Hi, I have just started playing around with my new 77 XJS.
I bought this as a "no starter" and am desperate to make sure the motor can run before spending too much time & money.

The car was last started 5 years ago, but does crank over. The tank is full of crud, so I am starting with the fuel system - purchased Fuel pump, filter, tank sump strainer/seal/retainer.
Here's my problem, I pulled out the tank today to get it cleaned out, but upon "releasing" itself from being stuck for 43 years, the rust on the tank floor has permeated and started dripping... tiny little pinholes. I've continued with the clean of the sump tank (absolutely filthy but will come up good). Finding a tank here in Australia looks like being a small miracle so it may be a while till I work something out there, with the last resort importing a new tank which is very very expensive... so is there anyway to start this car with only the sump tank? Not to drive it but just to crank and fire up the motor? will it work with an "open" fuel system?

 

OOPS.

Tanks may be at JagDaim, or Prestige Spares, both in Melbourne.

To do what you suggest would be kind of scary, but with HUGE care, doable.

A fuel supply TO the sump tank, as the pump is not a real sucker, it relies on a "head" of fuel from the sump tank.

Then the return fuel will need to be hosed off to an outside container.

Plugging a few smaller spigots on the sump tank should not cause any grief.

The crud you mentioned has possibly already found its way to the fuel rails, so I reckon a flush of those would the least you would need to do. The FPR's would be highly suspect, and the fuel hoses I would NOT trust, even for a test run, as engine fires from those hoses and V12's are way too common.

The V12 engine, particularly the PreHE is a strong unit, and near on indestructable. The fact it cranks over, is 90% of the worry gone.

 

Thanks so much, I'll be certainly checking/cleaning the rest of the fuel lines too.
Ive checked with both of those suppliers without luck, but i'll keep searching.

 

It should be possible for have the tank repaired. Few ways of doing it, there are sealants you can pour in and slosh around. They're readily available. Or it can be opened up and welded. Obviously make sure there aren't any fumes still in the tank when that happens. Steel tanks are really common in classic cars and there is a business in repairing them. I'm not sure what the market is like in Australia, but there's probably someone who does it.

 

Take the tank to a radiator repairers and ask them to spread a 1/4 inch of radiator solder all over the bottom surface of the tank. I have done this on two tanks and it works superbly. They can then pressure test the tank to ensure no other holes, which if found can get the same treatment. Then chuck the foam under the tank and replace it with a sheet of nitrile rubber.

Fuel tank floor soldered all over by the local rad specialist and then being painted

 

Wonderful suggestions, a friend of mine did something similar to a Merc R107 tank recently and he also suggested it... but I though my tank was leaking a bit too much.
Tried a radiator place today and he says he most likely can repair it with patching then a sealant/membrane, wont know for sure till it's cleaned up but seemed very confident. so it's in his hands now.

I was quite surprised, but maybe the tank isn't as bad as I first thought when I tore it out.


most leakage from bottom RHS and some more on bottom LHS

 

While I wait for the tank to return, I pulled out the foam fearing the worst underneath, but surprised at how clean that area was. Did however find a few concerns:
1. Bottom of boot looks to have a new section welded in. Not overly concerned as it suggests a previous owner may have done some of the hard work for me. Is it worth putting in a drain hole here? treatment?
2. the sides of the tank in the wheel arches. More weld-in patches?.. is it known to rust here in very isolated sections? only surface rust ATM.
3. Tried starting the car with quite a bit of "starter spray" and it seemed to grab for a millisecond. Tried again today, this time with a small amount of fuel in the cleaned out sump tank with new fuel pump and did nothing but crank.
Im suspecting injector related issues. reasons:
Got a good burst of petrol all over my arm when I removed fuel filter intake (under bonnet) and the return in the boot is spilling out fuel.
Removed a spark plug, it was dry.
Listening of click of the injector - page5 of "no start" guide but - hear nothing, my preHE doesn't have the resistor silver box as per guide.
I'm going to wait for the fuel tank to be refitted before following the no start guide further, but am I on the right track ?

tray under tank is really clean

Bottom of boot. drain plug needed?

