91 sonoma starts and sputters out, see if you can figure this one out!!

[dcemmett]

I have a 1991 GMC sonoma 2.8LV6 with 194,000 miles on it. I was driving on the interstate on saturday and it died suddenly. There is 3/4 tank of gas. It will turn over and start, but won't run unless I pour gas in the throttle body, then it runs smooth. Everyone around here is stumped considering what has been checked/replaced, which is:


new fuel pump 1 month ago
new pickup coil, ignition module, rotor and cap 1 month ago
another new ignition module 1 day ago
new fuel filter 3 days ago
new fuel pressure regulator 1 day ago
checked wiring around ECM/Dist, no breaks or loose wires
checked fuel relay, works well
installed new injectors, didn't make a difference, so put old ones back
checked and cleaned all fuel passages in throttle body and fuel lines

The injectors are spraying a light mist, but it does not keep the engine going, unless I pour gas in the throttle body. We have checked electrical and physical fuel delivery systems, and cannot figure this one out. I am 500 miles from home(at a friend's) and my mechanic, but on the phone, he can't figure it out either.

Could the fuel pump be bad? It hums when the ignition is turned, and fuel is getting up to the engine, just seems like not enough? Thanks for any opinions/advice!!

[dcemmett]

Just pulled the fuel pump, and it is in good shape, it has to be something around the throttle body....

[bajatruck21]

My truck did the same thing i was running in between the suggested fuel pressure, but i figured out that the engines have to be running at top fuel pressure. Mine runs at 61 psi, try that out

[old_master]

Originally Posted by bajatruck21

My truck did the same thing i was running in between the suggested fuel pressure, but i figured out that the engines have to be running at top fuel pressure. Mine runs at 61 psi, try that out

1991 4.3L VIN Z is TBI, (Throttle Body Injection) fuel pressure spec is 9 to 13psi. Your 1997 4.3L VIN W is CMFI (Central Multiport Fuel Injection) and fuel pressure spec is 60 to 66psi. Totally different fuel systems.