Hi everyone, I picked up a 75 xj12 last week, 62000km carburated. it took us a bit to get it going but eventually it ran, I towed it home and got it running first try and went for a drive and stalled after a few minutes.
I listened in the trunk but couldn't hear or feel the fuel pumps working so I called the local shop (who said 4 weeks before I could bring it in) and he said to clean the points on the fuel pump so i did and got them working again. It seems if I let the car sit a few hours then try it will at least sputter and start and run poorly for a minute. The car has 62000km, all original and seems to he in mint shape, It sat parked for a few years and I'm trying to bring it back to life. What's the easiest way to check it's getting fuel? could the pumps be to weak?

Is there a fuel line under the hood I can pull off? Am I just new to a manual choke and flooding it? If I am is there a drain? Could it be not getting spark? I tried pulling the intake boxes off and using quick start but still just turns,

On another note my wipers won't work, common problem?

Sorry for asking a dozen questions, I just pulled my insurance off my truck and am hoping to get it going. It's a sweet car, original white wall tires and everything

 

You appear NEW, so welcome. I am assuming "edmonton" is in the USA??.

Pumps are now working, so under the bonnet RH side is the supply fuel line/hose. disconnect it from the front carby (I think, its been a looooooong time), and switch on the ign, and see if fuel flows. TAKE THE REQUIRED PRECAUTIONS, AS FUEL SPILL IS OBVIOUS. Being carby type, it will not be EFI pressure, but still a very decent flow rate.

The carby cars were prone to flooding, and those Stromberg carbies were a pain. The diaphragms inside the bell chamber split with use/age, and flooding is next.

The V12 carby ones I had required VERY LITTLE choke ever. So maybe best to leave it for now. NO drain, let it dry out on its own whilst you sit back and admire the beauty with a beer in hand, might take overnight if its really badly flooded.

Remove any easy plug lead, find an old spark plug, any will do, plug it into the end, and see if it has spark. The car will have the Opus ignition system, and there are PAGES of issues with that on any Jag forum.

A blocked fuel filter is real high on my list.

Stale fuel reeks havoc with carbies, so some fresh will do wonders eventually.

More will come once the basics are reported back. Patience is paramount here, so get that sorted before proceeding, coz these are nasty cars when they are sick/ill, just like us.

 

Thanks for the fast, handy reply. i just looked again and noticed one fuel filter is bypassed with a hose. The pumps are making a clicking noise, i was thinking they were working because they werent doing anything before, but i pulled the fuel line you mentioned and was dry. Would it make sence if the pump is priming and filling the lines but cant keep up so instead of flooding its starving for fuel and when whats in the lines runs out it stalls? I think its starting to make sence and my fuel pump rebuild failed. Can i use any junkyard xj fuel pumps? Or would it be cheaper to get a few aftermarket pumps and fuel pressure regulators? Maybe t the tanks to one pump? ... i really do love this car, ill post pics when i can get it out of the garage in the light lol. just ordered a haynes manual today .

 

OK.

The pump/s are "carby spec" by which I mean low pressure (about 7psi) and high flow. EFI pumps are high pressure (about 130psi non regulated), and also high flow. EFI pumps on a carby engine, just DO NOT DO IT.

The SU pumps are rebuildable with points kits, and diaphragms readily available. They rarely die totally. Mostly stale fuel screws the diaphragms, and a blocked filter really messes with them. The pick up filter (screen actually) inside each tank do get blocked, and that also stops fuel flow. Inside the "inlet" fitting of each pump is a fine brass mesh screen, give it/them a clean.

Junkyard pumps may be hard to find that are any good, carby cars are "old" now, so are the pumps.

I just got a diaphragm and points kit for an SU pump on a 1948 Rover P3, and now it runs sweet, old diaphragm was hard as plastic, and the points were really sad.

I suggest sorting the fuel supply TO the engine bay first and foremost, then step on from there.

Have a look in the engine bay, on the RH side at the rear (under where our brake booster is located on RHD), locate the metal fuel supply pipe, follow it forward, and you MAY find a valve looking adaptor in the flexible hose. It is a non-return valve, and Jag carby cars had them, and they block up. Remove it, replace the hose as required, try for fuel flow again.