Persistant Ignition Problem

DarkShard

Registered User
Okay, here's the deal. One day I started my 90 SC up and started to drive down the street. It bucked hard a few times and then died. I tried restarting it and it seemed like it would almost turn over some times, but at others it felt like the engine was fighting the starter. I checked for fuel pressure and spark and had both.

Not wanting to waste time with redundant posts, I checked the forums for similar problems. I see that if you try to start it and the upshift light stays lit, then it's the crank sensor. So, I ordered one of those and replaced it along with the cam sensor. Still won't start.

I used a volt meter to check the wires going into the DIS module to make sure that both the cam and crank sensors were sending signals (voltage was changing as the engine was cranked).

Confused, I checked for spark again, and there now was none. Upshift arrow still stays lit when cranking.

Checked the engine codes and it gave me code 14 if I remember right (Profile Ignition Pickup, I'm sure of that). So many people have had success by replacing the crank sensor I was sure that was it, but obviously not for me. Anybody have any clue as to what I should check next (and how)?
 
You may try the dis module..... the crank sensor is wired to it and the it converts it into a digital rpm signal and sends it to the PCM.... Then the pcm sends a digital signal down the spout wire to adjust the timing.... so in theory the car would have spark with out the pcm connected to the ICM. When you car starts it uses base timing... this is all done in the ICM... when the car starts the PCM uses the spout wire to adjust timing. Check to see if the TACH is moving during cranking, if it is you have a RPM signal. Also if things get bad... go get a noid light at the part store and check to see if the injectors are firing. This will let you know if the pcm is getting a vaild RPM signal from the ICM.
OR
Just take a chance and put an ICM on it.... I'd say it will fix it..... but I don't have to buy it if it doesn't ;) The CMP sensor code could be a results of the no rpm signal.

Good luck let me know if any of this helps......
 
Crankbolt?

How would the crankbold being missing cause that problem?!?

I'm not doubting you or anything, I just want to know exactly what to check for.
 
The vanes for the crank sensor are on the pulley assembly and it can walk out enough to not give the crank sensor a timing cue.
This is what I experienced.
 
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