What is the best way to purge the old fuel from the fuel system I so can start over? Do I have to take the fuel rail off?

 

If you think the fuel is merely stale then you can use the pump to pump it out. Disconnect the supply hose at the fuel rail (RH side of engine) and 'jump' the pump circuit to run the fuel pump. Do this by grounding the orange wire at the fuel pump relay and turning the key 'on'. Fuel will pump out very fast. Be ready.

However.....


If you know or even suspect that the fuel is contaminated (with rust or anything else) then you won't want to run it thru the fuel pump. I can't remember if the filter is before or after the pump. If it is after the pump then the pump is obviously getting unfiltered fuel. Someone will come along and tell us.

(I mention this because on at least some older Jags the filter is after the pump and guys have ruined their fuel pumps with rusty fuel)

Cheers
DD

 

To drain the fuel, push out (from underneath the car) the rubber bung in the boot floor under the battery/surge tank. Undo the sump plug in the surge tank bottom and drain the fuel into a suitable container.

Also, check the interior of the surge tank by removing the cover under the battery and knocking out the ring that seals the outlet pipe. Change the filter on the inside end of that pipe. Also, remove the spare wheel and change the filter behind it.

The refill with good fuel, and in the engine bay, undo the fuel union on A bank inlet side and with the key turned to ignition NOT start, pump a bit of new fuel through into a container. The pump will run for 2 seconds each time you turn on the ignition.

Hot wiring the pump to empty the tank is a bit iffy, IMO, because if it runs dry it only takes a few seconds to knacker the pump.
Greg

 

I removed the bung from under the surge tank. It appears that the drain plug doesn't align with hole in the boot floor. It would be easy to enlarge that hole. Is that normal or is the surge tank not in the correct location. What do you suggest?

 

Standard pre-Ford-Jaguar-era rubbish quality control I am ashamed to say. Either make the hole bigger (best idea IMO) or disconnect the main tank feed to the surge tank and drain the main tank that way, then unbolt the surge tank - which is a royal pain.

Greg

 

It looks like a design flub-up but actually it's what we refer to as "an interesting engineering feature".

Old Jags are plum full of interesting engineering features. That's one of the reasons we love 'em so much.




Cheers
DD

 

I guess I am lucky that my surge tank drain plug on my 90 XJS lines up. It was very easy to drain my tank... I hope it works out for you.

 

I think I'm almost there. I got the fuel all cleaned up and put in a new fuel filter. With great anticipation I tried to start it. I shot it with starting fluid and it would run for 3-4 seconds. I repeated the process several times with the same result. Frustrated I walked away. Convinced that its not getting fuel I got to looking at the Electrical diagram and checked to see if I had voltage to the injectors with key in the #2 position. I've got 12v on all the injectors. So I put a wire in the 8 pin connector for the injection harness on the ORG/BL wire and intermittently grounded that wire and I heard the injectors clicking. I repeated the process on the B bank. I tried to start the engine and it started without starting fluid but only run for a few seconds. I'm convinced the injectors are not functioning. Is it the ECU or am I missing a input to the ECU to make the injector circuit function? Bad ground???? You help is appreciated.