Hey All,
This may seem a little lame but I'm trying to diagnose a persistent gas smell on my daughter's '98 4.0 Chero that is currently 5 hours away as she has driven it to college out of state. She mentioned a gas smell, not too strong, when she was home a couple months ago and I looked everywhere I knew to look and found nothing. No obvious puddling or even wet spots. She called today to say its getting worse.

I did an injector swap on this some time ago and would imagine that a bad O ring could be the problem (again no puddles or dampness and the o rings checked out OK going in). Any other ideas? Is there any kind of evaporator in the emissions that would cause this if a vacuum line were compromised?

She plans to drive it home next week so I can look at it properly but I want to be sure she's safe to drive home.

Thanks in advance!
S

 

O-rings can cause this. Injectors can also leak but it was a bigger problem on older jeeps.

 

There is an Evap canister on the passenger side of the engine compartment that catches gas vapor from the gas tank.

You can do the fuel rail pressure test for leaks. I forget what it exactly involves except for how much the pressure falls over time. I don't remember psi or the amount of time. I will look at the fsm I have and post it later. Edit: my fsm is for a 95 not 98.

Only other thing I can think of would be a cracked exhaust manifold/ leaking exhaust. Maybe yank the fuel rail an injectors out and redo everything.

 

On my 1993 JGC that I just bought for my daughter I had a fuel smell as well and thought it might be an injector. Turned out to be the o-ring inside of this vacuum pot on the fuel rail.

Miles

 

That is a fuel pressure regulator.

 

Which a 97+ doesn't have. It's in the tank.

 

96+ actually. I had that dumb thing leak on my 94. Won't have that return line either.

 

The one I was referring to was the photo from the '93 that was posted right above my last post. Sorry for any confusion.

 

I would ask her to run the jeep with the hood up and see if she can smell it over the engine (or hear a hiss etc). I had a persistent fuel injector leak that was hard to see since if the engine was warm, the fuel would be just a fine mist. Also, on a suburban I had, the fuel line had a pin-hole size leak that ejected a very fine mist that again could be detected by smell but was hard to see.

I'm betting injector O-rings.

 

I had a 96 that stank like gas too
found out the seam was rotted through on the gas tank

along with lots of other stuff

 

Thanks guys,
Fortunately I have a nephew who attends the same school. He has been garage trained since birth. I'll ask him to take a look before they hit the road.

I know there's a bit of an exhaust leak as I can hear it when it starts cold. Those rarely fix themselves.

I appreciate the input.

 

Probably not the issue, but I've that I had when I bought my heep was one of the return "fittings" (for lack of better word) in the top of the gas tank had melted due to a poorly pointed exhaust hack job. I'm really not sure what they are called, there are two of them on top of the tank, but I think they are party of the fuel return system, but it was letting fuel leak out on top of the tank and evaporating before it could start a puddle.

 

On my 00 I had a strong gas smell and the sending unit nut ontop of the gas tank had worked it's way loose and that was the cause for me

 

Found It!
After my daughter looked it over while running more than a few times. After my nephew looked at it. After my brother looked at it. She drove it home with no issues other than a gas smell once in a while.
I popped the hood, started it up and saw a few drops escape from where the fuel line goes into the rail.
Could it possibly be this simple? After several checks, no stains on the manifold...nothin. I replaced the fuel line and she drove it 5 hours back to school. No smell, no issues.
Thanks again

 

Glad to hear you fixed it