My fuel pump may be done for in my 4.0. From all research the FP is in/ around the fuel tank. Where can I find a video of how to remove and replace it? There's nothing on you tube for this model that I can find. I'm not good with diagrams, I'd prefer a video or at least step by step photos. Any advice out there?

 

VCM Error Code PAO

 

PAO=PAD
brake pad getting low, time to change or short in sensor in pad

If the fuel pump has gone, you have to remove the fuel tank to change it.

Larry

 

Thanks Lawrence. But car will not start.... the pads are low, but that would not keep the car from starting would it? I was checking code that would point to that problem. Has symptoms of bad fuel pump, but now I'm not sure.

 

No, that's just a brake alert - if it just appeared you are entering the last gasp of the pads - it generally means get some new ones soon before you score the rotors.

Do you have fuel? How is the distributor rotor? Does the rev counter show ~200rpm while cranking? Why did you suspect the pump before and not now?

Larry

 

Hi JagBro,

I'm in a hurry so this won't be in-depth, but a few basic checks you can do include the following:

Turn the key to position II (ON) but do not crank the engine. Listen for the faint sound of the fuel pump running for a few seconds to prime the system. If you hear the pump run, that's a sign that it is not completely dead, but it may be failing intermittently.

If you do not hear the pump run, the pressure in the fuel system may be adequate and it may not have been triggered by the ECM to do a priming burst. A quick check for fuel pressure can be done by laying some rags under the fuel line fitting at the inlet end of the fuel rail nearest the firewall. With two wrenches, carefully loosen the fitting to see if fuel sprays out under pressure. If no fuel sprays out, try turning the key to position II again without cranking the engine and watch for fuel spray.

Power for the fuel pump in a 1991 comes from fuse C8 (25A) in the left A-pillar fuse box. The ECM activates the fuel pump by connecting the ground side of the fuel pump relay to ground by way of the oxygen sensor.

You can download the wiring diagrams here:

Jaguar XJ40 Electrical Guide 1991

A problem with the oxygen sensor can prevent the fuel pump from running and will often trigger a diagnostic fault code, but you may not be able to see the code on the VCM while the PAD warning is illuminated. The PAD warning is typically triggered when a brake pad wear sensor wire loop is broken due to contact with the rotor. A temporary fix is to cut the sensor harness, strip the wires and twist them together. This should extinguish the PAD warning.

If your fuel pump relay is the standard "ice cube" type, you can temporarily swap in a less important relay (radio, horn, etc.) to see if the fuel pump relay is the problem.

Using the Electrical Guide, you can test for 12 volt battery power between terminal 30 of the fuel pump relay socket and ground (with the key in position II). If you have power there, you can use a large paper clip bent into a U to jump between terminals 30 and 87 in the fuel pump relay socket and the fuel pump should run. If not, check the wiring between the fuel pump relay socket and the fuel pump. If the wiring is sound with no damage, the fuel pump is probably dead or dying.

Cheers,

Don