Hello all:

When I shut off the engine on my 2001 Jaguar XKR, I can hear the sound of a pump or electric motor running for maybe 30 seconds. Can anyone tell me what is generating the sound?

Very respectfully, Bob G in Florida

 

It could be the cooling fans. My 97 fans used to run for about 15 sec. if the engine was fully warmed up.

 

Agreed - fans run on after engine is switched off.

 

Hello RJ237 and David. Thank you David for helping me AGAIN.

I am afraid I have to add more information. I've had an intermittent electrical short. Last evening I opened the garage to make sure my wife closed the garage door. The car had not been running for hours. Then I heard the motor or pump running. I pounded my fist on the fender and it stopped. This morning the battery was dead.

If I could find out what is making the sound, I could add a switch in the circuit until a proper repair is made.

 

Bob, if you have to hunt it down you could pull fuses until it stops. Then you found the circuit.

2x check the ignition key slot door, does it close?

Excuse if that's too obvious, sometimes we get so close to these things we overlook something.

John

 

Hello Johnken.

That's a great idea. I never thought o fit. Guess I'm too close to the problem.

When the battery gets a full charge, I'll try that first.

Very respectfully,
Bob G in Florida

 

I think you need to "hope" that it happens again, and then identify the source of the noise. The fans are designed to run on after the engine has stopped and the keys are removed, so it is possible that one of the fan control relays is sticking and not allowing the fans to stop after the required period. That would be my first guess, but ..... it may be something else.

The relays are close to the wing / fender so that's a distinct possibility !!

 

Check the intercooler water pump under the air box, as another source of electrical noise. XK8 here, so I have no direct experience.

 

Thank you fmertz. Great photo. Brings back old memories. Yes, the intercooler water pump. As soon as the battery is charged, that will be one of my first tests.

Very respectfully, Bob G in Florida

 

Hello all:

Making progress while battery is charging.

I've been leaning all over the engine compartment, which is hard when you're in your mid-70s.

Identified a possible culprit. See photo.
Fan wiring no longer held by plastic clip. Was pressed against serpentine belt pulley and frayed the jacket, maybe wires also.

So, I am unable to reach and secure with a plastic tie. Have to remove the fan/shroud first, or grow small hands.

I have not identified any frayed or loose wiring on the intercooler, or on the throttle body/position sensor.

Maybe the fan was making the noise, until the battery drained?

Very respectfully, Bob G in Florida.

 

with all due respect, pounding your fist on the fender is not doing the car or your fist any good. A different strategy is advised.

Z

 

Bobg, not sure if you ever did fan shroud b4. Watch those top nuts that look like the are captive in the plastic - they are not and can get lost easily.

Good news is it's a easy job once you secure the hood in full open position.

Thanks

John

John

 

Hello Johnken.

How very perceptive of you. Yes, the top nuts were both missing from the shroud. It was tipped away from the radiator towards the engine. When I pushed it back towards the radiator, that is how I notices the damage to the fan cable. Now I'm waiting for my wife to help me secure the cable with a zip tie.

Very respectfully, Bob G in Florida

 

Hello all.

Problem SOLVED. Thank you again for your patience and help for the past several months.

Now I know more about the failure mechanism and ultimate solution that I had ever thought was possible.

The radiator shroud was not properly secured to the back side of the radiator. It was tipped toward the engine.

The CLIP on the wiring to the cooling fan was broken. Ultimately the wiring engaged a pulley for the serpentine belt. The pulley cut through the jacket and insulation until the bare wire touched the pulley.

As long as the car was running, this short did not have an impact, other than the fan running.

However, when the engine was off, the intermittent short grounded one of the wires. This is the OG wire on the RH radiator fan.


Wire OG, upper right, is supposed to be +12V when starting the engine. It was intermittently grounded against a serpentine belt pulley, sending Ground to the ECM. This was confusing, so the ECM prevented the car from starting.

----

That's why banging on the dashboard, and more recently on the fender temporarily solved the problem, by allowing the wiring to move away from the pulley. Who said just get a bigger hammer.

(See diagram attached, top right upper area.)


When the engine is off, if the wire did not make contact, the engine started. However, if the wire was grounded, PINS EM81-04 or EM81-05 to the ECM were grounded. They want to be +12V. So the ECM is confused, and refused to allow the car to start.

Once I tied the frayed cable up with a plastic zip tie, I eliminated the failure (ground), the ECM was happy to see +12V, and the car immediately started.

All the other dashboard lights and warnings went away.

Thanks again for staying with me during my 4 months of pain. It really helps to have a friend to bounce off thoughts and assumptions.

My very best to MichaelH in Jersey, Channel Islands, for his continuous help.

Very respectfully, Bob G. in Florida

 

Great news Robert. I guess it is a bit like finding that the reason your toe hurts is because you banged your head but that's the way with the electrickery on these cars.
Congratulations on your persistence !!

 

Thank you David. Your 3,500 mile away diagnosis of the fan was spot on. Imagine, a frayed wire confusing the ECM in an unrelated way. I guess banging on the dashboard, fender, and other parts were just enough to break the short between the frayed wire and the pulley.

This problem has been plaguing my car for many months, including replacing the inertia switch (a secondary failure) and the ignition switch (another secondary failure).

I sure miss my old XKE. Just 8 fuses and maybe 4 relays.

Very respectfully, Bob G in Florida

 

I sure miss my old XKE. Just 8 fuses and maybe 4 relays.

In some ways I miss my old Sunbeam Alpine - Three fuses, one relay, and a wiring diagram that took up one small page of the handbook.

But - I wouldn't exchange my XK8 for it even if it was still going which frankly, I doubt !!