What are the symptoms of a faulty fuel pressure regulator?

Answer 1

* Black soot on spark plugs * Black smoke coming from tail pipe * Rough running * Fuel in oil, smell the oil dipstick * Stalling * Raw gasoline coming out of tail pipe

To verify: remove the vacuum hose from the FPR while the vehicle is turned off, if there is fuel in it the FPR is bad. If you turn the key to the 'ON' position DO NOT TURN OVER and fuel comes out of the vacuum hose the FPR is bad. It is possible for the fuel pump regulator to be bad without fuel coming out of the vacuum hose. You can also test the fuel pressure.

These are the things that I have found in my research. I am not a mechanic, there may be other symptoms of which I am not aware. Equally these tests may also point in another direction at times and there may be other ways to test that I am not aware of. Always consult with your mechanic and keep a fire extinguisher handy when ever you are dealing with gasoline or other flamable liquids. FYI:

The regulator attaches to end of fuel rail. If you have an OBD II Vehicle, you should be seeing a CEL if anything goes wrong with fuel system. Fuel Injectors:

It seems older cars have fuel injector issues much of the time due to the technology not being so great on single pintle injectors and years of carbon build-up.

Also, fuel may leak through regulator into vacuum line that is attached. These rarely go bad, but you just never know. My first guess would be to disconnect fuel injectors and listen to engine performance. If you disconnect one and it has no difference on idle, you have found a dead injector and/or plugged injector. You can also do an Ohms test if you have access to the injector pins. You are looking for an INFINITE value of resistance, meaning the injector is NOT FIRING.