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2008 Buick Lacrosse--Cranks but No Start
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hawk42
Novice
Nov 9, 2020, 10:33 PM
Post #1 of 4
(4241 views)
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2008 Buick Lacrosse--Cranks but No Start
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Vehicle: 2008 Buick Lacrosse--3.8L--43,000
Vehicle belongs to my mother-in-law who purchased it new, garage kept and serviced exclusively by Buick dealership. Vehicle ran and performed flawlessly.
My wife was driving the vehicle when about 3/8 mile after start up the engine suddenly stopped. No stalling, no missing, just bam--dead engine. She coasted to shoulder and tried to restart it. It would crank but not start. I went to see if I could help. I tried to start vehicle but with no success. It would crank over rapidly but still not start. I checked to see if I could hear the fuel pump running. I could and it ran a few seconds as it should. I them checked for spark at the spark plugs. No spark. My first thought was that the Ignition Control Module had failed so I removed it and took to O'Reilly's for testing. On their equipment, it failed. I purchased a new "Standard" brand ICM and installed it. Still no spark.
Then I got to noticing things that seemed weird to me. First, it had a "Check Engine" light but I could not retrieve the code. My code reader would show it was connected to the CAN, display the battery voltage but give the message, "No DTCs or Freeze Frame Data stored in computer memory". My reader is just an advanced DIY unit but it has never failed to retrieve engine or ABS codes if the lights are present. Next, it had no tachometer signal. Although the engine was spinning rapidly, the tachometer needle remained at "0". Finally and most weird is starter after run. The starter will continue to spin the engine a full 3 seconds after the key switch has been turned back from "start to "run". Prior to this , it never had the after run but now it does it every time. I thought maybe it was the start or crank relay sticking so I swapped out with another identical relay but after run continues.
Could you please give me your thoughts and recommendations on this? Could I have an ECM issue? I realize that no tachometer signal can be caused by a faulty Crankshaft Position Sensor circuit but with these other two things, it makes one wonder.
Thank you in advance for your reply.
As an aside, I took my new ICM back to O'Reilly's for testing. It failed but so did two additional new ones of different brands. So much for their testing equipment. I have never had much confidence in the testing of ICM's. Now I have even less.
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Hammer Time
Ultimate Carjunky
/ Moderator
Nov 10, 2020, 5:00 AM
Post #2 of 4
(4217 views)
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Re: 2008 Buick Lacrosse--Cranks but No Start
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I wouldn't worry about the delayed starter engagement. That's just the PCM controlling the relay.
I would check for injector pulse and injector power supply. If you have power supply but not pulse, I would tend to blame the crank sensor.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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hawk42
Novice
Nov 14, 2020, 9:55 PM
Post #4 of 4
(4106 views)
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Re: 2008 Buick Lacrosse--Cranks but No Start
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Update--The Buick is back on the road. I decided to check the output of the Crankshaft Position Sensor at the Ignition Control Module (ICM) using my wire piercing probes, volt meter and hand turning the engine. I had neither the 3X nor the 18X signal. I checked for power to ICM with ignition on. I had a good ground but no 12V power. I checked the Ignition Fuse, 15A, No. 24 and it was blown. I replaced the fuse and the vehicle started but had a dead miss on cylinders 1 and 4. I changed position of two of the coils and then had a dead miss on cylinders 1, 4, 2 and 5. Yes it will start and run on two cylinders but barely. I replaced the coil and the ICM and it ran flawlessly, Looks like something went "south" in the ICM and it got the fuse, the coil and the 1-4 circuit in the ICM.
Thanks so much for your help with this issue.
Hammer: As usual, you were "right on" with the probable cause.
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