1991 Pontiac Grand Prix engine wont start

1991 PONTIAC GRAND PRIX
131,000 MILES • 6 CYL • 2WD • AUTOMATIC
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RJP1948
  • MEMBER
  • 1 POST
have replaced all sensors and a new wiring harness from the fire wall to the radiator,,,Have fire to the plugs, Have 44 to 50lbs of fuel pressure. Code reads 12 so ecm is good as it is brand new also. New icm as well. Changed the prom over also. Will try to start for a second and then quits.Have had a dia mach on here but no codes other than 12.
Mar 19, 2009 at 9:21 PM
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MMPRINCE4000
  • CAR REPAIR CONTRIBUTOR
  • 8,548 POSTS
If fuel pressure is good and you have spark, hook up a noid light to injector connector to see if ECM is pulsing injectors. If not then check injector fuses.

Also try spraying starting fluid down throttle body, if engine runs for a few seconds, then fuel issue, otherwise an ignition timing issue (crank sensor for example).

In addition to spark and fuel, you need compression to start, so check compression with mechanical gauge.
Mar 20, 2009 at 6:51 AM
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