Dang, she still stinks

[KeppelmanJ]

New thread here, old issue with volatiles in the '81 coupe trunk. I wrote that with soap bubbles I found a leak in the emissions manifold and fixed that. To experiment I reversed the check valve, drove the car, let it sit a couple days and switched it back. When I opened the connection the tank side inhaled audibly, deeply. So, I believe that means the system is leak proof from the gas cap, through the tank, and including all the hoses in the trunk on the tank side of the check valve since it maintained a good vacuum for all that time. Does that make sense? How's my logic here?
I also believe the trunk is sealed adequately. If you sniff in the trunk you can still smell raw gas. What's left is, as I see it, is that the rubber "multi-fuel" hoses I put from the tank to the manifold and to the check valve are not holding the gas. They're sweating. I have read that some of the new fuel blends will go through any hoses now, but I use only Chevron (except for the odd tank on an ALC reunion trip to CA) which I'm told is dino only with various octane additives. I don't know what to do except to drop the tank and replace the hoses again. What a discouraging thought.

[Charley]

Perhaps you are simply looking in the wrong place.The gas smell is originating from somewhere.It sounds like you have been pretty thorough with replacing and examining the rubber hoses.Are you positive your fuel tank or steel fuel tubing have no sneaky little pin hole leaks? Take some brake clean and spray down all the tubing real good and then blow it off good with compressed air.When you have everything absolutely dry and clean start the car and run it a while.Then check the fuel tubing from front to back with a good flashlight and look for any signs of wet spots.Also I would recheck the fuel tank(especially the sides and top) and the tank filler hose.

[KeppelmanJ]

Thanks, Charlie, for the pep talk. This task has gotten to me enough that I passed it to a good european auto mechanic. He retested the lines in the trunk today with 2.5 pounds of air and with soap solution found no verifiable leaksin either the emissions hoses or the filler piping. Still it smells in there. I believe the filler hose smells the stronger of the two so I am going to fab up an elbow from steel tubing and find some coupling rubber fuel pipe and have him install that next. I haven't really considered the engine compartment because the trunk smelled, but that would be next. The canister? Vapor hoses up there are new now.

[KeppelmanJ]

Charlie, I guess I didn't respond to your idea of a leak at the tank. First, the fact that the tank and connected hoses held a vacuum for 2 days makes me think the tank is ok - at least above the fuel level but that was pretty high. And...the trunk is quite well sealed with all the original rubber gasket material in place and looking good. And... the trunk smells with the car just sitting there. But sure, if all else fails it would be smart to empty the tank, lower it and do the soap test over the whole car. One thing that's nice about this mechanic fellow is that he loves driving the car. And what he works on mostly is BMWs, vintage and modern.

[Jim Keller]

I still suspect your suckin on exhaust, but, that being said.....

Are you installing fuel Injection hose, or normal fuel hose? that does in fact make a difference and could be a reason for the weeping I saw you describe earlier, normal fuel line is like for 3 to 9 PSI, FI hose is rated like around 40 plus PSI.....just a thought

[KeppelmanJ]

Thanks, Jim. I got the low pressure for the emissions trunk lines and the high for the tank to pump to filter, etc. I wish it were that obvious. This is really baffling. I determined that the fuel line is about 2" OD so I'll find so tubing of that size and form a 90 degree bend to copy the original, run that to the tank with new rubber bits. One less possible leak.

[Will]

Johnny, not to beat a dead horse but back to my original question: have you ABSOLUTELY ruled out the 3-way valve? Also, seperators can be culprits.

To test the lines you can use a trick we use to test for poopy hoses on boats: Clean rag with hot hot water, wrap around line. Wait. Unwrap and smell rag. The hot water makes any organic compounds flash off out of the hose material, into the rag.

[KeppelmanJ]

Will, I like your test method for rubber pipes. I'll try it. I'm still looking in the trunk where I definitely get smell but no leaks. As to the valve: it's a two way and we tried just putting a piece of tubing in place there, no resistance either way, and all seemed to work fine. The valve blows easy one way and harder the other. I guess Lancia wanted some slight pressure on the tank. I have a friend who just put a plastic fuel filter in place of the valve and that was fine. I wonder too about the charcoal canister. But I wonder, doesn't this system exit only to the intake? If so what difference would a saturated canister make? I can blow air (by mouth) forward from the trunk with little resistance.