'89 Cutlass Supreme International shuts off, now won't start... (Page 1/3)
Quad Raider AUG 15, 08:57 PM
This is my daughter's car. 2.8L engine. The trouble started about a week ago when she said it got hot in traffic. It didn't overheat. I checked it later that day and neither radiator fan would come on. I unplugged the engine coolant temperature sensor and both fans came on. I replaced the ECT sensor with a spare but the fans still don't come on.

Since then, the car has started dying while driving. Last night it would crank but not start, until I pushed the gas pedal to the floor and even then it ran really rough for about 20 seconds then evened out and ran fine as I drove for a few miles. My plan was to have my daughter swing by a parts store to get the codes read but my daughter couldn't get it started.

The car has been in the family for a decade and had an engine rebuild 2 years ago. It's never had any of the sensors replaced. Ordinarily I'd suspect the crank position sensor was going bad, or maybe the ICM, but that wouldn't expaln the fan problem, would it?

[This message has been edited by Quad Raider (edited 08-15-2012).]

Tstang429 AUG 16, 01:42 AM
ecm itself? We had an 85 cavalier that the fans wouldnt come on did all sorts of test and all wiring and sensors where fine just was no longer getting a signal from the computer we just ran a switch. Maybe yours has a similar issue and the ecm failed.
Quad Raider AUG 16, 09:15 AM
Yeah, I was thinking a bad ECM might be to blame. The car has 235,000 miles on it.
jaskispyder AUG 17, 10:34 AM
can't you just check the codes like on the Fiero?
Quad Raider AUG 17, 01:34 PM
I think I can. I'll try that tonight. I've found all kinds of theories on the internet about what the problem could be, from clogged fuel injectors to a dying fuel pump.
Quad Raider AUG 19, 01:33 PM
OK, I got all kinds of codes. They include:

O2 sensor
ECT sensor
MAP sensor

But nothing about the ECM or the fuel pump. I also noticed that the positive battery cable end at the battery had some corrosion on it. The O2 sensor may be factory original, so I think I'll start there first.
E.Furgal AUG 19, 04:03 PM
k.i.s.s.
start by testing the FAN RELAY.. and fuse..
my bet is on fan relay..
start car (if you can) and put a/c on.. that would kick fans on, bypassing the sendor, but not the relay,, no fans, relay or wiring, fuse..
Quad Raider AUG 20, 01:03 PM
I think the fans and the relay are good, because the fans came on when I unplugged the ECT sensor. I will replace the crank position sensor this weekend. I also need to replace the positive battery cable.
Quad Raider SEP 07, 09:36 AM
Haven't had much time to work on it. I replaced the crank position sensor and it didn't make any difference. I also had the ICM checked and the parts store said it was good. Don't know that I believe it. My plan is to replace the ECT sensor with a new one this weekend.
Racing_Master SEP 10, 06:23 PM
MAP is a big thing, will make it run like crap. ECT is probably thrown because you unplugged it. remove the negative battery cable for 30 seconds - 1 minute, then put them back on. Try to run the car, then get codes again.

A Faulty MAP could possibly cause loads of issues, including no performance.

Does it fire up when cold, and die when hot? in 89 GM had some problems with the Multec fuel injectors. Ohm them out if you can, should be around 16 ohms. Have a 'Vette in the shop right now that has a fuel injector problem (Multecs) and it causes the ECM to stop running the injector drivers. No codes in that situation.