Since toying with my fuel rail on the 3800 sc, I was re-routing my fuel lines, I might have "distrubed" my fuel regulator. My symptom is I have no fuel pressure when I shut off the car. It immediately drops to zero. I am almost 100% sure I dont have leaky injectors. I did take apart my regulator and possibly I either did not put it together right (assembles pretty easy) or it is old and just not functioning. From some reading online they are a common failure on the the 3800 engines. Anyone else have experience with these or their failure?

Use some soft jawed hose clamping pliers, pressure up the rail and clamp off the supply line at the hose section. If the pressure holds, the problem is not your regulator. Don't forget the check valve in the fuel pump outlet port could also be faulty. Double check the regulator diaphragm by pulling off the vacuum hose with the rail under pressure . . . you should NOT see fuel.

If your fuel pressure immediately returns to zero right after you turn off your engine its probably the FPR. Once they are pushed in place and the snap ring replaced there is not much you can do to install it wrong. If you decide to replace it MAKE SURE that you are buying the 2-BAR unit. It looks physically the same as the 1-BAR unit and don't buy one at Autozone or Parts America. Buy one from Rock Auto and make sure that you make the right selection. Last time I purchased one at Autozone they sold me the Standard Motor Parts 1-BAR unit for the 3800N/A engine. It was instazlled did not work correctly and ended up as a $55 mistake that they would not rectify. Had to buy the AC-Delco (Bosch) unit AC-DELCO Part # 2171422

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Is there any way to tell if the unit is defective? (I hate replacing a part that works fine.)

There is no fuel in the vacuum line and there are two rubber washers on it. If I can just replace the washers then it should work.

[This message has been edited by RotrexFiero (edited 11-14-2010).]