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Pulling my hair out over fuel vapor smell

krawler09

NAXJA Forum User
Location
Chattanooga TN.
Well first off I have a 95 XJ 4.0 and the p.o had replaced the motor with a 96. They used all the 96 fuel system parts including tank and sending unit (no smell with this setup). Well I found out the tank was rusted to hell and half full of water because the fuel gauge didn't work (was going to fix), so I started replacing fuel system parts to original 95 stuff (rail, injectors, sending unit, tank, fpr, filter and some lines). Ever since I have installed everything I have been getting a fuel vapor smell in the jeep. There are no leaks which I have checked several times. I have used a different tank and replaced the vapor canister and still get a smell but not as bad, I really smell it when I turn left and the gas goes to the filler side. Does any one know if there is supposed to be a good vaccume to the pressure relief valve lines at the tank or just a weak vac pull from the canister? Thanks in advance
 
'95 and "96 had many different parts, including the fuel rail, vapor cannister and its purge pump, and the '96 didn't have a fuel return line. '96 and up have internally reguluted fuel pressure (at the pump), and '95, I believe, still had the vacuum pressure regulator on the rail. You need to pick a year (the car is a '95, that would be a good start), and make all the parts match. The '96 injectors are different than the '95, so make sure they match. You probably couldn't have picked two years so close that are so different!
 
Thats what I was getting at I have already bought all 95 fuel system parts and had put them on. With having the 96 stuff it wasn't running to good I think it was mainly rigged to run and sell, because it was like this this when I bought it. It runs good now just has the vapor smell
 
Not sure if it has one. According to the evap sticker and the fsm the lines go from the tank to the canister and the main vac line from the can. goes to the intake and the top (small) vac line goes to the breather somewhere but mine doesn't have a place for it so I hooked up a vac line (not sure what it went to) from the firewall but it does't pull much vac. There is no pic of a purge pump on the sticker or fsm for the 95. This thing has been a headache since I bought it but I worked out the bugs except for this problem. I'd rather fight a missing problem than breath these fumes all the time.
 
The problem is you have the wrong air box lid. Get the right one for that year and the port for hose will be there. It's not a vaccum per say, it's real function is to recycle those fumes that you're referring too back into the into the intake.
 
I appreciate all the help, if I could afford it I'd take it somewhere. Can someone tell me if you take the hose off the fuel tank line of the canister if its pulling air? I'm not really sure how the evap canister works I haven't ever had to deal with it before.
 
There is a SOURCE vacuum line from the manifold (not the airbox) and the VENT line(s) from the tank. The source line goes to the cannister, the vent lines go to the tank. The fumes from the tank are pulled through the cannister and introduced into the intake manifold, where they get sucked in and burned up.

Have you looked at the injectors while the Jeep is running? They can leak only a tiny bit, run on to hot, warm engine and create a boat load of fumes. By the time you've turned the engine off and gone around to check for leaks, all the fuel has evaporated, no obvious leak.

There are really only a few ways you'll smell fumes. Bad cannister operation, disconnected vent lines, leaking fuel lines when running, bad fill hose or vent at the tank.

Since you're smelling it more when you're turning (and the fuel is moving around) I'd really be looking at the fill pipe and vent tube at the tank...seems a bit too obvious.
 
Yes I have checked the injectors and they are not leaking and there is no smell under the hood. All the lines are hooked up to the canister but I have no vac. pull at the vent line to the tank. I will check the fill and vent hose at the tank to be sure because that's where the smell seems to be coming from. Just didn't know if the canister wasn't pulling from the vent line if the fumes would build up and come from the fill and vent tube at the tank.

Evapcanoriface2.jpg


this is what i have, the one with the question mark should be connected to the intake also right?
 
The one you have labeled 'To Intake' should be connected to the airbox. The one you have labeled 'To ?' should be a vacuum line connected to the intake manifold.
 
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