Fuel Smell Intermittently, EVAP System Operation
#1
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Fuel Smell Intermittently, EVAP System Operation
On a 1990 XJ six cylinder Renix I once and a while get a whiff of gas smell, smell it when working under jeep. jeep has not been driven for five weeks. I suspect the smell happens do to the EVAP system charcoal can, or its hoses or?
I have the factory service manual, but it is not detailed on the EVAP system.
my charcoal can has two hoses up top, one to the air intake boot, the other goes back to the gas tank. On the bottom of the charcoal can is drain hose that is open on the end facing down at the road.
The smell seems to burp every now and then, it is a fleeting smell
At the gas tank At the vent hose is there supposed to be any valve, check valve, a roll over valve or such, or does it free vent to the top of tank?
What might cause my charocal can to become smelly? to burp (the burps might corrolate to the temperature warming at mid day)
What is the purpose of the drain tube on bottom of the charcoal can?
PS, I wheel at sometimes extreme angles, and have over filled tank many times to squeeze extra range in. Could either have flooded the charcoal can?
Thanks!
I have the factory service manual, but it is not detailed on the EVAP system.
my charcoal can has two hoses up top, one to the air intake boot, the other goes back to the gas tank. On the bottom of the charcoal can is drain hose that is open on the end facing down at the road.
The smell seems to burp every now and then, it is a fleeting smell
At the gas tank At the vent hose is there supposed to be any valve, check valve, a roll over valve or such, or does it free vent to the top of tank?
What might cause my charocal can to become smelly? to burp (the burps might corrolate to the temperature warming at mid day)
What is the purpose of the drain tube on bottom of the charcoal can?
PS, I wheel at sometimes extreme angles, and have over filled tank many times to squeeze extra range in. Could either have flooded the charcoal can?
Thanks!
#2
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Year: 1989
Model: Comanche (MJ)
Engine: 4.0
Any of the injectors wet on the outside right after you shutdown the engine? My intermittent whiff of gas turned out to be one of the metal injector housings starting to rust through. Had to look right after running as it would evaporate pretty quick.
#3
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Year: 1988
Model: Cherokee (XJ)
Engine: 4.0L
I replied in the "other" forum. Rather than link, here's "copy/paste"
It's not a drain, it's a fresh air inlet. The FSM is not very detailed because the evap system is pretty simple.
There's a venturi in the air cleaner tube that creates a small vacuum. This draws the vapors from the canister when the engine is running. The other port on the canister is a metered orifice that connects to the fuel tank, the source of the vapors. The bottom vent allows fresh air to be drawn in and mixed the the fuel vapors. Ultimately, it's all drawn into the engine for combustion.
So check for any cracks in the canister, the lines from the tank and to the air cleaner. Pull the air cleaner tube (snorkel) off and check the venturi. It's certainly possible that extreme angles and overfilling could back some extra fuel up the lines. This could make the fumes escape the canister if it sits for a few weeks. After all, the canister is pretty old.
Your '90 should have a rollover/relief valve but I don't think it's connected to the evap.
It's not a drain, it's a fresh air inlet. The FSM is not very detailed because the evap system is pretty simple.
There's a venturi in the air cleaner tube that creates a small vacuum. This draws the vapors from the canister when the engine is running. The other port on the canister is a metered orifice that connects to the fuel tank, the source of the vapors. The bottom vent allows fresh air to be drawn in and mixed the the fuel vapors. Ultimately, it's all drawn into the engine for combustion.
So check for any cracks in the canister, the lines from the tank and to the air cleaner. Pull the air cleaner tube (snorkel) off and check the venturi. It's certainly possible that extreme angles and overfilling could back some extra fuel up the lines. This could make the fumes escape the canister if it sits for a few weeks. After all, the canister is pretty old.
Your '90 should have a rollover/relief valve but I don't think it's connected to the evap.
#4
CF Veteran
Thread Starter
I replied in the "other" forum. Rather than link, here's "copy/paste"
It's not a drain, it's a fresh air inlet. The FSM is not very detailed because the evap system is pretty simple.
There's a venturi in the air cleaner tube that creates a small vacuum. This draws the vapors from the canister when the engine is running. The other port on the canister is a metered orifice that connects to the fuel tank, the source of the vapors. The bottom vent allows fresh air to be drawn in and mixed the the fuel vapors. Ultimately, it's all drawn into the engine for combustion.
So check for any cracks in the canister, the lines from the tank and to the air cleaner. Pull the air cleaner tube (snorkel) off and check the venturi. It's certainly possible that extreme angles and overfilling could back some extra fuel up the lines. This could make the fumes escape the canister if it sits for a few weeks. After all, the canister is pretty old.
Your '90 should have a rollover/relief valve but I don't think it's connected to the evap.
It's not a drain, it's a fresh air inlet. The FSM is not very detailed because the evap system is pretty simple.
There's a venturi in the air cleaner tube that creates a small vacuum. This draws the vapors from the canister when the engine is running. The other port on the canister is a metered orifice that connects to the fuel tank, the source of the vapors. The bottom vent allows fresh air to be drawn in and mixed the the fuel vapors. Ultimately, it's all drawn into the engine for combustion.
So check for any cracks in the canister, the lines from the tank and to the air cleaner. Pull the air cleaner tube (snorkel) off and check the venturi. It's certainly possible that extreme angles and overfilling could back some extra fuel up the lines. This could make the fumes escape the canister if it sits for a few weeks. After all, the canister is pretty old.
Your '90 should have a rollover/relief valve but I don't think it's connected to the evap.
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