TBI engine running rich?

I have a caprice with TBI and it is running rich. It doesn't matter if the engine is cold or hot, or whether the O2 is plugged in or not. The exaust in strong and burns the eyes. It idle rough, and gets 7-8 MPG. the spark plugs are black. 11.5 PSI Fuel pressure. It got an engine swap 3000 miles ago. Plugs, wires, and whole distrubutor, and coil were changed at same time. It ran lean when I first put in the engine.

Update:

Long story... it is an 85 chevy caprice, with 88 truck tbi system. engine is a 350. I have a Hot chip in there too. There is no MAF sensor, instead theres a MAP and I am hooking up a computor right now to read the sensors and the ECU sees it, with ALDL. hold on

Update 2:

With a leaking EGR it can't make it run rich i thought? I know it can make it idle badly. But my problem is it is running pig-rich

Update 3:

a REPLY to "Don E": 1.i will check the FP again. 2.pin hole in the fp regulator ?????? I can see the injectors splattering tons of fuel. 3 Just verified timing.4. checking TPS now .5 I plugged the PVC valve and it runs the same 6. will check the MAP

Thankyou for your help

Update 4:

FOUND THE PROBLEM!

Update 5:

the passenger side injector o-ring is leaking badly, about twice the speed of a coffie maker! Thank you all!

5 Answers

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  • 1 decade ago
    Favorite Answer

    Check your EGR valve and your exhaust sensors, and temp sensors, they both tell the computer how rich or lean to send the fuel. Get it taken care of pretty quick, if the fuel keeps going like that, especially if it's the wrong temp, it can wash your cylinders out, then you're out another engine.

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  • (A)
    Lv 7
    1 decade ago

    Could be:1.Plugged fuel return line from TBI back to tank. 2.Could be a pin hole in the fuel pressure regulator drawing fuel through the vacuum line.3 Could be a incorrectly stabbed distributor.4. Could be incorrect voltage to the Throttle possition sensor allowing a continual rich mixture.5 could have a defective or incorrect PCV valve.6.Vacuum leak at the map sensor.That is all I can think of right now, good luck.

    Source(s): me
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  • 1 decade ago

    If it doesn't change with the O2 unplugged then it must be the O2. Maybe inspect the injector spray pattern to see if it sprays or drops. Possible open injector but with an engine change you should first change the O2 and if you notice some change continue with the basics, plugs, etc.

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  • Lab
    Lv 7
    1 decade ago

    I still don't know the year. On older GM's , the ECM chip often had to be upgraded. Do you know anyone with a scanner to see what is happining regarding the input sensors? This info. would help.

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  • 1 decade ago

    Check the mass airflow sensor.

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