1997 Tahoe, 5.7 Vortec , 4x4 @70k miles.

loosing fuel pressure:

Removed intake manifold to replace fuel pressure regulator: Existing regulator has no vacuum line attached to nipple. Manual says it should have one. Don't see any possible routing for vac line if it is missing. Has it been removed? Any ideas?

Also replaced fuel pump and now it is noisy in fuel tank, (maybe too much fuel returning to tank since no vacuum to pressure regulator). Maybe burst return line on pump assembly in tank. Sounds like it is pumping air or high pressure fuel through burst line iin tank.

I'm not sure which manual you are utilizing.

The fuel pressure regulator, as you saw, does not have a vaccum line connected. So, what you found and put back together is correct.

I'm also not sure what you mean by "noise in the fuel tank". If you replaced the pump, filter (which you don't mention, but is "reguired" to have the warranty on the pump, and which I assumed you did) and pressure regulator, you might look at the ERC solenoid. Could this be causing the problem?

At least you've done all the hard work.

BTW, did you have any error codes before changing the fuel pressure regulator (most often you would have had one if the pump or regualtor needed replacing) and do you have any codes now?

I'm using a Chilton Manual, covers all trucks late 80's to 1998. After removing the manifold they say remove the vacuum line to the pressure regulator, maybe it's generic, one size fits all.


Photo attached:
Regulator nipple is facing up for camera only, should face down (Rotate 180 Degs)

To Date:

New Pressure Regulator
New Filter
New Fuel Pump Assembly (2)

I took the new pump out again and got another replacement from the parts store. Worked fine for a day or two, no noise. Now noisy again. Sounds like a gurgling sound, hard to explain.

Pump brand is Master ($215). Probability of 2 bad pumps is low. Plan to take it out again and buy one from the Dealer ($325) ? Third time lucky. Am getting good at dropping the fuel tank now.

No Trouble codes ever. Hard starting initially after standing for 1- 2 days, fuel pressure drop. Now starts every time.

Not familiar with ERC Solenoid. Will research.


Thanks