Hello!

Ran into a new problem, a fuel leak by the fuel gauge sending unit that was not there last week. It's a very very slow 'weeping' leak that looks like its coming from the riveted housing that secures the sending unit. I replaced the sending unit a couple of months ago. Questions I have are:

1. Can this be due to heat? It has been exceptionally hot here lately.
2. Is there a way to tell if the leak is at the riveted housing or due to the sending unit gasket?
3. I've turned the ignition (not engine) on many, many times lately as I troubleshoot a brake issue that is driving me to insanity. As the fuel pump kicks on every time, can this cause pressure to buildup in any part of the system?
4. The strange tone is potentially unrelated but I hear a very high frequency/pitch noise coming from the trunk area even with the battery disconnect switch off. I left the disconnect switch in the on position and after two days my battery was at 4.5V. I've been unable to locate the noise as it is very faint. I promise this is not brake issue induced insanity and its real!

Here are pics of the leak taken ~40seconds apart:




Thanks!

 

My first thoughts with only 1 C Club down.

That fuel weep is more than likely the actual sender gasket/seal.

OR

The face of the sender, and tank that the seal sits against has a score/scratch/whatever, thus giving a path for fuel to escape.

The riveted item, NAH, never had one of them go AWOL
The white plastic insulators that the terminals are part of, MAYBE, bit of a stretch.

The only thing pressurized with the key movement os the fuel hose FROM the pump outlet TO the outside world, AKA, the engine bay.
The supply side of that pump is purely good old gravity.

That humiing is possibly the electric antenna having a Blonde moment. GREEN relay near the tail light, inside the boot is most likely culprit.

 

Maaaaan! I LOVE your posts! Don't EVER stop 😊

Does it smell like gas,,, or could it be condensation? Gas has this amazing quality to be or seem colder than I ever expect it to be compared to the world around it... If it's been hot, the difference in temp between the atmosphere and the temp of the face of that cover (due to the fuel behind it) may be causing condensation...? Maybe?

 

Thanks! I will remove the sender unit and check/renew the seal, I'm glad to hear that is the most likely culprit. Though, I'm not sure why it would start after a couple months, stranger things have happened. It's definitely gas as well sadly.

The noise is more of a tone rather than a hum. The aerial is currently sitting in the trunk awaiting some lube on the motor. Is the green relay for the aerial? Because it happens with the battery off it might be the disconnect switch?

I think I will need to stick my head in there when the car is off ramps and see if I can pick it up. Could also be nothing, and the battery drain is caused by something else.

 

Is the noise the fuel pump or the filter which might be a tad blocked?
If the riveted ring has failed, or even if you want to fix it anyway to be sure, buy some top notch G Flex epoxy; remove the sender, epoxy the join you will be able to feel inside, using a gloved finger. Let it go off. Epoxy again to be sure.
Refit sender, job done.

 

It is hard to locate the sound as the rear is on ramps currently, but my closest guess is that it is from the pump/filter. Would that have the possible to emit such a noise with the battery disconnected?

Excellent suggestion on the epoxy. I will do that when I renew the sending unit gasket. Thanks!

 

No, not with the battery disconnected. You may well have a blocked tank breather and the noise was excess pressure escaping somehow. This would also account for the weeping rivetted ring.

 

The rubber gasket on my sump tank recently failed. Same type of arrangement as the sending unit. These are old cars now. The rubber wears out after awhile.
I suggest focusing on the simple before moving onto the harder fixes.

 

OK, the mud clears a tad, as does the head, coffee, luv it.

When you get that noise, simply remove the fuel filler cap. Greg is on the track for sure, as your market got so much venting, rebreathing stuff, that age is now against you.

If the noise stops, then venting/breathing is the issue.

With the battery disconnected, that car is deemed DEAD electrically.

I agree with Brad, SIMPLE cars, do not over think anything, it is counter productive, and wastes drinking time 100%.

 

Greg, you are as smart as you are handsome. I opened the fuel filler cap and a 3 second woosh of air came out. I closed it and came back an hour or so later (having never ran the car in between) and got a 2second woosh.

How does this even happen? Rust blocks these fuel breathers? I thought this car had 3 or 4 of them for the fuel tank. I've also had the rear wheels on ramps for the past couple of weeks. Would this have any effect or its just that time for something else to require maintenance?

 

Your car has a ludicrously complex tank breather system. If you look under the car, just in front of the LHS rear wheel, up on the inside of the chassis rail you will see a thin pipe emerging from the chassis. This will be connected to a rubber pipe that goes to the carbon canister at the front of the car that is eventually connected to the inlet manifold via all sorts of valves and bit.
If your laws allow, rip the entire lost out from the rubber pipe forward. This may let the tank breath. If not then up inside the RHS buttress there is an evap canister with three pipes going to it from the tank, and hidden behind it is a Rochester valve that may well be blocked. One or all of these items will account for your lack of tank venting.
Once you have identified all this, there are various solutions to simplify.
https://parts.jaguarlandroverclassic.../brand/jaguar/

 

Can the rubber pipe forward to the engine be removed and left that way? Or is the connection to the inlet manifold required and would need to be reworked to simplify this system?

 

see next reply from me.

 

Aussie fuel tank breathing,

Drill a 1/64" hole in the fuel cap, drink beer, SIMPLE cars, as I said before.

OK

If your car still needs to meet certain emission test standards, DO NOT do the Aussie fix.

 

If you mean related to the tank breather (sorry i misundertood your post in my last reply which was about the PCV system, my mistake) then everything can be removed from under the car forward, including the canister and all its pipes and rubbish, and just block off the place it goes into the inlet manifold.

 

Don't mean to hijack, but it's the same stuff.

So I have a 90... It's been a long long time since I've had my tank out... Mine is a convertible... Would I still have all this stashed away somewhere in my car?

I have done away with the canister in the LH front wheel well. And associated hoses to and from.

I have the 1/64ths hole in the cap, but still, occasionally, especially when it's hot, get fumes and gas smell inside of the car. Looks like I may need to go on the hunt, again...
I've never found this stuff. Maybe some open spigots up there somewhere.

 

JJJ
The convertibles are not the same as the coupes, I have no idea what the differences are though!

 

Hiya Greg,

Just to confirm, when removing the evap canister, all connections to the engine should be capped off? There’s connections to the manifold as well as the air intake so just want to confirm they should be closed and none should be open to atmosphere. Besides the small diameter pipe to the tank of course.

cheers

 

100% correct.
By the way, the other day I got round to taking a snap of the tank breather where bit comes out on the LHS by the chassis frame over the rear wheelarch, FYI:

 

Cheers Greg, I removed all that junk, cut down the vacuum lines, and plugged them with a screw and some RTV. Car works as before. Most importantly, my tank is able to breathe again. No more wooshing from the cap and a fuel vapor is notable when near that spout under the tank. I will eventually fit a small charcoal filter there but for now I'm glad its fixed. Thanks for the guidance!

Should that hard line to the tank get blocked, I'm guessing compressed air is the best/only way to clear it out?