What are the classic symptoms of a bad ICM?

My car cranks over fine. Battery is good 12.5v and I use a booster cable when it gets low. I can crank the car for 30 minutes cumulative, stopping every15 seconds and waiting about a minute for the starter motor to cool.

Then, it will catch and run very well like normal. I let it run to charge the battery and even drive the car.

But as soon as I turn off the IGN, it cranks over but doesn't start.

Fuel PSI is - 42 psi. I can also hear the fuel pump prime.

So, it must be ignition. If it was an OPTI, then it would be consistently bad. But in this case, it is a hard crank but when it does catch, it runs very well / smooth.

 

You troubleshoot the opti??

Try:
http://shbox.com/1/4th_gen_tech2.html#opti_test

That should get you pointed in the right direction. And try to hit him up with a paypal donation.

He's saved alot of people alot of money by helpin em diagnose issues by themselves.

Good luck and keep at it,
Ivan

 

Thanks. When testing the A and D terminals for 10v, the red lead goes to those terminals. Where does the black lead go to? Directly to Battery or is there a circuit ground?

 

It's a ground. You could use the black or (-) on the battery for your ground.

Test the Terminal A with the red and then put the black on a good ground. Should read 10-12 vdc

Then test the Terminal D with red and use the black to ground out. Should have same reading.

Next, take the red probe and touch it to the battery's + terminal. Black to the C terminal and it should give you that exact same reading. You are testing the ground now for the ICM.

LUK,
Ivan

 

Ok, I just checked and I had 12.4v I turned the ignition off and reconnected the ICM.

Just for kicks, I cranked it and it fired up.

So, it has power and the fuse & coil seem to be ok.

It was raining here which doesn't happen much in So Cal. I'm wondering if moisture got into the opti? It is a '95 so it is vented.

Is there a check valve or something I could check the venting operation? This is only a guess since the symptom cleared up when it stopped raining.

 

No check valve. The do get wet but usually not unless your doing some heavy duty boggin......

If you do get the chance take the ICM off and get it tested. When you do get it tested, ask them to do it several times to simulate real world conditions and get it warmed up.

That's usually when it starts to fail if it does.

Good luck to you and take care,
Ivan

 

When I take off the ICM, who can test it? Can the dealer run it on their equipment or do I take it to Pep Boys (aftermarket)?

 

I took mine to AZ....call around though because the first AZ didn't have the wiring harness for my year...go figure.

They can test it. I don't know if the dealer would or can...they are more like...yeah, buy it!

Keep us posted,
Ivan