Discussion
Hello everyone.... As we are all aware of the standard surgical tubing syndrome and the dredded fuel smell, I have replaced it but am experiencing a new fuel smell only under acceleration. This concerns me for obvious reasons but the cause is still yet unknown. My thinking here was an intake leak being forced out by the pressure of the turbo but I changed the plenum cover gasket and still have the smell. Two different occasions the rubber connector between the plenem and the charge cooler came loose on me but have since been tightened.
This remains a mystery.
SGB
This remains a mystery.
SGB
Actually if the canister gets saturated, if the purge valves are working correctly and the lines are not ruptured the fumes will be pulled into the intake manifold.
There are 2 purge or check valves that sometimes fail.
One is a circular disc looking valve at the front of the engine going to a fitting on the head. Normal engine vac will pull fuel fumes into the intake air. This valve is supposed to prevent the engine from blowing air/fuel mix back into the canister when a let up in engine vac occurs.
The other valve is the fresh air intake and also a one way check valve. You will find it mounted under the right hatch gutter. With the rear hatch open, just opposite of the right fuel filler you will see 2 screw heads on the right hatch gutter that most people wonder what they are for.
They screw into a bracket that hold the valve under the gutter. The only way to access this valve is to reach under the gutter with the carpeted tank cover off. This is also how one access the canister hoses that will eventually rot.
A common rookie mistake is to over fill or max fill the gas tanks then drive in a very robust manner. In an autocross or track situation, this has led to more than a few engine compartment fires as the canister fills to the brim with raw gas then is ignited. This usually leads to the loss of whole car. Recently a yellow V8 was on ebay burnt in rear. That is what happened at a track day in SF. Makes no difference if V8 or 4 cyl. If enough raw gas fills the canister your car will burn.
Calvin 90 SE
There are 2 purge or check valves that sometimes fail.
One is a circular disc looking valve at the front of the engine going to a fitting on the head. Normal engine vac will pull fuel fumes into the intake air. This valve is supposed to prevent the engine from blowing air/fuel mix back into the canister when a let up in engine vac occurs.
The other valve is the fresh air intake and also a one way check valve. You will find it mounted under the right hatch gutter. With the rear hatch open, just opposite of the right fuel filler you will see 2 screw heads on the right hatch gutter that most people wonder what they are for.
They screw into a bracket that hold the valve under the gutter. The only way to access this valve is to reach under the gutter with the carpeted tank cover off. This is also how one access the canister hoses that will eventually rot.
A common rookie mistake is to over fill or max fill the gas tanks then drive in a very robust manner. In an autocross or track situation, this has led to more than a few engine compartment fires as the canister fills to the brim with raw gas then is ignited. This usually leads to the loss of whole car. Recently a yellow V8 was on ebay burnt in rear. That is what happened at a track day in SF. Makes no difference if V8 or 4 cyl. If enough raw gas fills the canister your car will burn.
Calvin 90 SE
cnh1990 said:
The other valve is the fresh air intake and also a one way check valve. You will find it mounted under the right hatch gutter. With the rear hatch open, just opposite of the right fuel filler you will see 2 screw heads on the right hatch gutter that most people wonder what they are for.
They screw into a bracket that hold the valve under the gutter. The only way to access this valve is to reach under the gutter with the carpeted tank cover off. This is also how one access the canister hoses that will eventually rot.
Calvin 90 SE
Calvin,
Great info as usual! But, one correction, on the carburetted, US model 'G' cars, the two screw heads you describe in the hatch gutter hold the air filter for the air pump intake, assuming there are still some cars out there which have retained the air pump. BTW, Congratulations again on your trophy at Stone Arch Show! Happy Motoring! Jim'85TE
>> Edited by lotusguy on Thursday 19th June 16:46
cnh1990 said:
You are very correct about the air pump intake in G cars. I do not know much about the pre-Stevens cars as I would like. I must defer to your expertise on those models. Congrats on your 1st place at Stone Arch. Are you going to the hill climb at Afton?
Calvin 90 SE
Calvin,
Think we'll skip the hillclimb. Brenda and I are taking our nephews to the Back to the 50's carshow at the Fairgrounds this weekend. They're boasting 5,000 cars, and the kids love the Hot Rods...Jim
Once again I have to point out that I only smell gas under acceleration.
The hoses to the canister are in good condition.
The passenger side fuel tank has been changed and the driver side tank does not leak.
I'll probably change the canister and related hoses anyway and inspect check valves.
We'll see.
SGB
The hoses to the canister are in good condition.
The passenger side fuel tank has been changed and the driver side tank does not leak.
I'll probably change the canister and related hoses anyway and inspect check valves.
We'll see.
SGB
I recently purchased an 88' turbo. The fuel smell was thick and naturally the evap tubing was bad. I replaced it and like you I had a fuel smell under acceleration. Just cleaning one day, or like my car club buddies tease me - there was some tremmor in the Force- whatever, I took it upon myself to remove the fuel by pass valve, the hose leading down to the mixture crontrol unit, the hose leading upto the T joint at the charcole canister, and the hose leading up to the crank case breather valve. All of these hoses had a jelly like fuel substance collected in the lower areas. I have no idea as to why or what caused it... At any rate, I cleaned them all with silicon spray and a gun cleaning rod. The "acceleration fuel smell" is gone and has not returned.
These parts are very easy to get to and even if it does not solve your problem as it did for me, Hey, clean hoses!
These parts are very easy to get to and even if it does not solve your problem as it did for me, Hey, clean hoses!
windsorlotus said:
Once again I have to point out that I only smell gas under acceleration.
The hoses to the canister are in good condition.
The passenger side fuel tank has been changed and the driver side tank does not leak.
I'll probably change the canister and related hoses anyway and inspect check valves.
We'll see.
SGB
This is what I and several others have experienced. I only got mild, but detectable fuel smell during very high boost conditions, and though mild, it did force me to open a window or turn up the a/c fan to get some fresh air.
I also first began with the replacement of the balance line above the rear window between the tanks, but it was okay to begin with, though I replaced with 3/8 inch rubber fuel line.
So the problem was solved when replacing the one-way valve at the front of the engine which had failed (not one-way). Also, I recently found the rear one-way valve under the rear right corner of the chargecooler going into a "T" on the intake and the other side to the crankcase breather valve had failed. Though, I don't attribute that one to much fuel smell, I think it may have helped as well.
Special thanks to Calvin for his help on this subject!
- Mark91SE (no gas fume headaches at all)
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