Oldsmobile/Buick Repair: Buick Lesabre Fuel System, fuel pressure regulator, fuel pump relay

Question
Hello&Thank You    98 buick with 3800 v6 was very hard starting for a couple of weeks.after it has been sitting overnight i checked fuel pressure regulator no pressure present .after car is running it builds some pressure but after you turn it off it bleeds off. pulled vacumm line off while running fuel is present at the regulator. I Put a starter in it over the weekend and had the hot wire disconnected now it will hardly run at all .surges real bad and stalls immediatly after you take your foot off the gas .fuel odor is present all of a sudden and check engine light came on .sound like regulator is bad? thanks again.

Answer
Test the fuel pump for proper pressure and volume. Although it could be a pressure regulator, I have a suspicion that the check valve in the fuel pump is what is causing the fuel drain back problem and that the pump is also weak. Fuel pumps usually start getting weak after 60,000 miles.



Fuel pump operation is as follows:


1. The fuel pump runs for 2 seconds when you first turn ON the ignition switch to start the car and then it shuts off. This 2 second run period pressurizes the fuel rail to make the car start easier. This 2 second fuel pump is achieved via the FUEL PUMP RELAY.

However, AFTER the engine strts, this relay is BY_PASSED and the pump is run completly by the vehicles computer.


autohelp
autohelp