1990 Chevy Suburban Too much fuel

Tiny
ALJ4857
  • MEMBER
  • 1990 CHEVROLET SUBURBAN
  • V8
  • 2WD
  • AUTOMATIC
  • 219,000 MILES
I had the exhaust manifold on the passenger side replaced 4 days ago. I have also installed a new coolant temperature senson on the intake manifold. Since it was replaced the engine is running very rich. The spark plugs are black with to much fuel and if the timing is set at 0 as recomended it will not run. Right now the timing mark shows about 1/2 inch before the guide near the top of the engine.
Sunday, June 7th, 2009 AT 9:13 AM

1 Reply

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Typical symptoms of an engine that is running rich (too much fuel, not enough air) are poor fuel economy, elevated emissions (Carbon monoxide or CO), and engine may have rough idle or surge condition.

Possible causes include a bad O2 sensor, excessive fuel pressure (bad fuel pressure regulator or plugged return line), leaky fuel injectors, dirty air filter or restricted air inlet, or a defective coolant sensor that prevents the engine management system from going into closed loop mode.
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Sunday, June 7th, 2009 AT 10:35 AM

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