I have a 96 4.3 code W 4X4. Recently I had just gotten off the interstate, and entered Saint Louis. Upon stopping at a stop light after exiting the highway I noticed a burning smell. I discovered something electronic had burned up under the hood do to the smell and smoke. After that I had problems starting it when hot. I suspected a problem with the ignition, but ruled that out trough some tests. Yesterday it failed to start at all after driving about 20 miles and letting it sit about 15min. I poured some fuel in the intake and it briefly started ran crappy then died. I got a reading of ~31psi at the schrader valve. Today I was getting ready to put on a fuel pump and tried to start it using the gas down the intake method to move it about ten feet into a garage, it started and kept running. Got a reading of ~53psi using the same method as before. Took it for a short cruise, the pulling into my driveway, I blipped the trottle and it died. I haven't done anything else to it. I have checked trough the forum over the months and just now and have seen many posts with similar problems, although I haven't seen one with the burning electronics issue. The pump is running, and the relay is functioning, and I have switched out the relay. Any one have a suggestion?

 

You really need to find out for sure if there was an electrical burnout. Also, completely go through the steps in these threads:
96+ Fuel System Diagnosis
Engine Cranks But Does Not Run

 

Here are some more pressure readings;

1st key on ~20 psi
2nd key on ~24 psi
3rd key on ~26 psi

sat for 60 seconds little change

after cranking pressure rose slightly over pre crank reading

gas in intake- ran crappy smoked and smelled like charcoal starter was burning

pressure ~35 psi

after an hour or so ~22 psi


I was hoping someone would help me find the 96+ Fuel System Diagnosis. Thanks for that. The electrical burn out is what I'm unsure about. I have not checked the voltage at the pump. All I know is I can feel and hear the relay click, and the pump is pumping some since I have variations is pressure after relieving it and taking new readings. Any suggestions on what to look at when diagnosing the electrical issue? I think there is a high likelihood there is a correlation. I have dropped the tank on this vehicle a couple times, and replaced the harness for the pump the last time I rebuilt the pump. This truck has over 237000 miles. Could an egr have anything to do with this?

The problem was a bad fuel pump. Still don't know what the burning electronics was about.

 

Glad you got it sorted out. Here's hoping nothing else crops up.