Misfiring

Tiny
JEFF KOSS
  • MEMBER
  • 2002 OLDSMOBILE AURORA
  • 3.5L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 225,000 MILES
This car has been sitting for three years, it was a friend of the family's so I know it was Sitting for years. They could not tell what was wrong with it and I got it for almost nothing.
2002 Oldsmobile Aurora 3.5l misfiring and running rough. Now only misfiring and will not crank. I replaced the fuel pump, and fuel filter, both coils, new plugs, drained fuel tank cleaned it out blow out fuel lines replaced all six injectors, It tries to fire but does not start. Now there is the crank and cam sensors and the possibility of timing chain jumping. Does this car have a timing mark on the harmonic balance pulley? I would to try and see if it did jump timing.
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Sunday, April 24th, 2016 AT 4:39 PM

4 Replies

Tiny
KEN
  • ADMIN
Hey Jeff,

This engine does not have a timing mark because the crank sensor reads a timer on the crankshaft. I would start with a compression test to see if you have low compression on any of the cylinders.

Here is a guide to help you out,

http://www.2carpros.com/articles/how-to-test-engine-compression

Let me know what you find

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Sunday, April 24th, 2016 AT 7:01 PM
Tiny
JEFF KOSS
  • MEMBER
Thanks for your input Ken I did a compression test the car has pretty even compression 225-230 in all six cylinders one cylinder is 215-220 was worried but this car sat for two years hopping a valve is sticking a little bit and the cam is turning ok only thing that's off is it has new plugs 4 are dark almost black and 2 are clean hardly look used I'm re placing the boots and might put the old plugs back just to see if it has defective plugs what do you guys think thank you once more
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Sunday, May 1st, 2016 AT 11:11 AM
Tiny
JEFF KOSS
  • MEMBER
Put this car back together still will not crank it fires and wants to crank but doesn't it backfires though the intake once hard enough to blow the air filter tube off the throttle body the only thing I did not replace is the crankshaft sensor will that cause it to act like its out of timing
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Sunday, May 1st, 2016 AT 1:37 PM
Tiny
KEN
  • ADMIN
I have seen on this car were the ignition module internally shorts out which act like what you are describing. This is difficult to test for, buy it from amazon so you can send it back if it does work.

http://www.amazon.com/Standard-Motor-Products-UF272-Ignition/dp/B000C802VM/ref=sr_1_2?ie=UTF8&qid=1462212111&sr=8-2&keywords=2002+oldsmobile+aurora+ignition+module

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Monday, May 2nd, 2016 AT 11:02 AM

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