Idle problems an rich exhaust

Tiny
BMXWAYNE
  • MEMBER
  • 1993 PONTIAC SUNBIRD
  • 4 CYL
  • FWD
  • MANUAL
  • 231,000 MILES
I have a 1993 pontiac sunbird and it has been idling rough stalling at idle and have gotten a rich exhaust code also have a drop in mpg
Saturday, December 18th, 2010 AT 5:09 PM

10 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,640 POSTS
What code did you get? When was the last tune up? Have you checked the fuel pressure regulator?
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Tuesday, December 21st, 2010 AT 3:45 PM
Tiny
BMXWAYNE
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It was code 45 I cleared the code and it has not come back but still having problems last tune up is pretty recent how can I check the fuel pressure regulator there is no connection for a pressure gauge
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Tuesday, December 21st, 2010 AT 11:36 PM
Tiny
JACOBANDNICKOLAS
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45 oxygen sensor rich exhaust. It could be a bad O2 sensor. As far as the fuel pressure, you need a "T" adapter to place in the fuel line if there is no schrader valve.
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Wednesday, December 22nd, 2010 AT 1:31 PM
Tiny
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Is there anyway to test the 02 sensor
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Wednesday, December 22nd, 2010 AT 10:23 PM
Tiny
JACOBANDNICKOLAS
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Yes, you need to check for resistance.
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Thursday, December 23rd, 2010 AT 1:08 PM
Tiny
BMXWAYNE
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How much resistance should there be I do have an analog multimeter
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Thursday, December 23rd, 2010 AT 10:27 PM
Tiny
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I did more research. I want you to check the O2 sensor for a ground issue. I have attached a schematic. Here is what I need you to do. You need to check voltage to the sensor. You should get a.45 volt reference power supply from the control module. Check that. Also, with the engine warmed up, you should get between.35 and.55 voltage reading off idle.

As far as the wires you are looking for, ECM terminal C7 is a purple wire from the ECM (power supply) and C8 is a tan wire (ground). Based on everyting I read, that sounds like where the problem is coming from. Just keep your fingers crossed that it is a bad ground.
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Sunday, December 26th, 2010 AT 6:21 AM
Tiny
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Ok o2 sensor was bad and I replaced it now I am getting code 33 map sensor circut signal voltage high/low low/high vacuum as described by chilton manual
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Saturday, January 1st, 2011 AT 5:39 PM
Tiny
JACOBANDNICKOLAS
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Are you able to watch the MAP sensor's reactions via your scanner?
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Saturday, January 1st, 2011 AT 8:10 PM
Tiny
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No I cannot it is an obd 1 system and now my car is giving me 7 codes could the prom chip be bad
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Wednesday, March 2nd, 2011 AT 2:49 AM

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