Car will shut off while driving and can be difficult to fire
10-13-2012, 10:59 AM
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Car will shut off while driving and can be difficult to fire I have a 2000 Z28 with bolt-ons and a cam and my recently started just shutting off while driving. All electronics will work but the ignition. When the motor shuts down while driving I have let the clutch out to see if it will fire but nothing. It just bogs down and turns the motor over. Also, when I pull over and try to start it, everything works when I turn the key to run, when I turn the key to 'start' it cranks the motor but it will not fire. I have had to take the key out and put it back in up to a dozen times before it fires up. My alternator has recently been changed and my battery is at full power. I don't think it's the VATS as the car does crank. I have 80K on the clock and the car was tuned when the cam went in around 63K. Could my PCM be going out? Any and all help is appreciated gents.
10-16-2012, 11:39 AM
#7
Yes it is. A bad crank sensor will cause all kinds of running issues. From not starting, to dieing while driving, to missfires at weird rpm ranges. Get an ac delco one though as the aftermarket ones in my experience suck lol.
Well this may or may not be the same case as the op's. If the car runs fine with no issues then it sounds like you cam sensor. Basically what happens is when the motor is trying to fire it uses the cam sensor to see where the timing should be. If the sensor is bad it doesnt know when to fire thus hard starting and long cranking. The next time you turn the key the pcm will reverse the timing to see if that works... Once the engine is running the pcm knows where the timing is so the motor runs fine. Thus a bad cam sensor will usually just show up at a startup whereas a bad crank sensor will show up driving as well.
Well this may or may not be the same case as the op's. If the car runs fine with no issues then it sounds like you cam sensor. Basically what happens is when the motor is trying to fire it uses the cam sensor to see where the timing should be. If the sensor is bad it doesnt know when to fire thus hard starting and long cranking. The next time you turn the key the pcm will reverse the timing to see if that works... Once the engine is running the pcm knows where the timing is so the motor runs fine. Thus a bad cam sensor will usually just show up at a startup whereas a bad crank sensor will show up driving as well.
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10-17-2012, 11:56 AM
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Just tried it and no dice. I did notice that when I got my starter out of the way, the old wire loom to the crank position sensor was dry rotted and cracking but the wires were in perfect shape. No cracks or breaks in the insulation of each wire. Replaced the wire loom and put it all back together. Cranked it and it would not fire, just turns over. Any other ideas?
10-17-2012, 05:10 PM
#10
You need to do some diagnostics before just replacing parts. That will get expensive real fast.
I haven't seen where you said you checked for:
Spark - First, I would check that you are getting spark out of the wires.
Fuel - Get a fuel pressure gauge and see what you are getting at the rail. You can rent one free from auto parts store
The best time to test is when it won't start on you. A faulty ignition relay is fairly common on these cars. Will cause no spark. You can swap with your A/C relay to test.
I haven't seen where you said you checked for:
Spark - First, I would check that you are getting spark out of the wires.
Fuel - Get a fuel pressure gauge and see what you are getting at the rail. You can rent one free from auto parts store
The best time to test is when it won't start on you. A faulty ignition relay is fairly common on these cars. Will cause no spark. You can swap with your A/C relay to test.
10-17-2012, 07:45 PM
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THANK YOU!!!! I had already tested fuel. I swapped the ignition relay with my starter relay to test it, car would not crank....BINGO! Thank you lt1pwr1, if I'm ever in Michigan, I will be sure to stop through and buy you a beer.
Last edited by Consultant0311; 10-17-2012 at 08:11 PM.
02-23-2013, 01:57 PM
#13
I need to bring this one back up as I have never solved my issue as I am not getting any codes. I did get a cam sensor code, replaced the sensor but kept getting the code. Eventually I had set it up to never throw that code and the problem went away for a while but now its back. I have switched relays, didn't work. This problem never started until I had a VATS(BCM) problem a year ago. Where do I go now? Crank sensor, bad bcm, alternator not providing enough voltage? Need some help here.
02-27-2013, 09:49 AM
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I need to bring this one back up as I have never solved my issue as I am not getting any codes. I did get a cam sensor code, replaced the sensor but kept getting the code. Eventually I had set it up to never throw that code and the problem went away for a while but now its back. I have switched relays, didn't work. This problem never started until I had a VATS(BCM) problem a year ago. Where do I go now? Crank sensor, bad bcm, alternator not providing enough voltage? Need some help here.
I found out mine was due to the wiring Harness over the pass strut tower. I had done the Hidden wire mod more then 7 years ago running it through the wheel well. On a whim after trying most everything posted here I took the tire and wheel well plastics off, cranked the car and found I could make the car shut off by shaking the harness. Tested 10 times, every time I could make the car shut off. I moved the harness's back to the default section since I don't show the car anymore, checking my connections and haven't had an issue since. Been almost a year since it has done it.
