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Roy Belding
Roy Belding, ASE Certified Technician
Category: Pontiac
Satisfied Customers: 6177
Experience:  Master ASE since 1980
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1999 grand prix gt, won't start. No spark to plugs but icm

Customer Question

1999 grand prix gt, won't start. No spark to plugs but icm was just tested and is fine. Car ran 4 hours ago. We changed the head gasket now it won't start.
JA: Is this your first time dealing with this issue? What size is your engine?
Customer: Yes. 3.8L 3800
JA: Are you fixing your Grand Prix yourself? What have you tried so far?
Customer: Yes. Checked for spark at plugs. No spark, used test light have power at icm.
JA: Anything else you want the mechanic to know before I connect you?
Customer: Had a head gasket leak, car ran fine before, pulled into garage, changed head gasket, now it has no spark.
Submitted: 1 month ago.
Category: Pontiac
Expert:  Roy Belding replied 1 month ago.

hello, my name is ***** ***** I will be glad to assist you. please allow me a couple of minutes to gather some basic info.

Roy

Expert:  Roy Belding replied 1 month ago.

when you crank the engine does the tach move up a little bit???

do you have a scan tool to read cranking rpm???

checking the crank sensor signal.

did you make sure the cam sensor connector is tight and clean???

Roy

Expert:  Roy Belding replied 1 month ago.

are you there

Customer: replied 1 month ago.

When I turn the key to on it goes from below 0 to 0 but when I crank it doesn't move at all. No tool to check cranking rpm, what do I need to do to check the crank sensor signal it is plugged in tight but I didn't check if it was clean as we didn't unplug it during the head gasket set change

Expert:  Roy Belding replied 1 month ago.

you need a scan tool to see if the pcm is getting a crank signal from the sensor. if it does not get a signal there will be no spark.

inspect the harness for any damage. it goes to the icm as you had it off for the job. check the cam sensor as well. it is on the timing cover.

Roy

Customer: replied 1 month ago.

Would the icm still pass testing with a multimeter if the crank sensor was bad? We did test the ICM and it passed the test.

Expert:  Roy Belding replied 1 month ago.

icm test with voltmeter??? that only means it has power into it. it does not verify it is working.

you can remove it and take it to a parts store and they can test it to be sure it is working. that is a free service.

Roy

Expert:  Roy Belding replied 1 month ago.

any update???

Customer: replied 1 month ago.

Having the ICM tested right now. Crank sensor is clean and connected well.

Expert:  Roy Belding replied 1 month ago.

ok