Fuel Problem on 89 GMC S-15

[TNOleRed89]

My 89 Gmc S-15 wont start without pouring gas in the throttle body opening then will only run a few seconds and die. Here is some of what i have replaced: fuel pump, fuel filter, fuel pressure regulator, fuel pump relay, fuel injector, every sensor on the engine( map, coolant, oxygen etc) plus i replaced a couple things on the throttle body unit. Also before i realized it was a fueling problem i replaced ignition module, computer and im sure something else as i have replaced everything i know of on the engine. I actually replaced the entire throttle body assembly with another used unit off of a truck that my brother in law has that runs good but had a rod knock so i know its a good unit. I drove it a couple days with this used throttle body and it ran great before it started the problems again. In the beginning it would start and run good until it warmed up then the coolant light on the dash would come on ( even though it isnt running hot) and then not long after it would start jumping and act like its running outta gas. when it started the jumping and running outta gas thing the shift light on the dash flickered on and off as well making me think maybe an electrical problem but i know its not spraying fuel in the throttle body. the fuel pump turns on for a couple seconds with the key like its suppose to. and with the fuel injector out if you turn the key on all sorts of gas dumps into the throttle body. So i am stumped, any ideas. It is a 1989 S-15 with a 2.5 engine. Thanks

 

[Molson02536]

My 89 Gmc S-15 wont start without pouring gas in the throttle body opening then will only run a few seconds and die. Here is some of what i have replaced: fuel pump, fuel filter, fuel pressure regulator, fuel pump relay, fuel injector, every sensor on the engine( map, coolant, oxygen etc) plus i replaced a couple things on the throttle body unit. Also before i realized it was a fueling problem i replaced ignition module, computer and im sure something else as i have replaced everything i know of on the engine. I actually replaced the entire throttle body assembly with another used unit off of a truck that my brother in law has that runs good but had a rod knock so i know its a good unit. I drove it a couple days with this used throttle body and it ran great before it started the problems again. In the beginning it would start and run good until it warmed up then the coolant light on the dash would come on ( even though it isnt running hot) and then not long after it would start jumping and act like its running outta gas. when it started the jumping and running outta gas thing the shift light on the dash flickered on and off as well making me think maybe an electrical problem but i know its not spraying fuel in the throttle body. the fuel pump turns on for a couple seconds with the key like its suppose to. and with the fuel injector out if you turn the key on all sorts of gas dumps into the throttle body. So i am stumped, any ideas. It is a 1989 S-15 with a 2.5 engine. Thanks

Try replacing your fuel pump relay, it should be located on the firewall just left of the brake boost. (passenger side) There are two relays there, you can swap them with one another and see if that helps.

Good luck and keep us posted. Start with that since it looks like oyu have gone through the whole truck already.

 

[TNOleRed89]

Replaced that just yesterday didnt effect it one bit..... This relay was on the drivers side inner fender but i pulled it and brought to the auto parts place and told them i needed a fuel pump relay. I dont remember seeing any relays in the location you said. This truck is a 2.5 4 cylinder truck. I will look next time im over my mom inlaw's as that is where the truck is currently. But anyway im pretty sure the relay i replaced yesterday was the fuel pump relay. Thanks