Pontiac Grand Prix Forums : Grandprix

im going to be getting my hands on a fuel pressure tester to help diagnose the hard cold start on my GS, but i need to know what i am looking for when testing some different things.... on the list of possible culprits are Fuel pressure regulator, leaking injector (though i dont seem to have a misfire condition after changing plugs/wires, but further test driving required to verify) or weak fuel pump check valve. I am assuming that testing the fuel pump check valve is relatively easy, involving having the gauge hooked up to measure weather or not the pressure drop is within the specified range after sitting for x number of hours. what's the range this should be? if that checks out, what do i need to watch for/how do i test the other items?

I know you can check the regulator by having the gauge hooked up, and car running and just pull the vacuum line off the regulator, and pressure should rise(no vacuum= WOT=higher reqired fuel pressure)

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2002 GT...Wizardair, ZZP 2.5 o/r dp, Special Eddition two-tone leather interior added, HUD added, 12" Brake Upgrade,strut tower bars, gmpp sway bars, poly motor mounts, -6an braided SS fuel hoses , Hptuned, Headers, Top Swaped.....
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Also pull the vac line off of the regulator with the car running and if fuel comes out of the vac port the regulator is shot.

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Red 2dr 99 GTP "Old setup" Z7 t66, A/A IC'd, Custom Heads, 65# Inj, ST2 Cam, Meziere Elec Pump, JP Double Roller(with machined crank gear), Plogs, PLX W/B, Powrtuner

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