I drove to work today and then I came out and it would not start. Turns fine but seems like no gas or spark. I replaced the fuel pump in may and everything has been great. Could it break again so fast? It seems like the fuel pump again? I will try the relay tomorrow, but does any body have any other suggestions. a fuse?


thanks


rich

 

Its an XJS, it can break FAST. I am not too familiar with the 4.0litre lump, your problem could be something stupidly simple or a real nasty one. Have you checked the fuel cut off (inertia switch) and the simple stuff?

 

how do you check fuel cut off (inertia switch)?

 

I am not 100% of its position on the 4.0litre but a quick Google of XJS 4.0 Intertia switch found a fantastic PDF on your entire fuel system at Jagrepair.com. Check page 2 and 9, it gives you the layout and circuit diagram. Inertia switch is normally closed at creates open circuit on impact killing the pump. I suggest you grab a meter and start testing from the pump back if your confident its a fuel issue. That PDF has a wealth of info its well worth a read.


Others with more experience will chime in I am sure.

 

The inertia switch is a box with a button underneath it located on the passenger side of the dashboard, only accessible/visible when the passengers side door is open.

I'll take a picture if you're still unsure.

When activated, the fuel pump will not send fuel to the engine, so your symptoms would make sense.

It's readily accessible and takes you 5 seconds to see if the button needed to be depressed.

 

Do you discern any firing at all (indicating some spark) or is the engine just spinning when you crank?

 

the Inertia switch appears pushed. OK there. also the relay clicks but the fuel pump does not come on. I can't hear it at least. I did replace the pump 5 months ago, but did not change the wiring harness and I think the some fuel cut off wire may be fried. I notices that it looked somewhat cooked. Should have replaced everything not just the pump. I am limited in how much I can test as it is sitting at my office garage. bummer.

 

Cooked is nearly always bad, unless your talking about food. As a quick test you can always cut and block wiring. That link I referred too has a simplified circuit of your fuel system, the two main breaks are at ignition and inertia prior to pump. After that its down stream from the pump and you will need to start metering. That is, if you are sure its fuel. As Mii250 says, check for spark it could just as easily be a coil