Hi I’m new here and pretty new to Jaguar ownership so anyway here’s what’s going on I bought a wrecked xjs v12 5.3 pre HE and I guess at some point before the wreck the fuel pump would not start so it was bypassed there is a sort of jumper wire coming off both of the positive and negative battery terminals the one on the Earth (ground) was jumped somewhere as well as the positive it was wired to a type of bypass switch which manually started the fuel pump when the car was wrecked the battery was launched around in the trunk because it wasn’t secured well. Anyway the assembly was pretty messed up the red (positive wire) was ripped out from were it was jumped and so was the ground wire, I’ve spliced the ground into the 85 (orange wire) coming out of the fuel relay fuel pump now turns on and off but my issue is I have no idea we’re the positive wire was sliced to and the fuel pump only stays on for the first two turns of the ignition (key) then the pump shuts off on the third and when the car is turned over fuel is not being delivered therefore the car will not turn over or run, it might fire if I let the fuel pump run on turn two of the ignition for a bit then turn it over and it will fire. Any ideas?

 

Welcome to teh Forums.

When time permits, please do an Intro in the New members Area.

A 1985 IS a HE, NOT a PreHE, so please clarify the build of the beast, as diagnosis is very different.

BUT

The Orange wire splice in the boot is a 85% HE give away.

The pump runs, BUT, does it pump fuel?? The pump may be wired **** about face, it is sooooo simple to do that, and the thing will buzz and whirr, but only pump fuel the correct way round. Make sure the +ve lead is actually ON the +ve marked terminal of the pump. Forget what is there, may be there, start at the beginning, and work carefully.

It that is OK, crack the fuel line at the A Bank Rail connector, and try the pump again. THERE WILL BE FUEL SPRAY, so please be bloody careful.

Once that is sorted, my sticky at the top will guide you through the rest.

The system is SIMPLE, so dont over think it.

 

Thanks for the advice.