Intermittent no start/run, lots of tests done!

Tiny
STANGIN
  • MEMBER
  • 1993 BUICK REGAL
  • 133 MILES
I have a 1993 buick regal with 3.1 liter. Car started stalling off and on over two week time period. Eventualy the car would not start at all. So far I have tested the crank sensor, map sensor, camshaft sensor, the ecm, and ignition module. Also did secondary resistance test on the coils. It has spark, it has 42 lbs pressure at the rail, the regulator is not bad. The weirdest thing is the only thing that would get the car to start is to choke off the throttle body manualy. After started the car runs great, and then eventualy after so many restarts it will not start once again. Im lost!
Tuesday, May 29th, 2012 AT 1:20 AM

8 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Check the coolant sensor. It may be out of spec.

Roy
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Tuesday, May 29th, 2012 AT 1:22 AM
Tiny
STANGIN
  • MEMBER
  • 5 POSTS
Good point, will do right now
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Tuesday, May 29th, 2012 AT 1:26 AM
Tiny
STANGIN
  • MEMBER
  • 5 POSTS
Coolant temperature sensor checked out good
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Tuesday, May 29th, 2012 AT 1:39 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
How did you check it?

If you disconnect it, it should turn on the cooling fan thinking it is overheating.

If you short the 2 wires together, it should go full rich.

Roy
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Wednesday, May 30th, 2012 AT 10:51 PM
Tiny
STANGIN
  • MEMBER
  • 5 POSTS
Well 1st time I unplugged it, then I checked the resistance while heating it up, didnt seem quite right so replaced it, still have same problem. Id like to add couple things, egr valve checked out good, it isnt bad gas, but the weirdest thing is today I swaped out the computer with another one out of a running vehicle that had matching numbers. Didnt fix the problem but when I put that one back in the running car it caused it to not start well, it would do same thing this car does for a few times. Disconnected battery for 10 mins and it went back to normal. Also, yesterday I had car running all day, left it idel hour at a time for few times, at least 20 restarts, and drove for about 20 miles. Then randomly I went to start it and same problem, rrrrrr!
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Thursday, May 31st, 2012 AT 12:45 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Did you change the prom form your computer to the donor computer?

Roy
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Thursday, May 31st, 2012 AT 1:02 AM
Tiny
STANGIN
  • MEMBER
  • 5 POSTS
Wow, I feel like an idiot right now cuz I didnt even think of doing that, I will try that tomorrow, on another hand if no different, do you think something is sending a short back to the computer?
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Thursday, May 31st, 2012 AT 2:01 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Not likely. Try the prom first.

Roy
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Friday, June 1st, 2012 AT 1:49 PM

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