97 Trans am no spark
03-13-2013, 07:43 PM
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97 Trans am no spark I'm working on a 97 Trans Am that more often than not won't start, and when it will, only runs for a few seconds to a minute max. When it dies, it just dies. No sputtering, just flat dies like it's been shut off.
It's got a new Opti, coil, ICM, plug wires, and plugs. All the components and wiring check out good up to the ICM, but I get stuck there because I have no idea how to check the ICM itself other than replacing it. Does anyone know how to check the module other than taking it to a parts store or just swapping it out? Maybe a signal it feeds to the coil? I have a DVOM and it's helped me narrow things down to this point. Google's turned up nothing other than people saying that Autozone can check it.
Only codes present are P0100, yet the wiring checks good and both MAFs I've tried seem fine on another car. The car previously had a 95 PCM but I've switched back to a 97 PCM. If I left any important details out, let me know. I don't know what is and isn't important, LT1s aren't quite in my area of expertise. Appreciate any help, this car is making me feel dumb.
It's got a new Opti, coil, ICM, plug wires, and plugs. All the components and wiring check out good up to the ICM, but I get stuck there because I have no idea how to check the ICM itself other than replacing it. Does anyone know how to check the module other than taking it to a parts store or just swapping it out? Maybe a signal it feeds to the coil? I have a DVOM and it's helped me narrow things down to this point. Google's turned up nothing other than people saying that Autozone can check it.
Only codes present are P0100, yet the wiring checks good and both MAFs I've tried seem fine on another car. The car previously had a 95 PCM but I've switched back to a 97 PCM. If I left any important details out, let me know. I don't know what is and isn't important, LT1s aren't quite in my area of expertise. Appreciate any help, this car is making me feel dumb.
03-13-2013, 09:07 PM
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True, I have not checked the fuel system at all. I forgot to mention that a timing light during cranking shows when there's no spark, which is why I've been focusing on the ignition.
03-14-2013, 04:19 PM
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I went ahead and checked the fuel pressure, 42psi KOEO. Car will not start at all since last night, using the old (technically new) ICM or the new ICM, old or new coil, and tried putting the 95 PCM back in as well. The P0100 is gone after I did literally nothing about it, and has been replaced with a P1351, but I'm not sure why. When cranking, I haven't seen any higher than 4.2v once I start cranking.. it almost immediately drops to within 2.2-3.5v after that and maintains that range until I let off the starter which has been up to but no longer than a minute.
Grounds are good, as are all the engine harness wiring for the Optispark and ICM. Still getting no spark.
I'd really like to know what to look for as far as testing the ICM itself. The old module "passed low RPM but failed high RPM" according to the local NAPA and the new one "passed" right before they sold it to me. What can I check for at the connector running to the coil other than 12v on pin A? Best I can tell is pin B, coming straight from the ICM, could be just a ground switched by the module.
Is the CKP a possibility? If that's the case, wouldn't it fire with the 95 PCM? I've been told that the 95 does not use the CKP, so I haven't put much thought into it since the issue started when it was running with that PCM.
Grounds are good, as are all the engine harness wiring for the Optispark and ICM. Still getting no spark.
I'd really like to know what to look for as far as testing the ICM itself. The old module "passed low RPM but failed high RPM" according to the local NAPA and the new one "passed" right before they sold it to me. What can I check for at the connector running to the coil other than 12v on pin A? Best I can tell is pin B, coming straight from the ICM, could be just a ground switched by the module.
Is the CKP a possibility? If that's the case, wouldn't it fire with the 95 PCM? I've been told that the 95 does not use the CKP, so I haven't put much thought into it since the issue started when it was running with that PCM.
