1995 5.7 tb fuel problem....thanks

[kern]

Hello everyone...I have a 1995 yukon that I'm having some problems with. It will start cold with no problem....but once warmed up....no go. IT will crank just fine but acts like there is no fuel getting to the injectors. I have change out the fuel filter and replace plugs and filters. When i turn the key I can hear the fuel pump running and think i can smell gas at the carb. after much cranking and after some oil pressure builds up it will start.

1. does it sound like the fuel pump?

2. where is the fuel pump relay?

3. if i get a fuel pressure guage where is the best place to hook it up near the carb or near the filter?

thanks all, kern

[GNW]

FIND THE FUEL PUMP RELAY!!!!! You write as if the oil pressure sending unit by-pass for the fuel pump is the only thing allowing the fuel pump to run. Not to jump to a diagnosis, the fuel pump relay on GMs usually has red, gray, orange, and green/white or green wires. you can probe at the gray wire and see if you get power for 2 seconds when you turn on the key. If you do not you have to check for the 2 powers with the key on and you need to check for computer grounding of the relay. To check for ground, turn the key on and probe the green wire (test light to battery positive) in the first 2 seconds that the key is on. If the light lights the computer can control the relay. If you have the two powers to the relay and no output the relay is bad. On the wiring colors I might be close to their colors and functions. Consult a wiring diagram if need be. The relay should be under the hood. Other ideas besides the relay make be fuel pressure bleeding off after the truck is shut off. On a TBI I haven't seen too many flooding problems. Maybe an ECT showing low temp. when warm. If you get a fuel pressure gauge, you will need some adaptors. At the TBI is a pain,but you do not have to flatback it and have fuel running down your arm. At the filter on the output side is okay. You need to look for instant fuel pressure, sustained fuel pressure while cracking, and how well it holds the fuel pressure after the key is turned off. On a TBI the fuel pressure should be around 11-13 PSI. good luck