Mechanics

MY TRUCK WAS RUNNING ONE DAY AND WON'T START THE NEXT.

1992 GMC Typhoon • 83,000 miles

My truck has a fresh tune up, good spark, proper timing, fuel pressure at 36psi, with the vacuum hose applied, and ran good yesterday. The only thing I changed in these two days was the gas. The truck was in storage with gas stabilizer for two years. I emptied the tank and added new gas.

The engine is being flooded with gas at start up. The spark plugs are a wet black color and the exhaust is black. I noticed the throttle position sensor was disconnected and reconnected it. Afterwards, I cleared the ECM of codes by removing the fuses and tried to start it. I can't get it running long enough to check for more codes. Please give me some ideas of what to look for. I don't know how to disengage electronic choke if exists.
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Imakeorphans
October 13, 2011.



Pull the fuel pump fuse and see if it will start. You may have sticking injectors.

Wow, I disconnected the fuel pump and the engine ran longer than it has all day. What next?

Tiny
Imakeorphans
Oct 13, 2011.
That tells me there is either too much fuel pressure to the rail (fuel pressure regulator is bad) or the injectors are leaking which is unlikely but is possible if pressure is too high. If you have a fuel pressure gauge, check to make sure the pressure is within spec. I looked and it calls for 9 to 13 psi for both the 4.3 and turbo 4.3. If you are at 36psi, you are dumping fuel into the engine. Either you have a plugged return line to the tank or as I mentioned, the fuel pressure regulator is bad.