1989 gmc 15 truck engine trun but wont start i replaced the fuel pump and it still wont pump fuel i can't find a fuel pump fuse the fuel pump relay is good.

Without testing we'd only be guessing ! Do you want to replace a bunch of parts till the problem is fixed ? Hooking up a scanner an looking at engine management system sensor's (data ) inputs to the engine computer would be the first place to start. If you don't have the ability to do this , suggest you take it to a qualified repair shop . Or learn automotive Engine system diagnostic's . A lot of thing's could cause the problem your having . Do you know how to test automotive electrical an electronic system's ?

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Timing. Your probably not TDC.

Have the shop start or continue testing things,
that is why you took it there

Don't tell us they can't find anything
We hear that every day here

Fuel pumps fail both mechanically & electrically
& can be tested many ways.

believe or not i may be under the drivers seat. I don't know why.

The fuel pump relay gets power from the ECM fuse which also powers the computer. So if the check engine light does not come on when you turn the key on, it could be the fuse. But it could also be the pump relay.

Backfire on acceleration could be caused by a worn lobe on the camshaft especially on a small block Chevy engine. You have to remove the valve covers and check the lift of each push rod. Sometimes it's quite obvious but sometimes it requires close inspection and even measuring the lift.

make sure you have spark

you just need to replace the fuel filter... quick and cheap fix

maybe your feul pumps not working to test just trun key to on position but dont try to start listen to hear if feul pumps is runnig

Two things can cause that # 1 is the module in the distrubtor # 2 is the ECM.