93 LeSabre no spark

[brian_k24]

I am working on friends car. It is 93 LeSabre 3.8 about 195,000 miles. She started it the other day and drove about 100 feet and then it died. Car cranks fine but no fire.

I checked fuel pump relay and felt like it worked, then checked fuel tank and could hear and feel pump running. Checked for spark and it had none, checked all three coil packs and none have spark. Went through and checked all electrical connections, removed and reset all relays and fuses and still no spark. Tried to pull codes by jumping the A and B terminals, just keeps flashing 12 which was suprising because the SES light has been on the last year or two.

Not sure where to look next, I was think the computer is bad but don't want to throw parts at it.

Need help,
Thanks

[richtazz]

I would bet it's a crank position sensor.

[brian_k24]

I thought about that too after I posted when I realized I probably erased the codes when I was checking the connections.

[Mickey#1]

Ignition control module & crank sensor are the top suspects. Did you check the fuses under the dash on the passenger side? Sometimes the oil pressure sender shorts out & blows a fuse there. That fuse (#6?) also supplies power to the ICM.

[brian_k24]

I have checked all the fuses and they are good. I replaced the crackshaft postion sensor still no spark but now have codes. The codes are 16, 17, 18, and 42.

[richtazz]

code definitions as follows:

16- Charging system voltage was either below 9 volts or above 17 volts for 10 seconds
17 PCM did not detect any spark reference pulses within 240 fuel control reference pulses (80 crank revolutions) while engine was running below 1200 RPM.
18 Cam/Crank Error
42 The EST signal did not change when the ECM applied bypass voltage to the ignition module.

17, 18, 42 all point to a bad crank position sensor. The code 16 suggests a slipping belt, bad alternator or other charging system anomaly.

[brian_k24]

I have replaced the crankshaft position sensor and still get the same results. Is there anyway for me to test the sensor to see if the new one is bad?

[HotZ28]

If you have a tachometer or scanner, check for engine rpm while trying to start. No rpm would indicate, no CPS signal. In addition, you should remove the ignition control module and take it to AutoZone for testing.

[brian_k24]

I brought the ignition control module and coils into Autozone last night and everything tested ok. I don't have access to a scan tool so I guess will have to bring it in to a shop.

Thanks for all the help.

[HotZ28]

Tried to pull codes by jumping the A and B terminals, just keeps flashing 12 which was suprising because the SES light has been on the last year or two.

It may be time to replace the ECM/PCM.

[brian_k24]

Well for $20 at the local salvage yard I bought an ECM. Cleared the codes installed the ECM and still no spark, now have just code 42.

[richtazz]

When you changed the ECM, did you swap the prom chip from your old one to the new one? The same ECM number can have several different prom chips in it for different engine combinations. If you didn't swap the proms, that could be your new problem. The code 42 is still pointing toward the EST circuit (Electronic Spark Timing) which involves the crank and cam position sensors, the ignition module and the ECM.

[brian_k24]

Yes, I did swap the PROM. The only part the EST circuit I haven't tested or replaced is the cam sensor.

[HotZ28]

Originally Posted by brian_k24

Yes, I did swap the PROM. The only part the EST circuit I haven't tested or replaced is the cam sensor.

The cam sensor has nothing to do with spark! You must have a "failure to communicate" from the CKPS to the ICM, or the ICM to the PCM. Did you check for 12v input to the ICM? IIRC, there is a fuse on the firewall fuse/relay panel for this.

[brian_k24]

Well just spent all day looking for a bad connection or broken wire and no luck . I have 12 volts on the red wire w/black strip at the ICM. I checked continuity from the CKPS plug to the ICM plug and every thing was good. Checked continuity from ICM plug to the 8 conductor plug above the rear rocker cover and was good there also. Opened up all the wiring harnesses that come from the fuse/relay center and from firewall to the engine for a visual inspection all looks ok. Just to make extra sure took the CKPS and ICM and put in my Olds and it runs fine. Wow, don't remember ever being so stumped