Fuel Pressure Regulator Leaking Fuel

Discussion in 'SN95 V6 Mustang Tech' started by Buttaz, Aug 16, 2007.

  1. Ok, so I searched around the forums and I couldn't find anything that helped, so here's my issue. . .

    I just recently rebuild my 1996 3.8 v6 due to a blown head gasket, and got all the finishing touches done today. But when I was pulling into the shop to get my exhaust welded up again, the mechanic noticed a HUGE fuel leak coming from the engine bay. So we relieved the fuel pressure, doused the engine with water, and they did their business. After the exhaust job was done (headers to dual 14" glass packs ) I pulled it into the parking lot and popped the hood.

    It seems like the Fuel Pressure Regulator is leaking gas all over the engine. I unplugged the vacuum line and it is creating vacuum just fine. I removed it and the 2 o-rings look fine, so I tightened it back on only to have it just leak again. Oh, and it seems like that when the vacuum line is connected, and you shut off the car (and maybe when the car is running also, its hard to tell) that there is a hissing sound, kind of like a vacuum leak.

    If I was a rich man, I would just go buy a new $79 regulator from NAPA, but I've got about $40 in my pocket and i want to make sure thats what I need to do before I do it. thanks guys!
  2. no body posted on this yet...I have a similar problem...
  3. There are two probabilities for this. The first, a pressure regulator is governed internally by a rubber diaphragm and in time this weakens, so, have you done a fuel pressure test to see if what the output is? The second, when you remove a regulator it is very important to make certain that it is seated properly. The o rings being intact is good thing but if the regulator is not seated firmly, it will leak anyway. A trick I have used for seating fuel injectors and fuel rails after removal and repair is to take a rubber mallet and tap the rail where each injector is located. This will always ensure that they are seated, then I bolt down the rails. You can similarly, tap the regulator and seat it as well.

    This sounds like a case of it not being installed correctly. Recheck the o rings for cracks or poor/incorrect fit and then try seating. Also, check and make sure that the fuel is really coming from there and not somewhere else. Sometimes with leaks, the area you see the leak at is not necessarily where it is coming from.

    Something else I forgot to mention, when/if you remove the regulator, check to make sure there isn't some obstruction in the line where it connects, like another o ring that was forgotten.