After all the fuel system issues I had a few weeks ago, I've put on almost 1500 miles without any problems untill two days ago.
I'm driving on the freeway and It starts cutting out like the filter is plugged or pump is going out again. So I stop on the freeway shoulder take everything out of the trunk look at the glass filter I put on before the pump, and theres nothing in it. both tanks are almost full and Im stumped. Sat there scratching my head for about 15 minutes in 90 degree plus temps. and said try starting it. after a couple tries it starts. The trunk is empty still and I go look at the filter and there's barely anything going thru it. about 1/4 way flowing thru. I reached up and poped the gas cap open. Instantly filled up. so I threw everything in the trunk left the cap open and made it the 120 miles home with no problems.
I didn't know what to think other than it is vapor locking maybe.
Now theres today and I'm driving this morning with no issues. it started getting to the 90's and it did it again. The temp gauge is right at 100 where it's usually just under the green at about 89. I pulled over saw the rainbow discoloration around the gas caps, poped them open. it fired up and now I'm home.
I know the check valve is bad(I blow threw it back wards and it had no restriction, and I could hear the bubbling in the tank(. I did that two days ago.
Any ideas???????????

 

when you open the gas caps, do you get a whooossshhh of vapors and you hear the tank contracting ??

why not eliminate that non-standard filter you installed ?

you say you are in Colorado? what is your Altitude as it relates to Sea level ? These cars have an Altitude-compensation "something" mounted in the inner passenger side of the trunk. It is not documented anywhere.
I don't know what it does except a mechanic trained at Jaguar told me its name.

it is gold-anonized in color, and it has two red wires with white plastic connectors coming out of it.

check to see if it is connected or disconnected.

 

I couldn't say if I heard a whoosh or not since I was on the freeway shoulder with tons of traffic flying by, but I saw the fuel increase as soon as I popped the cap. Today as I said, I didn't watch it I just popped the caps and it fired right up.
As for the clear filter, I installed it a bit ago trying to find out if there was rust in the tanks and now the hose is to short if I remove it and being a 7/16 line, I can't get the biggest hose available to go onto the fittings. I have to order it from somewhere. Also I just figure more filter is better for the moment, it shouldn't hurt anything.
I'm at 5500 feet elevation, the gold looking thing is right by the pump, I originally thought it was a check valve but it has two black wires going to it. I've never known a check valve to have electrical connections. I took some pics, lets see if I can post them. Nope, I can't figure out how to post them. but the goldish part is a junction for the two tanks. 1 comes in the left 2 comes in the right and then one comes out to the filter I installed then into the pump.

 

the gold-anonized component I am referring to, (Altitude Compensator), is located below and to the right of the right trunk lid HINGE.

remove the right side carpeted panel, then remove the inner horizontal carpeted panel held by two black plastic screws, behind which you can see many electronics, sunroof motor, etc.

if you lay inside the trunk with a flashlight, looking under the trunk lid's right Hinge,
(passenger side), you might see it bolted to the body there.

Yes it sort of looks like a check valve, like a drum cylinder with two halves.

I really do not know what it does, all I know is what I was told.

 

Thank you Jose, I will check that out in the morning and let you know what I discover.

 

The altitude switch sends a signal to the ECU....it's just a fuel mixture trimming device. In won't have any bearing on gas tank venting.

I think Jose is on the right track with the whoosh question. Even though you didn't/couldn't hear a whoosh I'd disconnect the vent hose at the little valve in the RH front fenderwell....which will allow the tanks to vent to atmosphere and should eliminate the possibility of any suction/vacuum/pressure issues inside the tanks. See if your problem changes or goes away. Jose has a picture of the little devil. Easy to do, and free......so it's painless as experiments go.

Cheers
DD

 

Doug, Thank you. this sounds a bit more to be an experiment that could be worth trying. Especially since it shouldn't cost anything, but if it is the answer then I'll probably need to know what the fix is. I guess at this point I need a better description of "the little valve in the RH front fenderwell."
Jose, can you show me the picture of the "little devil"?
I'm going to go look now, but the description here is pretty vague.

 

Well I think I see what you mean, if you are referring to the outer fenderwell where the tire is. I see a valve under there with a "vacuum" line going to it on one end, what looks to be fuel line on the other and then another line going to the canister under there. Is this what your referring to? easy enough! I don't remember what these canisters do, is one brain fart I'm having. In my past hot rod building, I always took all the emission crap off and tossed em, all they did was rob power so I had no desire to use them or even pay attention to what they did. I would listen now if someone wants to explain it to me, but I'm also more concerned with getting my issue pinpointed at this moment.
If this is the fix, then what is the bad part that I need to replace? The valve, the canister, or something else? Or is this even what your talking about?

 

From memory the are 2 or 3 valves on the vacuum/vapor lines near the canister. You want the one that is situated horizontally aft of the canister. One nipple of the valve points forward, the other points aft. Disconnect the hose from the aft-facing nipple. Your tanks are now vented to atmosphere.

If the solves the problem then the 'fix' for many of us is to leave it disconnected. Or, remove it and drill out the innards and reattach the hoses. Or replace with new.

That operation vapor system is a little tricky and fading memory does help. The valves open in one direction at xxx-pressure but yyy-pressure in the other direction....but only on odd Tuesdays below 70ºF going uphill.

Jose will remember more.

The vapor recovery system won't rob any horsepower so if you can make it operational with little effort or expense, you probably should.

Cheers
DD

 

Thank you for the clarification Doug. My only concern is debris getting in if I leave it disconnected for a lengthy period, but weather should be good for a week or so and I have another 300 mile trip in the next few days to test this theory out.

 

What is this?

 

Looks like the 'changeover' valve in the trunk. When you operate the tank switch on the dash this valve opens/closes to allow fuel from the left tank or right tank....but not both.... to flow into the fuel pump.


Cheers
DD

 

Thank you. One more Question. Where is the fuel check valve at?

 

The check valve or non-return valve is in the trunk. It is screwed into the air bleed assembly.....which is near the fuel filter in the spare tire well.

Item #5 in this illustration


Fuel Feed Pipes and Hoses-Trunk - Parts For Series III Saloon | Jaguar Heritage Parts UK


Cheers
DD

 

Thanks again Doug!!!

 

That seems to fixed the issue. such a relief!!!
although I had another tranny issue develop yesterday. can I talk about it here or should I start a new thread?
The tranny I replaced a few months back started doing the same bs that the last one did. I babied it home, and would like to know if someone know how to fix it at this stage or if there is a rebuild kit and instructions somewhere.
If I don't get a response in a couple hours here, I will start a new thread.

 

best to start a new thread. search first though. the most common problems are low fluid or loose brake bands. both have been covered more than once. Glad the fuel problem seems to be fixed.

 

I tried to start a new thread a few minutes ago. I got it all typed went to post and my internet chrashed. Im on phone now. I'll talk to you all later when internet back up.

 

What did you do?


Cheers
DD

 

I disconnected the line under passenger wheel well at valve to vent into atmosphere. Now I'll look for a new valve or drill out(last resort) the one I have. Doug turned me onto this experiment. Thanks again Doug.