Fuel pressure problems

buick
gasoline

#1

I have a 1993 Buick Century with 186,000 miles. It has performed well and been well maintained. Recently it started to act like it was running out of gas, coughed, backfired and wouldn?t pull the hill I was on. It eventually died and wouldn?t start until after it was home. Since then, it starts and runs, but I am not confident in taking it back out.



I took a fuel line pressure reading, and it read 30#. The specs call for 40 ? 43#.



I have changed the fuel filter, fuel pump, and injectors, blown out the fuel line and checked the fuel regulator. The fuel pressure at the Schrader valve still holds at 30#, but the pressure from the tank to the gauge (dead ended) shows 43#



The fuel pressure readings are the same whether it is a static test or running.



Although the check engine light did not come on, I checked for any codes, and found nothing.



I have been told it could be the computer (ECM), but I am running out of money to fix the old doll.



Any ideas out there?


#2

The problem might be in the fuel pressure regulator. These can fail where they stick and no longer regulate the fuel pressure. With the engine running and the fuel pressure gauge attached, remove the vacuum hose from the regulator. This should cause the fuel pressure to increase. If it doesn’t increase, the regulator is defective.

Tester


#3

Have you checked anything other than fuel pressure, ignition system, compression, timing? If you have a new pump and filter and your readings have not changed it is not your problem, move on.


#4

Already tried that… with the gauge attached and engine running the fuel pressure reads 30#. Disconnecting the vacuum hose jumps it up to about 35#.

The pressure is 30# with the engine running or just pressurized by the pump.


#5

I am no mechanic, but I have worked on my cars for many years (too cheap to pay someone) Wouldn’t bad timing or low compression cause the car to run terrible? It will start and runs OK, but it still has only 30# pressure.
Do the injectors get their marching orders from the computer even if the engine is not running/