Strong fuel smell. Cap filler area.

[JIMJAM]

Long time issue Ive had but a friend today freaked out after I filled up at how strong it was. I guess Ive gotten use to the smell. After filling up "not overfilled" or if I nail the brakes with 1/2 tank or more, I am getting a strong gas smell.
I have taken all the panels in the trunk off a dozen times and ruled out anything with the fuel pump/boot area. The smell is strongest right at the cap area. Ive tightened every camp I could get a screwdriver on. We rocked the car and my friend is convinced its the cap venting. Which btw was bought from DMC 2 years ago.
I do not think its the cap venting but its either that or something very close maybe even underneath it. I cannot see any wetness.
Any ideas on how to finally solve this for once and for all? The cap looks very cheaply made imo. I remember trying years ago without any luck 3 local bought caps and finally buying the DMC one which feels like its snug.
Even now after filling up 3 hours ago the smell of gas in the garage is very noticable so its something I need to resolve.
Thanks ahead of time.

[JIMJAM]

I stand corrected.

I placed chocks in front of the wheels and rocked the snot out of the car. The gas is leaking from around the sending unit. Ive triple checked this before. Clean threads,no dirt ect. Tighten down...... Still its leaking

Time to burn off some fuel and take it out "again" and see whats going on.

[jmpdmc]

Which fuel sender do you have and has it ever been removed? I have a DMCH unit from about 2004 that, when I removed it once, would not re-tighten. The gasket swelled with fuel exposure and I had to call them for a new gasket, which they sent at no charge. I have not removed the sender since. Maybe this is your problem.



Jeff

[JIMJAM]

I think everything on the car that fuel touches has been replaced. That said I cannot remember if that gasket was replaced. I have had the sender out many times trying to get the sender to operate more reliably. I now go by mileage and the gas gauge is really just for looks so once I get that sucker sealed I do not plan on opening it ever again. But you are right in that even when you tighten it down I never really felt 100% about the seal.
Going to take a better look in the light later and maybe place a order if need be. Thanks for the reply.

[Bitsyncmaster]

Put some grease ont the threads. Those plastic parts can bind up and you never get it screwed down.

[DMC3165]

I'll jump in on this because I had the same problem for several years. If you are running a stock setup your problem is in the evaprative system ie the charcoal canister in the back. Check to make sure none of the ports on the canister are clogged (or the canister itself is not clogged) and all the vacum lines are connected to engine vacum and not rotted. It's also a good idea to replace your rollover valve near the fuel cap or bypass it with a brass union because it's completely useless anyway. It took me forever to figure this out but mine got serious when my tank was over pressurizing causing the fuel boot to pop off the tank repeatedly with a loud thud every time it did it. In my case the port on the canister was clogged preventing the fuel vapors from going into the canister. After I freed it up I found the vacum line to the engine had a split in it also. Before I got to this point I bypassed the rollover valve but that did nothing because it wasn't the problem.

This is probably the most over looked area on a DeLorean. The boot is the weakest link in the chain so if anything is wrong that's where your vapors are coming from. The second spot is fuel cap but the port that feeds back to the charcoal canister is directly below the filler cap. So if everything is working the hot vapors should be drawn back into the canister. I found out the valves on the canister will get gummed up over time and stick especially if the car sat around for a while. My canister was original until I replaced it in 2012.

Try this, take your car out for a long drive and get evrything nice and hot. When you get back open the filler cap with the engine running. If you have excess pressure under the cap and hot vapors bellowing out the filler you've got a problem in the emmission control system and odds are it's the canister. You could also just pull the canister and see if the ports are clogged but it's a real pain to get that stupid thing out.

I replaced everything in mine and no more smell at all! took me 2 years to figure it out!

Also the car idles much better after i replaced all this stuff too. No more hunting or any other problems.

[JIMJAM]

Great info above. Thanks!
As we all know with this car anything is possible including multiple issues at once but the fuel leaking around the sender is blaringly obvious. I have tightened that thing down many times and snug so the rubber seal not be working. And or the threads are damaged from strong arming it. Never personally opened up the rear charcoal area but I can assure you its been looked at by others. All the fuel lines,vac hoses ect are all new. Still I am curious and maybe take a peak but "If it aint broke ,Dont fix it" has been ingrained into my head. That and "Have you cleaned your grounds?". HAHAHAAHA

Hey Dave long time no see. So whats the latest greatest gadgets you got for the D? I never solved my intermitant dead ignition switch. I am supposed to go visit Ron and let him have a crack at it.