Skip the auto shop - Our mechanics make house calls

Q: fuel pressure leak?

asked by on

boy do I have a headache of a problem.I have a 1993 jeep grand Cherokee.Runs great but developed a fuel leak in back by fuel pump.Replaced the lines.Starts and runs fine for about two minutes then pressure seems to build and fuel pours out over the top of the fuel tank.Its very difficult to pinpoint exactly where it comes from,but it seems like some kind of back pressure is causing it to leak somewhere above the tank.Any hints?Thanks so much ahead of time.You help us all out so much.Been reading the posts,and just joined the community.

My car has 200000 miles.
My car has an automatic transmission.

A: Hi there, and thanks for writing in. Than...

Hi there, and thanks for writing in.

Thank you for all the kind words as well, it means a lot. As for your car, you have a send line and a return line. You'll need to verify fuel is coming through the return line. If not, you could have a restriction in the return line or a bad fuel pressure regulator. If you haven't done so already, change the fuel filter. For starters I recommend getting a fuel pressure test gauge to verify a pressure build-up.

A restriction could be a kinked line, a poorly flared connection, or debris in the line. A visual inspection of the lines and flares at the connection points is required. Then with the line disconnected, compressed air should verify there is not any debris in the line blocking the flow. To test the fuel pressure regulator with the fuel pressure gauge attached, disconnect the vacuum line attached to it, and the pressure should read higher or change, then reattach the vacuum line and the pressure should drop or change. If not, you have a bad regulator (that is after verifying the return lines are not restricted).

If you do not have a restriction or pressure buildup, you unfortunately may have to lower the tank to get a good visual inspection of what is actually leaking. If you want to have the fuel leak diagnosed, you can contact a professional technician, such as one available from YourMechanic who will perform the diagnostic and provide an appropriate repair solution.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: Van running rough; fuel flow problem

Hello. The 4.3 liter engine in your van has quite a few common problems. If it feels like it is starving for fuel, it may simply be a clogged fuel filter. It may also have worn out spark plugs or...

Q: Car will not start

Hello. It sounds like the battery died while you were driving. This will occur if there is a bad battery terminal or it may be caused by a bad alternator. If the alternator was not charging the battery then the...

Q: Need to no how to bypass lamp failure sensor for tail & brake lights to work

Hello. Bypassing the lamp failure sensor involves locating the correct signal and ground wires and splicing them together to bypass the circuit. The actual cutting and splicing process is rather simple, however, you must make sure that the correct wires...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
How to Renew Your Car Registration in Oklahoma(DELETED)
Having your car registered with the Oklahoma Tax Commission is an important part of driving legally in this state. You will need to do this within 30 days of moving to Oklahoma...