1991 Buick Century engine dies

Tiny
PERKINS42
  • MEMBER
  • 1991 BUICK CENTURY
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 110,000 MILES
I am a diesel mechanic, having a tough time figuring this one out. The problem started a couple of months ago, car would die intermitantly after being driven for awhile on hot days. It would always restart and make it home. Now the car will start and idle fine, first thing in the morning, and die after runing for a couple of minutes. Pressing the throttle will usually kill the engine immediately. Once it has died, it will not restart until the engine completely cools down (engine never does "overheat" when running).

Tested the ignition control module-bad; replaced. Replaced spark plugs. Checked injector harnesses with noid light-all looked good. Replace fuel filter. Fuel pressure is steady at 45psi. Checked TPS passed all tests listed in All Data. Removed and cleaned IAC. Removed and cleaned mass air flow sensor. Checked spark when engine won't start-each wire throws a bright blue spark about 1'' long.

When the engine does start in the morning it idles very smooth for the very short time it does run.

I look forward to any reply

Thanks
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Sunday, August 22nd, 2010 AT 2:01 PM

14 Replies

Tiny
JALOPYPAPA
  • MEMBER
I had a similar problem this summer with my '92. It would run fine but liable to quit or not restart when hot. I replaced the crank sensor and all has been fine since. Not an easy job on this car, since it's behind the crankshaft pulley, and spacing the air gap with the reluctor vanes requires either (1) a $600 alignment tool or (2) a.020 feeler gauge and A LOT of patience.
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+1
Monday, August 23rd, 2010 AT 11:52 AM
Tiny
BUDDYCRAIGG
  • EXPERT
I'm leaning towards the crank sensor also.
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Wednesday, August 25th, 2010 AT 1:48 AM
Tiny
PERKINS42
  • MEMBER
I am sold on the crank position sensor too, I will let you know the results.

Thanks
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Wednesday, August 25th, 2010 AT 1:32 PM
Tiny
PERKINS42
  • MEMBER
Replaced the crank position sensor tonight, no change still dies after warmed up. I also removed the fuel rail and injectors and cleaned, really were not that dirty.

Out of ideas, any one have a suggestion?

Thanks
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Thursday, August 26th, 2010 AT 11:30 PM
Tiny
BUDDYCRAIGG
  • EXPERT
Will it hit on ether when it wont start?
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Tuesday, August 31st, 2010 AT 9:44 PM
Tiny
PERKINS42
  • MEMBER
Yes, will run on starting fluid when it won't start
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Tuesday, August 31st, 2010 AT 10:29 PM
Tiny
BUDDYCRAIGG
  • EXPERT
That doesn't make sense.

You get a noid light flash.
And you've got good fuel pressure.

But apparently fuel is the problem.
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Wednesday, September 1st, 2010 AT 3:00 AM
Tiny
PERKINS42
  • MEMBER
After the engine warms up and won't start, you can get it to fire and run very rough on starting fluid. I think the timing is off after it warms up. It coughs and blows smoke out of the intake when its cranking with out starting fluid. I just can't figure out why the ignition timing changes after its warmed up (if that is what's happening). I am starting to think its a ECM problem, don't know what an ECM costs, and if its worth trying or not.

Any ideas?
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Thursday, September 2nd, 2010 AT 11:58 PM
Tiny
BUDDYCRAIGG
  • EXPERT
Sorry I didn't see your last message.
Do you have a good blue spark when this S$#t is going on?
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Monday, September 27th, 2010 AT 1:45 AM
Tiny
JALOPYPAPA
  • MEMBER
With another car, I recently had a loose timing chain that at first let me drive a mile or two before I saw driveability problems. It pretty quickly got much worse, though.
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Monday, September 27th, 2010 AT 1:29 PM
Tiny
MIDASTOUCH1953
  • MEMBER
I too have a 91 Century. Replaced all the basics. The only diff between yours and mine, is that mine will run "perfect" for a day or 2, and then just die when I get to a red light, or come to idle. Recently replace the Mass Air Flow Sensor, and used to intake cleaner as well. This seemed to help alot, but 2 days later, it started quitting again, BUT only at an idle. Replaced idle speed motor. Didn't help. After hearing what perkins42 said about all he tried, I'm really leaning towards the ECM. My car does it's thing hot/cold, and when it's running right, she's smooth as silk. But just before it's ready to shut down, she seems to idle rough, and either acts like it's starving for fuel, or spark. Just thought I'd add these few tidbits, and I'll look forward to us helping each other solve this prob. Thx guys, and good luck! Keep posting results, plz!
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Monday, January 10th, 2011 AT 3:49 PM
Tiny
MIDASTOUCH1953
  • MEMBER
****FOOTNOTE****
Also, when my car DOES stall out at an idle, it does immediately restart. Sometimes stays running, sometimes quits 4-5X before it stays running. BUT! I have never had it NOT start, beit hot/cold.
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Monday, January 10th, 2011 AT 3:55 PM
Tiny
PERKINS42
  • MEMBER
Finally got my car running. I replaced the timing chain, sprockets and tensioner. The old chain/sprockets were very loose compared to the new set. Started car ran great, then same problem came back and it died after getting warmed up. After working on this for a few days, the problem progressed to the point it wouldn't even start when it was cold. With a remote starter button I started unpluging injectors and trying to start. With #2 inj. Unpluged engine started and ran good (other than missing on #2). Got a new injector and replaced #2, now car runs good. After looking at a schematic I learned the ECM fires the injectors through 2 pins. 1 pin is for 1, 3 and 5 and the other grounds 2, 4, and 6. Injector #2 was shorted internally to ground causing 2, 4, and 6 to over fuel. Finally I have a running car again. I do think the old loose timing chain was stretching when it got hot and caused problems as well, it was due for the new timing chain and sprockets.
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Tuesday, January 11th, 2011 AT 12:00 AM
Tiny
BUDDYCRAIGG
  • EXPERT
Never heard of that before.
Thanks for posting your final outcome so we can all learn from it.
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Tuesday, January 11th, 2011 AT 1:53 AM

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