ECM Computer testing?

Question

I have a 1990 Oldsmobile Cutlass Supreme that has no spark and thus will not start. I have checked the car over and have been told that the ECM is bad. I completed a check on the vehicle and recived a 12-12-12 code which tells me that the computer is working. Anyone know where I can take this computer OFF Vehicle and have it tested?

Answer 1

coil pack is bad - - - - - 95% sure.

Answer 2

You're on the wrong track, I think. The PCM does not have anything to do with creating the ignition spark, just the timing of it. The flashing code 12 three times with nothing else means that the PCM is likely good. No guarantees though as lots of these were bad. To fix spark though, it is NOT the PCM. What you have to do is take the connectors off at the distributor module at the right side, the 2 pin connector first. This is just a power and ground supply to the module. Turn ignition on and there should be power and ground at this connection. If there is one or neither, chase back and repair. This is usually not the problem but needs to be checked. Locate and remove the 3 pin connector at the top left of the module and test the resistance from A to C. Should be around 900-1000 ohms. If it's close, that is probably okay as well. This is the crank sensor and circuit. If it is open, you either have a open sensor or wiring to it. Both of these happen, so check. If all that is good, you can be pretty sure the ignition module has had it. The other connector is for the timing thing I spoke of and should not affect spark. Make sure you test as these parts are not cheap.

Answer 3

ECM's going bad are very rare and most likely when someone tells you it's bad, then it's usually a cop out diag job. I would check the ignition system. If there's no spark in any cylinders, check the coil. Check visually for cracks, loose wires or corrosion on the connections of the primary side(not the side w/the plugs and wires). If nothing, then use a multimeter and check for resistance between companion cylinders and compare to one another, they should be within a couple hundred ohms.

Answer 4

OMG! It's happening to someone else...I'm so sorry. I had a nightmare story from hell that started just like that. Fortunately, it is recoverable. I'll spare you all the creepy details and steer you in the direction of 1)an intermittent problem with the in-tank fuel pump/filter (you can hear when it's not working) 2)the hall effect switch in the distributor 3)don't forget the knock sensor, common failure The ECM is almost never JUST BAD, unless you have some reason to suspect that it may have been compromised.

Answer 5

Some very good answers here, but one has been overlooked, you may also have a faulty crankshaft position sensor. This is located on the front of the engine and most service manuals have a testing info for this. If you are going to attempt to diagnose this yourself and don't have a book it would be a good investment.

Answer 6

check coil[s] first....