1993 chevy k1500 with 5.7 runs rough, blows excessive black smoke, poor fuel economy, no codes present? Have replaced MAP sensor.
Dec 4, 2010 at 12:13 PM
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BMRFIXIT
✓Experienced Mechanic
19,053 POSTS
Black smoke running rich to much fuel \check fuel pressure regulator
O2 sensors
coolant sensor
Dec 4, 2010 at 12:17 PM
LEGITIMATE007
✓Experienced 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
Dec 4, 2010 at 12:18 PM
LEGITIMATE007
✓Experienced 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.
Dec 4, 2010 at 12:19 PM
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?
Dec 4, 2010 at 12:43 PM
BMRFIXIT
✓Experienced Mechanic
19,053 POSTS
Not always and you can not depend on the check engine light
you can scan data for reading