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Cavalier: won't start when engine hot

'99 Cavalier, 2.2L. On warm days, with a hot engine, it won't start. After sitting a couple of hours, it's OK. When it won't start, the temp gauge is stuck on cold. As soon as this starts working, the engine starts. So, maybe a bad ECT.

But, after starting, the temp guage will intermittently fail again; and, when it does, the oil, battery, and coolant alarm lights all come on. These go on and off together with the temp guage failure. (The engine keeps running.) I suspect these are also failed when the car won't start, but the lights are just on anyway, so you can't tell.

The car has had wiring problems before, but I don't see where these sensors have anything in common, other than the computer (PCM). But, the engine does keep running, so it can't be totally crapped out. I hate to have to spring for a new PCM, just to find out whether that's bad.

Any thoughts/experience would be appreciated.

Thanks, George

Reply to
George
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Bad ground someplace...

Reply to
Noozer

hi therei vote for either ignition module, or for temp sender for the ECM, or possibly the crank sensor

all of which commonly fail and can/do cause this symptom

will have to rule each one out independantly

the module can be tested at almost any parts store for free

the sensors are cheap and i would replace the crank one regardless they are very common to fail

good luck

Reply to
easterwabbit

I don't really like to think that - too much work. Aside from that, though, the oil & coolant level sensors are switched to ground in the fault state. So, a bad ground on the sensors couldn't cause a fault ... which pushes the problem back toward the PCM. Meanwhile, the open-circuit ECT voltage from the PCM reads OK (5v) when the temp gauge is failed. And, for that matter, the engine does run in the 'fault' state - it just won't start.

But, you may well be right. Before I start looking, I'm going to hope really hard that someone else has a magic bullet.

Thanks, G

Reply to
George

Well, it was a somewhat broken wire, down near the PCM. Or so it seems

- it wasn't as hot today as yesterday.

G

Reply to
George

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