1997 GMC Sierra 5.7 Vortec, replaced the fuel pump, fuel filter, spider injector. Still not getting fuel past the spider. fuel pressure is 10 psi! What could be wrong

A fuel filter won't clog completely in 3 years
and won't get you down to 15# if it did

What is fire?

Voltage to pump or ignition spark?

What about pressure regulator?

If the 8th letter of the VIN # is W which i bet it is than your fuel pressure is to low.

This engine uses a CPI unit to deliver fuel to the cylinders. The CPI unit consists of a central injector that feeds fuel to the poppet valve that are right above the intake valves. The poppet valves require high fuel pressure in order to open and deliver fuel to the cylinders at start up.

The reason why it starts and runs if you add a little gas through the throttle body is that once the vehicle is running the intake is under vacuum. The poppets can open with less fuel pressure in a vacuum. This is a real common scenario with these style injection systems.

A new good quality fuel pump (a/c delco or delphi are good pumps) and your fuel pressure should be back into spec of 58 psi or more and the vehicle should fire right up. Make sure you replace the fuel filter when you replace the pump.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

check the fuel pressure with a guage. it should MAINTAIN 55-60 psi or the popits will not work properly on the cpi. fuel pumps and sending units fail on these all the time and even know you have some pressure at the test port you may not have 55-60 psi. trust me ...ck it with a guage. good luck!

I would check to see if the injectors are firing. Most injectors are a pulsing ground type. So you can use a test light to check them.

I have 1993 gmc 4.3 vortec v6 turns over but want start. replaced fuel pump, fuel pump regulator ,ecm, tps, coil

Hello frankdoiron: My name is Roger and I will help you. If the fuel pressure is not 60-66 psi. the engine will not run right or will no start. At 55 psi. the engine will not start. Unless you have a injector that is stuck open I would look at the fuel pump as the problem. I would also change the fuel filter the same time you replaced the fuel pump. The warranty on the pump would be void if you do not replace it at the same time.
Please rate the answer you received. This is how we know your answer helped. Should you need further help please just ask. Thank You for using Fix Ya. Roger

Fuel pressure regulator and spider injector is what i know it as.

Check the fuel pressure at the Shredder Valve, You should have 60PSI to 65PSI upon start and should drop about 5PSI when running. If your fuel pressure is good then it may be a bad injector system. The fuel injector spider system that the vortec has are know to go bad, from the fuel pressure regulator to the puppet fuel valves. Change the fuel filter first if it has not been changed yet and have the fuel pressure check. Good luck and keep me posed. Note: it's been know that spraying ether to start the vortec with the spider injector system has got the puppet valves to catch fire and melt the ends of the puppet valve leading to the replacement to the whole system. Good luck and keep me posted, be glad to help.

You said you have fuel pressure but what is it? It has to be 55 psi or it won't even try.

i would check the cap and rotor if it has spark and 40 lbs of fuel pressure if cap and rotor are ok check for injector pulse thats the only other thing it can be