[Mr.Fixxit]

My brother has a '92 S10 Blazer 4.3 Vortec V6. Drove home from work today, ran fine according to him ( Plus I saw him drive in and seemed to be running fine ). He shut the truck off, and about 45 mins later he went to leave, it wouldn't start. It cranks and has spark. I've worked with cars for 15 years, but am still getting the grasp of fuel injection. Carbs are my specialty. I think it's the relay, because I don't hear that "click" or the whine of the fuel pump, or maybe a fuse? I could really use some help, thnx in advance.

[LATECH]

on the back of the motor where the fuel lines come in there is a fuel pressure test port. It will have a little black cap on it. Use it to check the fuel pressure. I dont have the spec for the pressure on hand, but if is too low the injectors wont spray.They are electronic injector solenoids with poppet style injectors. meaning even if the solenoid is turning on, the injector wont spray untill the pressure is high enough.
If there is no pressure then move on to checking the electrical system for its 2 second prime pulse from the ECM , then the OP switch circuit for maintaining pump voltage after start.Check for ANY pressure first.then go from there.

[Richiehd]

Sounds like fuel pump, common GM issue. Bang on the bottom of the tank while cycling the key on and off, Somtimes it will start and run, so you can get it in the shop or back to the house.

[LATECH]

This post has been moved to the Modern Engine Electronics section.

[alkey]

if i remember correctly on that vehicle the fuel pump relay and ac relay are the same part number.if your blazer has ac you can switch relays to see if relay is problem.most likley fuel pump.Good Luck