Can someone please post a photo of the right way to plumb the fuel system in the trunk? I would like to replace all the rubber hoses but it also seems to be missing a pump. Thanks folks.

 

A 1977 would be a Series II, not Series III....which is probably why everything looks odd to me, as I know nothing about Series II particulars.

The single fuel pump isn't necessarily a problem, I don't think. However, it looks like it has two change-over valves....which seems weird.

I really can't make sense of it. Others will chime in.

Does this help?




Cheers
DD

 

Thank you guys, here is the diagram from my Haynes manual covering SI, II & III cars which shows and describes two pumps and two changeover solenoids.

 

Haynes is a bit notorious for not describing all the possible build configurations.

I think the two-pump configuration is for carbureted engines.

I'd seek out a genuine Jaguar manual, personally.

Cheers
DD

 

Series 3 fuel injection 4.2 just has one fuel pump on the right line this.

 

Malcolm,

You just may be... a Series II. Attached please find 2 out-of-focus pics of my Series II (1975, XJ12C) trunk fuel setup. Believe its OEM, still had the little paper Jaguar production tags on stuff.

 

definitely a series 3, correct bumpers, fuel injection, 1985 registered.

 

Thanks Coventrywood, your fuel system in the trunk looks almost exactly like mine. Are you running carbs or injection?

 

1977XJ5.3,

IF it was running, it would be injectors. 47 years and a coupla previous owners later, I should not claim the trunk fuel set-up is factory original, But the car has not run in decades & some of the trunk fuel hardware still have (had) the little paper Jaguar parts tags.

1977XJ5.3 is yours FI or carbs? If injected, where are you getting replacement injectors?

 

I think the system is plumbed correctly, I was dumb for assuming it wasn't. Fuel feeds in via the two large tank lines and tees at the first solenoid into the pump so the pump is only ever fed from one tank. The hose out of the pump feeds the block mounted to the trunk wall. The hose at bottom outlet of the block feeds the right line routed towards the engine and the top outlet of the block feeds the hose crossing in front of the spare tire to the tee at the far left. One outlet of this tee feeds the left hose routed towards the engine and the other feeds the second solenoid. That solenoid works with the first to make sure the return side operates with the correct tank.

 

Coventrywood, I'm still running the d jetronic efi. I haven't given up on the idea of trying to remove & clean the injectors since the o ring kits are still pretty cheap. Is that a fool's errand?

Also gambled on this, supposedly NOS old style 3 wire trigger board (with Lucas box!)

 

New on top, old on bottom.

​​​​​​

 

Sorry, I didn't have time to remove all the coverings to get an overhead shot but you can hopefully piece it together. This is a fuel-injected, UK spec, right hand drive car.


Photo taken from rear. Fuel filter is at the front right hand side of the spare wheel well.

 

Thanks markdpeter, I am also planning to add an extra filter in the trunk.

Does anyone know if the original braided hoses are the same as normal EFI hose from a parts store? It looks more like hydraulic line.

 

Where are people putting the extra fuel filter(s). Just changed my fuel pump and found it blocked with bits of rusted metal. Obviously should have checked thus when I changed the fuel tanks. So should it go between tanks and fuel pump?

 

I was going to add one to the hose coming off the pump. Can these old Lucas pumps be rebuilt at all?

 

Here is a picture of my fuel system in the boot. The hose you should use will be rated as "low permeability" and can be found a Marine supply stores, probably other outlets as well.

1/4 turn ball valves between tanks and filters makes replacing a dirty filter much nicer. I removed the change-over valve because it was leaking, replaced with common "T" hose fitting.


 

Thanks LT1Jaguar, does your pump run off both tanks simultaneously? I can't understand why Jaguar didn't do that in the first place.

 

The factory setup had an electric change-over valve where I have the "T" fitting. When the tank selector switch on the dash was toggled from left/right, it would direct fuel from the appropriate tank to the pump. At the same time, the two return line valves in the rear wheel wells would switch the fuel return to the same tank and the fuel level sender in each tank would change to that same tank.

When that system works, it works fine. When it doesn't work, it's not fine. There are a couple of slightly down sides to putting a T in place of the change-over. No mechanical separation between the two tanks means a leak in one will drain both tanks. If you fill both tanks and park with one side of car higher than the other, the high tank will gravity drain into the lower tank and over-fill it. That's another reason I put ball valves on each tank, I only run on one tank and leave the valve to the other tank shut off. Another irritation with the "T" is when filling one of the tanks, you are really filling both tanks, but that small T can't transfer fuel as fast as the gas pump is filling the tank. This leaves both tanks less than full, unless you wait at the pumps and keep squirting fuel in one or both tanks until they equalize at full.

Dave

 

Is all the fuel hose under the hood the same size? It all looks like 5/16 or 3/8. Maybe 1/4 from the rail to the injectors? Thanks again.