Hi Everyone

Really hoping someone can help with my poorly XJS!

It is a 93 facelift model 4.0 manual, working fine up until a few weeks ago. The engine will turn over fine but the fuel pump is not running. I have checked the inertia switch which is fine.

I have connected a multi meter to the pump and there is no power to it so pretty sure the pump is ok and it's just the feed to it. Have tried a different fuel pump relay which made no difference. Interestingly there is no power to the inertia switch either so I assume this is after rather than before the pump in the circuit?

The other strange thing is that none of the guages or warning lights etc on the dash are working either. Do these only come on if there is power to the pump in other words are they fed from the same circuit?

Really hoping someone can help as it's just a big green lemon on my drive at the moment.

Andrew

 

This sounds like the main load relay, the one that powers most things into life when the ignition is switched on, has failed somehow. I would start there.

 

Thanks Greg

The interior lights work, windows mirrors etc are these on a different relay??

 

yes

 

Hi Moonscape

Check this out:

LHD Car Right Hand Side Fuse Box (That's the one by the knee bolster)

Fuse Number:10 Engine Control Module Relay

Fuse Number: 20 Engine Management System Power Relay

There is also another Fuse Box in the same position on the other side of the Car and it's also a very good idea to systematically check all the Fuses in these 2 Fuse Boxes by the knee bolsters

Also Most Important as in 'Mega Important' is to have a look just above these Fuses and you will see 2 Blue Relays, which are know to go 'Flakey' as the Blades of these 2 Relays sometimes lose contact with the Holders they are plugged into

Simply Pulling out and reinserting these Relays, can re-establish a lost contact and if that doesn't work replace it/them with a Relay of the Same Value that has 'Thicker Blades' (Note these are Not Normal Relays as they have Diodes and cannot be swapped for Relays without diodes)

With my Car a 1995 4.0L XJS with AJ16 Engine, I had exactly the same problem as yourself and it was this Blue Relay that finally got her going and that was after trying, almost every trick in the book!

You can read all about it here, including loads of Photos and Photos of the Location of those Blue Relays, which might save you a couple of Weeks of going round in circles while trying to find the fault

Click on the Link to Page: 93 below

'Carmen Won't Start' Chapter: 93 'Trying almost every trick in the Book to get my 1995 XJS 4.0L XJS to Start which turned out to be a Blue Relay under the Passenger Side Knee Bolster Fuse Box on a (UK) Car USA Spec may be on the other side