Fuel smell upon starting

[Jeepmedic46]

There is a strong fuel smell upon starting my 2000 XJ. Jeep has the 4.0 engine. It is a replacement engine put in by the previous owner. Also the gas mileage is terrible. I go down the street and I use about a quarter of a tank. Thank you, new to all this and looking for places to start looking.

 

[RCP Phx]

Crawl under/over your vehicle right after staring it and look,smell , and feel for leaks. With the exception of corroded lines there are not to many places fuel could be coming from.

 

[Evan03]

Most likely leaking on line supplying fuel to injectors at the front of the motor.

 

[Skwerly]

Crawl under/over your vehicle right after staring it and look,smell , and feel for leaks. With the exception of corroded lines there are not to many places fuel could be coming from.

Also in the engine bay. That's a scary place to be squirting raw fuel.

 

[techno1154]

Or maybe you are in cold weather so the cold start device is adding extra fuel to keep the engine running until it warm up enough.

The above posts have some great advice. A once over visual is needed regardless. I do that to my XJ regularly both in the engine compartment and under the vehicle with the engine running.

 

[Ivan]

The Charcoal Emission canister located by the left rear wheel well, has been a source for fuel leaks / smells in the past.....

Follow your fuel lines there...you should be able to find it behind a cover...

 

[Jeepmedic46]

Not finding any leaks, fuel smell only seems to be when the Jeep is cold. Does get horrible mileage. Getting 4 miles to the gallon. I will check the canister. Could it be a clogged injector? Will double check what people have said above.

 

[Black1990jeep]

Rich operation will kill the catalyst, 4 mpg is very rich if indeed that extra fuel is being sent into the motor.

On my jeep, the fuel pressure regulator leaked.

Avoid driving until fixed, you may have a fire hazard, of may end up killing the catalyst.

 

[Jeepmedic46]

Taking everyone’s advice and not driving the Jeep.

 

[lazyxj]

I would use a fuel pressure gauge to monitor the pressure and see if there is a leak, If so, without starting the engine, have a helper cycle the ignition key occasionally to build fuel and maintain fuel pressure, while you examine the fuel system from the tank up to the injectors. Wiggle the fuel line at any spot you can, looking for tiny seeps or drops of fuel. Not having the engine running reduces the chance of fire and the lack of heat and blowing air makes finding the leak easier.
If you smell it, there is a leak somewhere.

 

[Skwerly]

Yeah, 4 MPG is bad for a built big block V8. I sure hope you find the issue soon. What a bummer.

 

[Jeepmedic46]

Yeah, 4 MPG is bad for a built big block V8. I sure hope you find the issue soon. What a bummer.

Worse considering it’s a stock 4.0. I had a 86 with a built 302 and ran 33s and got better mileage.

 

[Jeepmedic46]

I checked out the fuel lines and found no leaks. Engine seemed to be running rich. I changed the plugs and found 3 of them with the bottom of the plugs smashed. Thinking the other owner put them in to tightly. Engine seems to be running better and no fuel smell.

 

[Anak]

Glad you found it.

Surprised you didn't have codes for at least misfires.

 

[Evan03]

If they're installed to tight the contact contacts the piston and smashes the spark plug gap closed or tighter then 035 and grounds out on piston creating a misfire condition that is unrecognized by the human while seated in the drivers seat..

 

[RCP Phx]

If they're installed to tight the contact contacts the piston and smashes the spark plug gap closed or tighter then 035 and grounds out on piston creating a misfire condition that is unrecognized by the human while seated in the drivers seat..

That's basically impossible in a 4.0 head unless you have installed incorrect length plugs(by quite a bit). Maybe if you had some kind of a "domed" piston but........

 

[Skwerly]

Whew! One less thing to worry about.

 

[Evan03]

Haha

 

[Jeepmedic46]

Definitely one less thing to worry about. I know I’m not going to get great mileage until I change gears. Saving up for those. Thinking of a Dana 44 up front and a 9” rear end. Thinking 4.56 gears. Would these gears and axles be to much for the Cherokee?

 

[RCP Phx]

Definitely one less thing to worry about. I know I’m not going to get great mileage until I change gears. Saving up for those. Thinking of a Dana 44 up front and a 9” rear end. Thinking 4.56 gears. Would these gears and axles be to much for the Cherokee?

It would depend on your desired goals. Those would be the ultimate axles but require deep pockets and/or fab work.