Hey guys i have a feeling one of my relays is bad. went for a ride this morning, and when i got back home and turned the ignition key off my car stayed running....Before i jump to the ignition tumbler i,m wondering if its a stuck relay. I pulled out the first relay from the lights on the drivers side, ( left side ) and the car shut off.. I do believe that's the fuel relay????? Thanks in advance

 

Hi Kriss
The Fuel Pump Relay is in the Boot Trunk up underneath the Fender/Wing drivers Side on a UK Car near the Boot/Trunk Support Strut but you will have to remove some Trim in order to get to it or even see it, as its tucked right out of the way

It sounds more like an Ignition Switch problem to me, although that's a bit of a guess



This Photo is from my 1995 XJS 4.0L

 

The fuel pump is powered first by the Engine Management System(EMS) relay which is powered by the ignition switch (see diagram). Yes, by pulling the fuel pump relay, you would kill the engine, but that would happen anyway. You have to see if you still have power before and after the relays to suspect that either the EMS relay or the FP relay has not opened/deactivated as it should when turning the ign switch to off.

input power to EMS Power Relay is "51"


"51" comes from Ign switch output through fuse 7 of Right Fuse Panel to Inertia switch to "51". Check at fuse 7 if you have 12v when you should not have when Ign switch is turned off if engine is still running.



If engine still runs after Ign switch is off, the only place where 12V could come from is the ign switch to power both the EMS and FP relay. There should be no power at EMS or FP relay. Even if one of the relays were stuck closed, removing power from them both should kill the engine. You ca also actuate the FP inertia switch to see if it kills the engine.