Chevy 4.3 tbi

Fritz Maurer · Jun 6, 2023

Have this engine in a forklift, equipped to burn propane. Gasoline injectors disconnected and plugged. Do the wires need to be connected to the injectors for the engine to run? My problem is the grommet for the wires is gone, someone had glued the wires in with RTV. This recently gave way and the original grommet is not turning up anywhere, from Hyster or any auto parts store. Without this gaping hole plugged in some fashion, the engine cannot build enough vacuum to open the propane carburetor valve. If I dont have to have the wires going through there, a flat gasket for the air intake will cover the slot and seal it up.

Sprint 6 · Jun 6, 2023

Go to a junkyard and cut the injector harness off a GM TBI pickup. That grommet is the same for 4.3, 5.0, 5.7. Some 7.4 will have it, but there were 2 different throttle bodies used on the 7.4 over the years.

BarnyardEngineering · Jun 6, 2023

I had one in my 1997 C1500, first new truck I bought.

The TBI was a problem from new, but I had no idea until just before I got rid of it in 2003. Always had a random misfire that the dealer could never get rid of, so they claimed they could not feel it.

It would not run when three injectors decided to stop firing altogether. I mean it would not even cough, or sputter. Computer would not let it fire unless it got signals that enough injectors were firing.

I guess the question I have is, where do those injector wires go once they exit the TBI unit. If they're just dangling, there's your answer. Should be possible to bypass the computer on these old engines.

Chevy 4.3 tbi

Fritz Maurer

Well-known Member

Sprint 6

Well-known Member

BarnyardEngineering

Well-known Member

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