1992 Grand Prix Ignition Probs

[pPhunk]

So I'm trying to get a friend's '92 Grand Prix (3.1L) to start... After she's let it sit for 6 months.

There's no spark from the coils, and no trigger to the coils from the ignition module. There IS power to the ignition module, and the CKP is presenting about .5V AC at the module (which I THOUGHT was proper). So I replaced the module. No luck. Plugs and wires test to proper resistances, coils test fine, there is simply no trigger signal from the module to the coils.

My questions are these:

-What should the CKP actually put out to the IGN Module? This is the early style (2 wire, magnetic pulse) CKP, and I don't have any actual specs to compare to, although I thought that .5V AC was a fair rule of thumb for a magnetic pulse sensor.

-With the CKP (potentially) eliminated, as well as the coils, plugs, wires, and IGN Module, is a new PCM the next step? Has anybody else dealt with a problem like this?

Now, I'm an ASE cert. mechanic so I'm not groping in the dark here, but BMWs are my specialty, and I just don't have access to any proper material on the Pontiac (beyond Haynes). So I need to ask you experts on the forum. I really appreciate any help.

Thanks,
Patrick
[email protected]

[richtazz]

The ecm is under the hood on that car, so there is a good chance that it could have a wire chewed by mice or a corroded harness.

[pPhunk]

Originally Posted by richtazz

The ecm is under the hood on that car, so there is a good chance that it could have a wire chewed by mice or a corroded harness.

Yeah, I've checked the harness and it's in fine shape. I pulled and opened up the ECM to look for anything obvious (blown power supply capacitors, burnt resistors, etc.), but there was nothing obviously amiss. There was no evidence that that the seals were leaky or anything.

Since I'm basically down to either the ECM or the CKP, I'm hoping that my test specs on the CKP were incorrect. If it's not too spendy maybe I'll just replace it and see. In the meantime, does anybody know the exact testing specs for a CKP in that car?

Thanks,
Patrick

[richtazz]

Crank sensors are a common problem on these cars. Just beware, the o-ring seal can get stuck in the block and cause you all sorts of nightmares getting the old one out. PATIENCE PATIENCE PATIENCE

[pPhunk]

Originally Posted by richtazz

Crank sensors are a common problem on these cars. Just beware, the o-ring seal can get stuck in the block and cause you all sorts of nightmares getting the old one out. PATIENCE PATIENCE PATIENCE

Any hints for removing the old CKP? It seems like a royal bitch to reach up between the oil and tranny pans to reach it. Can I rock the engine forward to get to it from the top, or anything like that?

[y2kpa2]

You can get it that way (From The Top) But you will have to move the engine foward and remove the altenator. you can not see it you have to feel what you are doing. there is a bolt holding it down i think it is 7/32 and it is not easy to get to with a ratchet, so be ready to get creative with flex extentions and U-joints, once it is unbolted spin it around several times before pulling on it to loosen it. most of the exposed plastic WILL break off so just break off where the connector plugs in at and bend the metal connections straight from there 90 deg position get a small set of vice grips lock on the CKP connector pins you just bent straight out rotate and pull until (Hopefully) it comes out in one piece. (Yeah its easer said than done) Good Luck!!