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Fuel injector?


Browning

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Buddy of mines truck, 91 Chevy Cheyenne 1500, 4.3. Its been lugging and missing pretty bad lately. I put new plugs, wires, dist. cap and rotor on it. didnt change the way it ran at all(and the plugs were pretty hit). Anyhow, after changing it I overlooked all the vacs, none are leaking. But what I did notice was the drivers side injector(its only got two) wasnt spraying even. In fact, the back side was spraying, but the front drips. Whats the odds that the injector is the problem, is it possible the drip is causing the truck to flood slightly? What is does it idle rough, and its jerky when giving it a little fuel. Also, when trying to go up slight inclines, its like there is no power. If it will help, Ill post pics of the plugs that came out of it. thanks
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Guest 78novaman

You pretty much answered your own question :)

 

Just clean out the TBI (you can try some Lucus Oil injector cleaner) or swap it with a junkyard one and it should be fine.

 

I'd replace the fuel filter as well. Odds are if the injector is clogged the filter is.

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Used TBI units for a 4.3 go for about 30 on ebay, if the injector is hosed, it would be alot cheaper than buying new injectors.

Also, have you replaced the EGR valve? those have a tendancy to get funky over time, and will stick open, making it idle like crap.

If he has a wad of cash to blow, you can get a new bolt on holley unit with injectors for about 400 from summit or jegs.

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Not at all. You will need a gasket set though.

Im not sure if this truck has matched or unmatched injectors, make sure you check before you swap em out. Some of the v6s had one injector slightly larger (+5lb) due to a fuel distrubution problem.

Make sure you clean em up good, and note what color they are.

 

Color code on inj Engine Flow lbs/hr @ 13psi TBI bore GM part #

Black/White 2.8L 33 35mm 5235430

Yellow/Blue 4.3L 45 43mm 5235203

Green/White 5.0L 40 43mm 5235279

Orange/Black 5.7L PU 55 43mm 5235206

Yellow/Brown 5.7L CopCar 65 43mm 17084327

Blue/Black Late BB PU 80 51mm 1708430

D Red/D Blue Early BB PU 90 51mm 5235231

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