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7.4L tbi + fuel problems...injectors dump gas (full open delivery)

36764 Views 22 Replies 9 Participants Last post by  Napoleon Solo
7.4L 1992 GMC sierra 1ton
--Problems just started, i have to fully depress pedal to start
--injectors have been replaced, they pulse during ignition...when started, injectors spray constant, dumping fuel
--NO o2 sensors on the manifold

**NO engine codes, only code 12
**Can't figure out why injectors are not pulsing, idle revs up to 1,500
--ECM replacement? TPS and IAC need to be replaced?
--everything on the harness gets the correct Voltage.

I'm thinking that the ECM needs to be replaced, the IAC and possibly the fuel pressure regulator.
Very hard to maintain an idle now on the truck and the conical spray pattern is thick and constant when the truck is running.

No MAF sensor or O2 sensors on this TBI 454's a 1ton.
again, i replaced the injectors but it's not fixed yet.
Played with the idle screw to no avail as well. :grrrrrr:
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I have the exact same issue with my truck. Your post caught my eye because I just replaced my radiator a few weeks back and coincidentally or not my 1500 rpm idle issue started shortly thereafter. Can the coolant temp sensor really cause this?
My truck is a 92 GMC 7.4l 2wd.
Thank you,

Solo out...
Absolutely. If the sensor fail in the hot mode once you attempt to restart with cold engine it will be lean and very hard to start. If it fails cold it will continuously dump fuel even once it's warmed.
Napoleon, welcome to the Forum. Yes, pre-95 it can because the programming is heavily dependent on engine temp.
Excellent. Thanks gents, I’m going to fix that tomorrow.
Solo out..
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