Common area of rust?

New rubber

 

Yep.

PreHE for some reason are worse than the HE.

Take the rear seat out, its possibly migrated.

Rear window leaking is the most likely (common) cause. The seal shrinks under the chrome, and away it goes.

 

Yep, rear seat looks to have left the country a long time ago,.... repair look very sectional, I shall consider a previous owner has done the hard work for me and keep an eye on it from here

 

I think that all that rust needs properly treating, particularly in the corners and 90 degree sections where panels meet. I would use a blasting medium used in a compressed air gun and get it down to bare metal and see what is what. Then repair as needed and treat with AquaSteel and rust proofing paint. I think if you start jabbing at the rusty corners with a screwdriver you will get a shock. Some of those rusty welded in sections look guastly.

 

Have had a good poke around, it is all pretty well solid.. pics look worse than it is as there is a lot of old foam, flaky rust & gunky old petrol released due to tank removal/leak & very corroded battery tray. With bit of rust treatment/protector it'll be ok.
Bback seat removal look good, any moisture is the recent fuel tank leak seeping through those corners, car has been sitting for 20 years.




Abit more boring cleaning though

 

I’m not sure if the boot floor has been replaced near where the spare wheel sits. Can’t tell from the picture. The one where you say drain plug needed. On my 89 in front of the spare wheel holder on either side of the boot floor are two rubber grommets each side. These are in the shape of an elbow and are I believe breathers not drain holes. Two are close to the sump and two the other side. Petrol fumes are heavier than air and so sink to this area.during my restoration these vent holes got replaced with normal grommets and the underside was then covered in stone chip and under seal. A few inches behind these is a punched in set of weep holes or possibly vent holes again in the boot floor. These also got filled up with under seal making everything nice and air tight! I can’t see any of these but yours is an earlier car. Anyway I have been chasing a fuel smell for sometime and realising my error have now replaced the elbows and cleared the pressed vents. I am truly hoping this was my problem. It seems likely as the area they are in is not covered by the carpet and it makes sense. Others with early cars or more knowledge might chip in but if your floor has been replaced then you might need to look at this. Your new rubber covers an area in question. Regarding the main tank, mine was like a sieve. It went to a repairers who cut some large holes in it after chemically cleaning the fumes out. The inside was then shot blasted and patches re welded in. The tank was then lined both inside and out with a liquid liner. I have photos somewhere. The guy when he rang to say it was ready told me it was the worst they’d done. I bet you say that to all of them I replied. When I collected he showed me the photos. All good now . Anyway just some advice based on my experience. Good luck with it.

 

Update:
Tank refurbed, it took many weeks, there was that much gunk it filled a bucket, but happy to just have it repairable.
New pump, new hoses, even a newish battery tray which is like gold in these parts.
Need a new sender unit now, mine has 3 connections... what part # am I wanting https://www.ebay.com.au/itm/New-Jaguar-XJS-Fuel-Tank-Sending-Unit-DAC5500-NEW-/201462386674 ?

 

Damn, that just doubled the price of that car. Well done.

DAC5500 is the sender number I come up with also, and it would be 3 wire, the 3rd wire being to low fuel light trigger. Same as the HE unit.

 

FYI
On an HE, anyway, this photo shows which wire goes where on the sender:

Earth top left; gauge bottom left, warning light right.

 

Very nice looking repair job, I agree with Grant, doubled the price of the car. Lol When I purchased my parts car, I was told it had been a running driving car, and just quit starting one day. Was told it only sat a couple years, so I poured some gas in the filler, and all of a sudden I've got fuel running all over the floor of the shop. I caught what I could and found fuel all over in the trunk??? When I pulled the fuel tank, the right corner had a hole the size of a football! no damn wonder it quit starting. LOL!

Jack

 

I strongly suggest staying away from the pour it in, slosh it around, let it dry tank sealers. I ruined one with that crap.