1989 Chevy Silverado Excessive Fuel

1989 CHEVROLET SILVERADO
292,000 MILES • V8 • 4WD • AUTOMATIC
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DLESATZ
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"I have an '89 Chevy 4X4 1500 w/350 and auto trans. It used to get good mileage,17-19mpg and now it is doing very poorly 1/8 of a tank to 30-35 miles. I have replace the complete fuel system from the TBI to and too include the tank. I have checked all the sensors and they seem to be in spec. I have installed new injectors and regulator in the TBI. But hot or cold, it stills smells rich coming from the exhaust. I really could use some help here. " All fuel lines and the fuel pump have been replaced. Checked for intake manifold vacuum leaks a TBI and heads..no change in idle.
Nov 27, 2009 at 5:15 PM
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RASMATAZ
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Since you've check the CTS/O2 sensors and it checked out -try checking the fuel pressure if its within specs, also inspect the fuel return line for blockage
Nov 27, 2009 at 5:37 PM
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CCOBURN
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when mine was new ~1991 or so, the dealer replaced the coolant tempo sensor on the thermostat housing.

It can causes the ECM to think the coolant is 100% cold or 100% hot in the range of the sensor. If the ECM thinks the coolant is cold, it will run in warm-up mode which is really rich. It was also having a hard time starting.

Also, you said you checked the sensors. How about the sensor plugs and wires?
Dec 8, 2009 at 10:37 PM
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