Fuel pump relay
 

So my plan is to change out the fuel pump and filter. If I have it right, to depressurize you pull the relay in the black holder, not the red one. Crank it over and you're ready to go. I tried that but the engine keeps running..and running. No sign of it wanting to quit. What did I miss?

I pulled the cables off the pump. Wrapped them in a rag to prevent sparks, then started the engine until she stutters. Then turned it off.

Worked for me.

Craig

Hi Jag-reflex

How long did you let her run for?

A few minutes at least..not long enough?

Sure, that would definitely do it, but so should the relay pull..I'm wondering why it doesn't. Push comes to shove i will follow your example, but I'd rather understand the puzzle too.

Thanks

Maybe you didn't have her running for quite long enough?

Possibly I guess, but i would have thought less than a minute with no pump running. I will give it another go in the morning. ..

You might check if a previous owner or mechanic may have modified the relay circuit as mentioned in this post:

https://www.jaguarforums.com/forum/x...0/#post2058300

Might explain your circumstance.

I have the 16CU so no reason for someone to do that, which doesn't mean it wasn't done of course. I will check that, thanks.

With the Black socket relay pulled, a few seconds is all you will get.

My thoughts:

Someone has bridged the actual Black Block, on the underside, to run that pump whenever the Ignition is ON. Reasons, NO IDEA, other than issues and did so for diagnostics and forgot to remove.

Earthing that Orange wire will only work to run the pump whenever the Ignition is ON, IF the relay is installed, so even with that, pulling the relay will kill the pump.

The relay in the Red socket is the Main relay, and that operates the Pump relay, the ECU, etc etc, so pulling that will NOT start the engine, as the ECU is dead.

Yes. found the jumper wire underneath. thanks Grant

So I swapped out the fuel pump and filter. Popped the relay back in and cranked..no start. Reconnected the jumper wire and fired right up. I'll pick up a new relay next..

Thanks to all who chimed in on this thread.

Edit: new relay fixed it. Stupid jumper wire now in the bin. ta-dum