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Help! Noisy fuel pump and gas smell in cabin

COTallTodd

NAXJA Forum User
Location
Denver, CO
Have a '92 that has started to develop a noise in the fuel pump as well as a terrible fuel smell in the interior. I am going to replace pump, but any ideas why I'm getting the smell? It happens after I have driven it a little bit. Never right at first.
 
No way around it, you are going to have to crawl underneath the XJ with a good flashlight and follow the fuel in and return line all the way from the front to the back. Look really closely and feel for wet gas with your finger tips then your nose.

A common spot for a leak is the fuel filter, usually the rubber end connections.

Run your fingers around the lower edge of the plastic gas tank shield.

Fuel injectors sometimes drip on the outside. The fuel return line connection "O" rings sometimes leak.

If it is coming in the cabin it may be in the front someplace and the fumes are coming in the heater air inlet.

There is also a vent line all the way from the charcoal cannister to the fuel tank.

Not the kind of thing you want to ignore, engine fires are no fun at all.
 
What's really strange is that I can get in and drive for a good distance and shut it off with no problems....but once I start it back up to leave, I get the noise from fuel pump and the fuel smell
 
I don't think your FP is your problem, you're probably leaking somewhere on the outside (or a leaking injector) and the vent system is sucking the fuel vapor into the cab.

As 8mud said, get the flashlight out, and start tracing things... I know I've been on a kick about using fuel pressure testers (saved me a lot of headache in the last few days), but it's worth doing. Another possibility is if you have an exhaust leak (common in your year) and you're getting extra unburned fuel out the exhaust this can also cause it.

However here's what I would check in order from easiest to hardest:
1) Turn the vehicle on with the hood up, check the injectors, any leaking will be obvious.
2) With the vehicle still on, pull the vacuum connector to the fuel pressure regulator, see if there is any gas leaking out (again should be obvious)
3) while it's still on, look under the vehicle for any places where fuel is leaking
4) listen for any kind of exhaust leak

If you have a leaking injector, determine whether it's the seal or the injector, replace as necessary
If your FPR is leaking - replace
If you notice gas leaking out of the vehicle, try to determine where, the rubber hoses that provide both supply and return are prone to rotting with ethanol gas.
If you have an exhaust leak, check and see if the vehicle is running rich.

Also, there may be a defect in your vapor recovery system, check and see if you're getting fuel all the way up/into your charcoal canister, it's possible it is saturated with fuel, which may mean your engine isn't sucking the vapors out and burning them. This IIRC is controlled by the vacuum system which opens up a valve at the air box (this is what that really big tube that goes into the airbox is supposed to do, usually it mounts near the big rubber hose that connects the airbox to the engine.
 
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