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 engine...it'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:
Pretty sure those don't have a crank sensor. Sounds like the ECU might be running in limp mode, or that your pressure regulator is bad. Didn't see but have you checked your fuel pressure yet? High pressure = more fuel through the injectors.
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