fuel problem help

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May 4, 2006 | 12:27 AM

antoine

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Senior Member

Joined: Mar 2003

Posts: 851

Likes: 3

From: vacaville,ca

Car: 1988 camaro z28,1997 camaro lt1

Engine: 355 afr 195 heads,tpis big mouth

Transmission: 700r-4 built by me 3-4 z pack

Axle/Gears: 3.42

fuel problem help

I have a 1988 camaro supercharged 30 pound injectors 6:1 fmu 255 walbro pump i am having a 3/4 throttle ping so i put a fuel gauge to check pressure went on the freeway and at 60 mph fuel psi was 35 and at full throttle fuel jumped to 45psi,i`am using a fmu so my fuel psi should be over 60psi right not 45psi.

May 4, 2006 | 01:47 AM

rocluvr0013

Senior Member

Joined: Sep 2004

Posts: 765

Likes: 1

From: Chico/Antioch California

Car: 1989 iroc Z Hardtop

Engine: 350 tpi

Transmission: 700r4

45 psi is right around stock

May 4, 2006 | 01:54 AM

ttypecamaro

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Joined: May 2005

Posts: 841

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From: Baltimore, MD

Car: 09 Cobalt SS Sedan. 92 Z28 vert

Engine: 2.0T EFR6758; 5.0TT T3/T4 8psi

Transmission: F40; 700r4

Axle/Gears: 3.76 LSD; 3.23 posi

35psi is about stock for closed throttle(idle vacuum) and 45 psi is around stock for WOT. The fmu only increases pressure when in boost, where you in boost? do you have a booster pump? usually people use an inline booster pump to aid the high commanded fuel pressures by the fmu. my guesses are that your pump can't do that pressure anymore or the boost reference blew off your fmu.