Fuel pressure failure

[Hib Halverson]

Hi there vette lovers..I´m having some trouble with my 90 Zr1. My fuel pressure drops just after my engine fires up, and the engine stalls. Seems maybe like a fuel pump problem, but this symptom only occurs after engine is hot.

Run the fuel pressure tests in the service manual paying close attention to the insructions on how to isolate each pump for testing.

My guess is the primary pump has failed. That scenario almost always matches those symptoms.

The engine starts and runs until coolant temp rises on both pumps then the ECM shuts off the secondary. Obviously, when that happens, if the primary is not running or is operating improperly, the engine may quit.

Talking w/ vette mechanic, I was told that the pump is welded to the assembly and re-attaching a new pump to the assembly is impossible.
(snip)

Sheesh....another case of a Vette mechanic who's really not. LT5 fuel pumps can be replaced. You can buy the pumps from several sources such as Airtex and Warner ( the Warner number is P36). The only slightly dfficult part is the replacment may require some soldering of wires in the pump/pick-up assy.

 

[rkreigh]

I just saw a post from MOM (Dave Bright) that the BB Suburban Fuel pumps are a direct replacement. I haven't had a failure yet so I haven't tried them. I'd be tempted to see if a Walbro 340 pump would fit. they flow well and are just over 120.

the pumps can be replaced. the dealer sells you the WHOLE assembly at a huge markup!!!

don't buy it. fix the bad pumps. I would replace em both while you have the fixture out.

anyone ever upgrade the ZR1 pumps to a different unit???

on the turbo buicks we use twin walbro "XP" pumps (modified 340) and they flow enough for over 800 ponies!!!

IMHO, the two stock ZR1 pumps are enough to feed 600+ HP. very nice fueling system.