XJ XJ6 / XJ8 / XJR ( X350 & X358 ) 2003 - 2009

Fuel pump run after shutdown?

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Old 12-18-2017, 11:49 AM
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Default Fuel pump run after shutdown?

When I shut my car off in the garage, I can hear what sounds like some kind of pump or motor running from the rear. It isn't like any fuel pump noise I've ever heard, I actually thought it was the parking brake repeatedly trying to apply. But I have held the p-brake off many times while parking and the noise is still there. It will make the noise for about 1-2 minutes then stops with an odd "creak" noise.

I've noticed the car has been doing this more frequently, first noticed the issue 3-4 years ago but it only seemed to do it in the winter. Now will do it any time I park the car.

Is this the fuel transfer pump running after shutdown? No issues with the fuel gauge indicating the correct level. No issues starting or with fuel pressure. I can't isolate the noise to either left or right, it sounds like it's right above the rear axle. Curious if anyone else has heard this.
 
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Old 12-18-2017, 12:52 PM
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Originally Posted by mhamilton
When I shut my car off in the garage, I can hear what sounds like some kind of pump or motor running from the rear. It isn't like any fuel pump noise I've ever heard, I actually thought it was the parking brake repeatedly trying to apply. But I have held the p-brake off many times while parking and the noise is still there. It will make the noise for about 1-2 minutes then stops with an odd "creak" noise.

I've noticed the car has been doing this more frequently, first noticed the issue 3-4 years ago but it only seemed to do it in the winter. Now will do it any time I park the car.

Is this the fuel transfer pump running after shutdown? No issues with the fuel gauge indicating the correct level. No issues starting or with fuel pressure. I can't isolate the noise to either left or right, it sounds like it's right above the rear axle. Curious if anyone else has heard this.
EPB
 
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Old 12-18-2017, 05:05 PM
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Originally Posted by Box
EPB
The parking brake is *off*

...

This is a pump noise, which only starts about 5-10 seconds after I shut down the car. Then it starts making a thumping noise, which can be felt in the tank. This noise is not the exhaust tinwork cooling. The pump can be heard running for about 2-3 minutes. At the end some more odd noises can be heard from the tank. Here are 2 videos from today that capture it:

Start of noise:

Ending noise:
 
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Old 12-18-2017, 05:35 PM
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That is the parking brake, trust me.

The EPB is automatically applied, if you don't apply it yourself beforehand, when you remove the key; you have to hold the EPB switch down while you remove the key to prevent that automatic action.

The EPB has lost its position sensing function somehow and the clicking/bumping is the cable wind mechanism somehow jumping back when the torque gets too much.

The slowing down grinding noise just before it does stop is absolutely the noise mine made.

Try a battery disconnect 'reset', that might sort the PBM; probably won't but has to be worth a try.
 

Last edited by Partick the Cat; 12-18-2017 at 06:55 PM.
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Old 12-18-2017, 07:46 PM
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I did hold the button down while I removed the key. Been through several battery resets, no issues resetting the brake. It also holds fine. I use the parking brake frequently at drive throughs. Tomorrow I will pull the epb fuse when I get home just to eliminate any doubt.

Patrick, did your issue set an epb fault or othwwise have the parking brake not working?
 
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Old 12-18-2017, 08:19 PM
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I have to apply brake, push brake lever down and turn car off to overide the EPB from engaging.
 
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Old 12-20-2017, 10:21 AM
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Originally Posted by mhamilton
Patrick, did your issue set an epb fault or othwwise have the parking brake not working?
I kept getting 'Parking Brake Fault' and each time I cleared it using the SDD and did a Parking Brake Reset it occurred immediately afterwards.

I had a new parking brake fitted but the fault was possibly due to water under/behind the rear seat where one of the connectors is situated (I'd left one of the rear windows open overnight a few times when it had rained). That would definitely be worth checking before you embark on replacing the brake unit or its control module.
 
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Old 01-10-2018, 09:29 AM
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Sorry for the long delay replying to this--holidays got in the way and for a while the noise was not occurring at all.

I finally had a chance to look at the wiring diagrams for the parking brake (see below). Here's where I'm at:

1. If I hold down the parking brake switch while I remove my ignition key, the brake light stays off, car chimes, and I know the EPB doesn't apply because the car rolls slightly against the parking pawl in the transmission when I take my foot off the service brake. The noise still occurs.

2. With the noise occurring, I pulled fuse F32 (30A) from the rear box. This should be the feed for the EPB motor. The noise continues.

Based on the above, I'm nearly 100% positive that the EPB motor is not the source of this noise.

The only other test I can do is to pull the power from the fuel pump, but it's powered via the REM. Fig 3.4 shows there's a 20A F32 in the rear block that appears to power the fuel pump motor, I may try pulling that. Unfortunately the fuel pump relay is the internal type, so I can't just pull that from the fusebox.

