I have a 1992 Buick Century with a 3.3L V6. I noticed a hissing sound under the hood with the motor running. The short vacuum hose (about 2 inches) connected at the fuel pressure regulator was loose and leaking. I shut the engine, remove the end of the hose and alittle gas (about a teaspoon) came out of the vacuum pipe for awhile and then it stopped. I tightened (but did not overtighten) the end of the hose with a nylon wire tie. There was no existing clamp on it. The vacuum leak stopped (no more hissing). Now, the car is sometimes hard to start or restart. Do I have a serious problem? Did I do the right thing? Could this be caused by a clogged fuel filter? (it was changed 42000 miles ago).
Replacing the vacuum hose was the right thing to do. I do not know the manual recommended interval for a fuel filter on your car, so if you could check the manual, and also note the mileage of the car and other recommended maintenance in the manual, vs what you have done, that would be helpful. Sure it seems like some work, but it will help the quality of the answers you receive.
You need a new fuel pressure regulator. The only thing in that vacuum hose should be vaccuum. The diaphragm inside of the regulator broke. The vacuum is now sucking in fuel & flooding the engine.
It should be fairly inexpensive and easy to replace. If you do it yourself - relieve the fuel system pressure before proceeding!
Not that he needs it but I second cigroller’s advice. In fact, whenever I suspect a leaking fuel pressure regulator as the cause of a flooding condition, I pull the vacuum hose to see if fuel is present. If it is, I’ve found a bad regulator. The vacuum hose was loose and leaking because gasoline degraded the rubber hose, swelled it and made it deteriorate and leak. A sound vacuum hose does not need a clamp or tie to secure it.
Cigroller is right. If gas is present in the vacuum line then gas is being sucked into the intake. This will result in hard starting or restarting. It will also kill your gas mileage.
Thank you very much, all of you! If I decide to replace it myself, can anyone tell me how to relieve the pressure in the system?
There are a couple of methods. The most straightforward is probably to just find the fuse for the fuel pump (probably in the under hood box), pull it and start the car. It will quickly die, of course. Then just to be sure, find the fuel pressure test port on the fuel rail. Its a schrader valve - looks pretty much like the valve stems on your tires. Wrap a rag around it and pop the center pin with a screwdriver or something. You can also just go straight to the valve like this, but then it can still have anything from 30-60 lbs of pressure behind it and when it releases it shoots gasoline.
Of course, if you let it sit overnight there’s a good chance the pressure has bled off anyway.