Made it from Baltimore to St Louis. Filled the gas tank 5 times.

Each time I opened the fill cap, lots of air rushing in, accompanied by Loud whooshing sound. Obviously something with evap control system.

stanrgely, there was a steady stream Of petrol coming from one of the small holes surrounding the filler flange. Each time it went on for several minutes. What is that?

Is there a quick fix for the tank vacuum problem? As it out in the parking lot of a motel?

 

Uhhhh. Shouldnt be any steady stream of anything on the car from anywhere.

The tank vent and carbon canister is a clusterfk of hoses and nonsense your better off tearing it off, as your nowhere near a home garage with tools I'd suggest just not tightening the cap down for now? Some people here drill a tiny hole in the cap itself (1/16th drill bit?)

 

Scott
When you get home (having done what Vancouver suggested in the meantime) you will have to look at the OEM tank ventilation system. The symptoms you are experiencing are caused by the fuel being pumped out and used; but air not being able to get into the tank to replace it. Hence the small hole in the cap to allow it. This should be done ASAP or the tank can collapse.
If the rules allow it, the best thing to do, in my opinion, is to install a modern valve and vent it to the outside. This is the sort of thing:
https://www.merlinmotorsport.co.uk/p...-tails-m-trl88

The OEM system at the tank end is shown here: https://parts.jaguarlandroverclassic.../brand/jaguar/
and here
https://parts.jaguarlandroverclassic.../brand/jaguar/
You will find three hoses (26 in the second diagram) leaving the top RHS of the tank to the cannister (just above 13 in the first diagram, 21 in the second). Cap two and insert the valve into the third, I think it has to be upright, and then run a tube to the outside. Then everything else can be junked.

 

Yes the pump moves a lot of fuel, huge negative pressure we can talk about junking the useless carbon canister vent system later please leave the cap loose and let us know when your back to home base.

 

Thanks for the advice. I will leave the cap loose for now.

My new home base is my marina in Seattle. Working on cars isnt allowed there. So the car will no longer be a garage queen. I have to find somewhere to work on it (and the Porsche, Benz, and TVR).

 

This forum comes through again. This is my issue too. I cracked the gas cap and it launches off the line now and even spins the tires a little.

 

A very small hole drilled into the side of the mounted decorative gass filler assembly worked for me. Not to the decorative silver/chromed bit, but to the casted frame underneath. A hole that will allow fresh air to be pulled into the neck, tank system

 

So, I drilled my vent hole today and put the rubber stopper back on the chrome lid. While I was at it, I tried blocking off the two vacuum ports on the LH manifold. That really smoothed out the off-idle response.

This group is great. I really appreciate all the advice I have received here.