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Engine randomly cranks without firing

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Old 01-05-2010, 10:40 AM
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Default Engine randomly cranks without firing

Hey guys,
I got a problem with my car where it will crank but not fire occasionally (becoming more and more frequent). I have put a new battery in it (car had problem even before the battery was replaced), I have new plugs, a fuel filter with less than 4,000 miles on it, 85k on car. If I turn the key completely off and then try again, the car will usually fire right up. Once the car fires, it runs like it is brand new. I am thinking this is ignition related. Is there a relay that usually goes bad? Is there a diagnostic procedure that I can follow using a multimeter? It has been very cold here for the past month (below freezing most of the time). Any help is appreciated.
Old 01-05-2010, 11:58 AM
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Maybe sensor related. HAve you checked for errorcodes?
Old 01-05-2010, 12:22 PM
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It hasn't thrown a check engine light since this issue has began. I was thinking that could be the case as crankshaft sensors tend to cause this type of thing.
Old 01-06-2010, 08:54 AM
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You might also check your fuel pressure to see how your pump is doing.
Old 01-07-2010, 07:42 PM
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sounds sensor related to me
Old 01-07-2010, 10:46 PM
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I bought a 01 trans am 75000 miles did the same thing it was the cam sensor hope this helps
Old 01-07-2010, 10:47 PM
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Also does the tach work?
Old 01-07-2010, 11:06 PM
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The crank position sensor can go out without throwing a code. Drop the starter , spend 49 bux, replace the sensor. 49 bux and 20 minutes later, problem solved.

Trick is, no code = cps. You may get a soft, intermitent p0335/6 . scanner won't see it.

http://www.ls1.com/forums/showthread...=127798&page=3
Old 01-12-2010, 11:44 AM
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Thanks, guys. I just tried to fire it up yesterday (garaged for most of the winter), and it quite a few tires to finally start. I heard the fuel pump prime every time I fully turned the key, so the fuel pump is essentially ruled out. Besides, if it was fuel related I would think that it would sputter upon startup, but it eventually fires up like nothing happened. My water pump gaskets have been leaking, I have a feeling that coolant got into the cam sensor and screwed things up. Also, somebody asked if the tach works, and it does. Well, time to feed the money hog again lol.....

Last edited by Tuffguy610; 01-12-2010 at 11:48 AM. Reason: .




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