Just put in new fuel pump two weeks ago, than started bogging on hard acceloration. Checked PSI fuel is 51, doesnt go down on accelaration.

Mechanic says need to replace fuel pump again its bad. Mechanic pinched return line pressure only went up to 54, he said it should go to 80. That was his reason for fuel pump.

Can drive if you are easy on gas pedal.

Im thinking pressure regulator, just dont want to throw parts at it.

Truck is 1996 vortec 5.7 w/ 200,000 miles.

 

Is the pressure checked before or after the Fuel filter?
Maybe it is plugged.

 

I replace that before fuel pump, brand new. checked psi at fuel rail.

 

Welcome to the forum. "Just put in new fuel pump two weeks ago, than started bogging on hard acceloration" and why won't you suspect the new fuel pump? Were those fuel pressure measurements with engine running? What was the original concern with the old fuel pump?

 

Ran fine for 2 weeks than started bogging. Pressure is 51 with key on or running. Changed fuel pump because was hard starting sometimes, mechanic said low pressure.

Thanks for replies and welcome

 

I don't suspect new pump cuz, read on line its a fuel pressure regulator symptom.

Original concern was low pressure, hard starting.

 

Sorry for the double post, there must be something going on with the vBulletin software. Anyway, the fuel pressure should be 60-66 psi with key on, engine off. It should then drop some with engine running and jump back up in reaction to the drop in manifold vacuum when you hit the accelerator. So, it's probably the fuel pressure regulator like you suspect but you mechanic may be avoiding that diagnosis since it's not easily accessible. You know, what happens if it isn't after all that?

 

No I don't know, What happens if it isn't after all that?

 

Well, he'd have one heck of an irate customer on hand, is what I meant.

 

Ah, I missed the "pinched return line" part. I think I have to agree with the mechanic. I don't know what brand of fuel pump your have but most aftermarket pumps are pure junk. Either that or the pump's not getting sufficient voltage and current.