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Engine runabilty

Tiny
GEOINAK
  • MEMBER
  • 1993 CHEVROLET TRUCK
  • V8
  • 4WD
  • AUTOMATIC
  • 130,000 MILES
1993 chevy k1500 with 5.7 runs rough, blows excessive black smoke, poor fuel economy, no codes present? Have replaced MAP sensor.
Saturday, December 4th, 2010 AT 8:13 PM

5 Replies

Tiny
BMRFIXIT
  • MECHANIC
  • 19,053 POSTS
Black smoke running rich to much fuel check fuel pressure regulator
O2 sensors
coolant sensor
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Saturday, December 4th, 2010 AT 8:17 PM
Tiny
LEGITIMATE007
  • MECHANIC
  • 5,121 POSTS
Ok it sounds like you have a leaking or several leaking injectors. Also you may want to check the fuel pressure regulator, you may be pushing more fuel/(running rich) because of this
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+2
Saturday, December 4th, 2010 AT 8:18 PM
Tiny
LEGITIMATE007
  • MECHANIC
  • 5,121 POSTS
BMRFIXIT, makes a good point, you may not be going into closed loop, which means a bad oxygen sensor or even engine coolant temp sensor.
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Saturday, December 4th, 2010 AT 8:19 PM
Tiny
GEOINAK
  • MEMBER
  • 2 POSTS
Thank you for the quick responses. Shouldn't I be getting check engine light and codes with bad o2 sensor and/or coolant temp sensor?
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Saturday, December 4th, 2010 AT 8:43 PM
Tiny
BMRFIXIT
  • MECHANIC
  • 19,053 POSTS
Not always and you can not depend on the check engine light
you can scan data for reading
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Saturday, December 4th, 2010 AT 8:57 PM

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