Unless there is something else under the rear of the car that could be making this noise? It's not coming from inside the trunk around the area of the air block.



 
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Old 01-10-2018, 04:01 PM
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Old 01-12-2018, 08:10 AM
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Originally Posted by meirion1
Thanks--I'll look for that connector. Is it on the subframe?
 
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Old 01-12-2018, 03:26 PM
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The EPB is mounted on top of the diff.

The cable may go though the body and plug into the

module in the boot which would make it easy.

On second thoughts I don't think it's long enough.
 

Last edited by meirion1; 01-12-2018 at 03:44 PM.
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Old 01-17-2018, 06:31 AM
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Thanks--I'll take a look. I think I can unplug the EPB module in the trunk, just have to get access to it behind the REM.

I pulled both of those fuses while the noise was occurring (one for the EPB and one for the fuel pump)... still had the noise. So now I'm more confused. I agree pulling the connector will be definitive.
 
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Old 01-17-2018, 03:24 PM
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Can I just say that you have had so many problems with your Jag, you have been very

unlucky.

I scraped a wing on mine pulling out of my garage yesterday. First scrape in ten years

of ownership. I can't complain when I compare my luck to other owners!.
 
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Old 01-17-2018, 06:29 PM
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Originally Posted by meirion1
Can I just say that you have had so many problems with your Jag, you have been very unlucky.

I scraped a wing on mine pulling out of my garage yesterday. First scrape in ten years of ownership. I can't complain when I compare my luck to other owners!.
Surprisingly, it has been relatively trouble free. The noise from the rear is an anomaly but everything is functioning. My pickiness has me trying to solve that. The surging is the only recent issue. Before that the only things to note were front air springs, rear control arms, trans cooler lines, and a couple motor mounts.
 
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Old 01-23-2018, 12:03 PM
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Stumbled across this in the '06 schematics. North American Spec vehicles come with a "Leak Detection Unit" which is part of the carbon canister above the fuel tank. It actually is a little motor that (I assume) pulls a vacuum on the tank after shutdown to check for leaks. This would explain why the noise has nothing to do with my parking brake. It also explains why it seems random in operation, as the PCM would do evap testing based on a range of fuel levels (typically on GM cars evap purge/seal testing only occurs between 25-75% fuel level).

I will pull the 10A ECM switched fuse next time I hear the noise and see if this stops it.






 
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Old 01-24-2018, 04:33 PM
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Originally Posted by mhamilton

I will pull the 10A ECM switched fuse next time I hear the noise and see if this stops it.
Got to test my theory today--the noise I'm hearing is 100% the evap system running its test after the car shuts off. In fact, now I realize that the thumping/creaking noise is not the pump itself, but expansion of the fuel tank (theory of operation is the PCM pressurizes the fuel tank/system with 3-5 psi or air and checks for leakdown). I pulled F12 (underhood) and the pump noise immediately stopped. However the tank creaked a moment or two longer.

Since I'm not getting any errors or CEL due to an evap issue, I'm not going to bother it. Made me cringe thinking it was a failing fuel pump or parking brake. Now I'm happy to know this is a normal function of the car, even if the creaking is a bit unnerving!
 
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Old 07-04-2022, 01:22 PM
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Default Same issue

Originally Posted by mhamilton
When I shut my car off in the garage, I can hear what sounds like some kind of pump or motor running from the rear. It isn't like any fuel pump noise I've ever heard, I actually thought it was the parking brake repeatedly trying to apply. But I have held the p-brake off many times while parking and the noise is still there. It will make the noise for about 1-2 minutes then stops with an odd "creak" noise.

I've noticed the car has been doing this more frequently, first noticed the issue 3-4 years ago but it only seemed to do it in the winter. Now will do it any time I park the car.

Is this the fuel transfer pump running after shutdown? No issues with the fuel gauge indicating the correct level. No issues starting or with fuel pressure. I can't isolate the noise to either left or right, it sounds like it's right above the rear axle. Curious if anyone else has heard this.
I have a very similar issue with my 2010 XK it appears the fuel pump continues to run after the car is turned off and it admits a very strong odor of gasoline for a few hours inside the garage.
 
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Old 07-04-2022, 02:16 PM
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sometimes the dmtl pump runs

only federal cars do this as far as i know
 
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Old 07-04-2022, 03:48 PM
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Default Could not find a pump

I searched everywhere for a pressure pump but couldn’t find anything for the XK model. I can’t find any fuel leaks. The fuel smell is strong for hours after I park it.
 
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Old 07-04-2022, 05:39 PM
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Originally Posted by Dave of Texas
I searched everywhere for a pressure pump but couldn’t find anything for the XK model. I can’t find any fuel leaks. The fuel smell is strong for hours after I park it.
look up volvo dmtl

it sits above the diff
 


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