad, wouldn't the computer put out a code... there's nothing in the computer that says anything is wrong. Any other suggestions? I do get some popping in the exhaust occasionally when down-shifting as well.
Eric
No more suggestions, but I just went through this same scenario with my sons
91 and we changed all of the stuff you did and more before we thought it was fixed. Ran good when I left and while it was a cold engine. Right after we "fixed it" it left him setting in the bank drive up window on Friday afternoon. Had it scanned and it showed a faulty temperature sensor. Changed it and it now runs like a charm. Is that your problem, don't know, discount it if you want it never threw a code.Dad is right , check the water temperature sensore first. And check your fuel pressure regulator. A ruptured diaphragm could cause the problem. RPM fluctuation could indicate an intake leak.
To Dad and tom_I_35806, What would the water temperature sensor have to do with anything? Mine works fine as far as I know it, temperature seems accurate. As far as the intake, you're referring to the intake manifold I suppose. How would I diagnose that? The idle fluctuation gets worse if I throw the AC on... don't think the AC has anything to do with it, just think that the AC exaggerates whatever problem it is. Thanks again.
Eric
Sensor can give a erroneous bit of information to the computer and therefore sends an incorrect request for more fuel. The sending unit for your coolant temperature gage may not be the same as the one used to control your fuel. Do you have more than one temperature sensor and did you have a scan tool check it? It don't have to set a code that would appear in your DIC to be a faulty sensor. Sorry, I can't look it up, I no longer have a manual for my '92 which may be different anyway with the LT1 and its reverse flow coolant.
Dad
A bad O2 sensor can also make the engine rich.
Al
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