'92 Lumina 3.1L - runs too rich (?) after 10 minutes off

Leaking fuel injector(s) is my guess.

'Leaking' ? Wouldn't that be a constant problem ?

To me, it's gotta be some damn sensor, but there's a number of them .... any insight appreciated.

thx

Sounds like a fuel pressure regulator with a leaking diaphragm to me. Bob

I think it's a bad cold start sensor. When the engine is cold it is used to enrich the system so cold starts are easy. When system is at or near temp. the sensor should not provide this function. The description seems to indicate that this sensor is on its way out. I think GM calls it CTS looks like a small spark plug somewhere around $15 or so. Also if possible scan for codes. In 92 they still had ALDL and all you need to do is to short out an A and B terminal on the diagnostic port. Look it up in a manual.

Speaking of manuals, you really should get one yourself and understand what you are talking about before you start giving advice. Generally wrong advice is much worse than no advice at all. The coolant temp sensor works nothing like you describe. A flakey sensor will usually cause warm driveability problems as well. A failed sensor will turn on a check engine light. I've replaced a bunch of fuel regulators and he describes the typical symptoms to a tee. Bob

Thx dudes. I can and have jumped the diag port on the vehicle (though not for this particular problem), and I have a Chilton-like manual with pages of diag codes, so I will try that out. I didn't try that yet because, inform me if I'm wrong, that unless the Check Engine light is on, the diagnostic info won't show or will be inaccurate.

Since it wasn't a pressing problem, I've been just dealing with it, and before I got out there and started mucking around, I figured I'd see what others' opinions were. And I highly suspected the fuel pressure regulator, but wanted to hear otherwise due to the cost. :-( A trip to the boneyard is in order, I guess.

thx again

You are wrong. Codes may be stored w/o a MIL. In fact, a code check is a necessary check for the overall diagnostic system (i.e., if the MIL does not flash ANY codes or does not operate that problem needs to be corrected first).

I had that happen on my '90 Cutlass (3.1L) and the gas leaked into the intake air tube (due to a vacuum tube which sucked the gas into the intake tube), it was rather obvious (gas smell and gas leaking from the intake tube). And yes, it had that "rich" running feel. HTH, -PapaRick

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Bob wrote: