Fuel smell in trunk (arrggghhh!!!)

[VeroTii]

I am hoping to get the experts to give me some ideas of what to check next.  I have a 74 tii and am getting fuel smell in the trunk.  Trunk only.  

Not in the engine bay or cabin (all lines have been rerouted under the car).  At this point I have replaced both gaskets and the filler boot. Also checked all the the fuel lines in the trunk and they are new and well clamped.  The vent line that normally goes to the canister is vented to the atmosphere via a hose through the body hole near the taillight.  The tank was replaced by the PO and looks clean inside and out.  I see no evidence of weeping fuel anywhere around the seams.  It smells whether I use the car or not.  What the heck is left?  Can anyone suggest a garage mechanic way to check for leaks in the system?  I am a fairly competent mechanical guy and this is driving me crazy.

[rjd2]

smoke test. positive charge the air cavity of the tank. you should see it visually if you have a leak.

[popovm]

6 minutes ago, rjd2 said:

smoke test. positive charge the air cavity of the tank. you should see it visually if you have a leak.

Time to pick up the habit again. The burning cherry adds to the excitement of the test. 
 

[Son of Marty]

Check your fuel filler boot the rubber bit between the fill port and tank for micro cracks paying the most attention to the inside of curve. 

[VeroTii]

Thanks.  I was just fishing for something typical of the 2002 like the flange at the right fender panel or something.  I have replace the filler boot with a new one so that is not the issue.  I don't have a smoke tester and am trying not to spend $100 for a  shop to do one so I think I will try soapy water and light pressure on the tank from the filler port.  Any other detection ideas are welcome.  Do they make a spray that changes color when in contact with gasoline?

[Hans]

Plastic sleeve on sender outlet pipe - check for cracks 

[tech71]

7 hours ago, VeroTii said:

 The tank was replaced by the PO and looks clean inside and out.  I see no evidence of weeping fuel anywhere around the seams.

Replaced with what? New tank? Used tank? I would not rule the tank out yet.

The seam you need to be checking is on the underside, thats where they like to rot.

You can get vapor leaking out with no outward signs wetness ect.

When you pressurize, spray around the upper seam so its wet, dont over pressurize!,

Maybe a couple PSI above ambient. Tank will need to be pretty much empty.

 

[Son of Marty]

Also check the o-ring for the fuel sender.

[jimk]

The flat gasket on the pickup on the Tii is a lousy seal plus when the tank is full to the top, gasoline is against the seal.  I smeared a Hylomar sealant on both sides of my flat gasket.  Gasoline doesn't affect Hylomar and stays gummy (non setting) and makes a vapor and liquid seal even when disturbed.

[Tommy]

I did a pressure test by pushing just a bit of pressure with air gun at the vent hole. It held the pressure overnight just fine. If it was leaking my plan was to spray soap water and find the leak.

Didn't hold the smell though. 😖 Eventually the smell atleast decreased when I replaced the filler neck with new one. I feel that it let the smell of todays ethanol fuel through as there wasn't any visible cracking. But if you have already replaced that maybe you can find a leak with pressure test.

[Mike Self]

I'm no tii expert, but the picture of your removed fuel pickup assembly (first picture) looks like someone really cranked down the screws that hold the pickup to the tank.  The metal around the screw holes is all distorted, as if there were countersunk screws used there.  One of you tii experts take a look at that flange; isn't it supposed to be flat around the screw holes?  

 

mike

[0257]

5 hours ago, Mike Self said:

I'm no tii expert, but the picture of your removed fuel pickup assembly (first picture) looks like someone really cranked down the screws that hold the pickup to the tank.  The metal around the screw holes is all distorted, as if there were countersunk screws used there.  One of you tii experts take a look at that flange; isn't it supposed to be flat around the screw holes?  

 

mike

Good observation and I think you’re right. Which just goes to show the lengths we’ll go to to kill that vapor leakage. As jimk suggests, the answer is still Hylomar.  I used it as he recommends, and I’m getting 0 fuel smell ever since.  Of course, be sure your vapor lines are intact and tightly connected, and that your vapor canister is not leaky. Or better yet, do as the Europeans and vent the vapor line directly out of the trunk through the existing hole in the trunk floor beneath and behind the filler neck. I drilled out a wine cork, ran the line through it, and plugged it into that hole.

[jgerock]

I think Mike Self may have gotten this one.   Please carefully flatten the suction device flange to get rid of those dimpled areas. I’ve attached one of my old pictures showing how the flange should look.

 

Good suggestion by Jim K. On the sealant.

 

I’d also replace the o ring for the sending unit. Use the same sealant or petroleum jelly on the new o ring.

 

BTW, tii’s don’t have the nylon spacer for the fuel line like carburetor cars do. 
 

(Former tii owner)

 

Jim

[VeroTii]

Excellent suggestions.  I keep suspecting the suction device since it is the biggest flange with lots of fasteners.  I will concentrate on that with a soap test.  Flattening those holes is also doable.  It does not have countersunk screws currently but who knows what was done previously.  I have never used hylomar but I will get some.  Thanks to all and I will report back on findings.

[jp5Touring]

This is something I need to do also.   Theres like twenty different Hylomar products.

What  specific one are people using or recommend ?    tia