Jaguar Repair: Fuel pump 84 xjs, fuel pump relay, fuse panel

Question
When trying to start the engine the fuel pump never goes off and im afraid of engine damage from filling up cylinders .Can you give me any info to look for to remedy this problem. thanx

Answer
Hi Bill,
For the fuel pump to continue to run after turning off the ignition switch, the fuel pump relay must stay active either by being held active by the main relay or by the contact points in the fuel pump relay or the main relay sticking or a short in one of the circuits.

To trace down the problem you need to monitor the pink w/black tracer wire on pin #86 on the fuel pump relay when you turn off the ignition and the pump continues to run. If that wire does go dead, try unplugging the 45 second timer on the far left of the relay /fuse panel on the passengers side, to see if it turns off the pump. The fuel pump relay and main relay are in the right side panel of the trunk.

How long does the pump continue to run? and just because the pump is running there is no fuel going into the engine unless you have a stuck or leaking injector as they are closed when the engine is shut down.

Let me know,
Howard