I have a 93 GP with the 3.1 V6 engine. Suddenly about a week ago it refused to start. No hint of it trying to start. Battery fairly new and it cranks fine. First thing I checked for was whether I had a spark - no spark. I did this by pulling the HT leads off one of the coils and cranking the engine - no spark. To double check I got one of the old spark strobe light gun used for spark timing check on the older vehicles. I cranked the engine with the sensor clamped around one of the HT wires - no flashing strobe. I tested the strobe seperately - it works.
I got the multimeter. I disconnected the power connector to the Ignition Control Module (ICM) - 12+ volts - so its getting power. I disconnected the connection from the Crankshaft Position sensor (CKP) at the ICM and the voltage was in spec - about 0.8V. Spec is 0.3V to 1.0V I read somewhere. Resistance was out of spec though - 970 Ohms (Spec 400 Ohms to 900 Ohms) - so maybe a problem there.
At this point I'm thinking the CKP could be weak or the ICM failed. Those are the two most likely candidates. I tried to remove the ICM to get it bench tested somewhere but found and removed only 2 of the 3 bolts holding on to the engine block. Could not find the 3rd. bolt. Getting access to the ICM is tough - removed one of the fans to make it better but still no 3rd bolt.
So far I've worked from the topside of the engine. I could jack the car up and slide underneath but it looks like the AC plumbing pipes are in the way from the underside. I really don't want to have to start disconnecting the AC system.
So I'm looking for any input at this time re the following issues:-
1) Based upon what I've found are there any other tests I could usefully do with a multimeter to more difinitively convict or clear the ICM of failure.
2) Any hints on how to actually remove the ICM - finding the 3rd bolt.
This is a 24 year old automobile but very clean and unmolested with only 60K miles on it.
Thanks in advance for any help - DRAINXGRP.
I got the multimeter. I disconnected the power connector to the Ignition Control Module (ICM) - 12+ volts - so its getting power. I disconnected the connection from the Crankshaft Position sensor (CKP) at the ICM and the voltage was in spec - about 0.8V. Spec is 0.3V to 1.0V I read somewhere. Resistance was out of spec though - 970 Ohms (Spec 400 Ohms to 900 Ohms) - so maybe a problem there.
At this point I'm thinking the CKP could be weak or the ICM failed. Those are the two most likely candidates. I tried to remove the ICM to get it bench tested somewhere but found and removed only 2 of the 3 bolts holding on to the engine block. Could not find the 3rd. bolt. Getting access to the ICM is tough - removed one of the fans to make it better but still no 3rd bolt.
So far I've worked from the topside of the engine. I could jack the car up and slide underneath but it looks like the AC plumbing pipes are in the way from the underside. I really don't want to have to start disconnecting the AC system.
So I'm looking for any input at this time re the following issues:-
1) Based upon what I've found are there any other tests I could usefully do with a multimeter to more difinitively convict or clear the ICM of failure.
2) Any hints on how to actually remove the ICM - finding the 3rd bolt.
This is a 24 year old automobile but very clean and unmolested with only 60K miles on it.
Thanks in advance for any help - DRAINXGRP.