Mechanics

96 4.3L FUEL INJECTION ISSUE<
1996 GMC Jimmy • 250,000 miles

I have replaced all the fuel system up to the fuel meter body, good fuel pressure the injectors have power to each. New pressure sensor, crank sensor I have done complete tune up. Dont understand why two of the injectors have constant power with ignition on but strobes when you crank it over. Before I did the work on it. Would run but after a few min hot or cold it would stall but if you feathered the pedal you could keep it running. When going down the road it would stall when you stopped suddenly or at a light. When it stalled in idle (hot)it took a cool down period before it would start again. I replaced fuel tank, pump, filter and relay. Now it wont even try to start plenty of fire air and fuel to the fuel meter body. Wtf im stumped. Need more than one thing to test. Unless I have one option. Please help.
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Donnie7
May 4, 2012.



Any codes? What is the exact fuel pressure? There is 1 12 volt feed to all injectors and the return to the pcm is toggled.

Roy

I did not get any number codes just flashing CAT o2s EGR HTR and EVA can't get a running fuel pressure. Before it was 2 psi running so I replaced the pump tank and filter, what will cause two injectors to have a constant power whe ignition is on

Tiny
Donnie7
May 4, 2012.
Might have a bad computer, where did u get the crank sensor? And what was the fuel Pressure after u changed the pump?

Tiny
Mikederouin88
May 4, 2012.
The sensor is a BWD. With power pulsing at each injector is right what else is controling fuel flow. I'm testing the fuel pressure in the morning. That pressure should be 43 - 56 psi not running, running it should drop to 3-10 psi is that correct

Tiny
Donnie7
May 4, 2012.
Just asking how would the crank shaft cut off fuel completly? And can you tell me what the letter codes mean that I got

Tiny
Donnie7
May 4, 2012.
Pressure should be 55-62 minimum.

What side of the injectors are you measuring? There should be 12 volts all the time to the injectors. The return to the computer are what is toggled.

Flashing check engine light is a missfire code. You did not list this in your findings.

Roy

The check ingine light is solid not flashing and I'm testing the conection at the top of the meter body going one by one with test light cranking it over for each.

Tiny
Donnie7
May 4, 2012.
Also this the CSEFI so I'm testing at the electrical conection I have not removed the plenum yet but like I said with test light I get strobes to all injector should it show a constant light for all when ignition is on.

Tiny
Donnie7
May 4, 2012.
No, it should be toggled by the computer according to load.

Roy