Now, I know this is about as difficult as asking a blind man to choose the paint color for your kitchen, but here goes.....

I am steadily working through the few things that needed doing on my new to me XJ40.

I am confident I know how to fix everything except this weird noise that I have been unable to trace.

It sounds like someone is drumming on something. I have had cars where the exhaust was touching a chassis leg at idle and that's what it sounds like.

It is only audible inside the car. You can hear it in every seat. It sounds like its coming from the rear of the car. It does it when the engine is running, in P, D, N, or R. It doesnt matter if the hood and / or trunk are open or closed. It appears to be connected to engine RPMs because once you rev the engine it "goes away" meaning you cant distinguish it any more, but I'm sure its still there.... its now just turned into a constant noise.

We have had the car up on a ramp, running, with a stethoscope everywhere and we cant find anything. Also we checked underneath for exhaust knocks, etc, etc and cant find anything.

This is going to to be one of those "If you've had it before you'll know it exactly" posts........so what do you think?

Hope everyone is well.

 

Hi Sarc,

You don't mention the year and engine of your XJ40, which might make a difference.

If your car is an earlier one, say 1988-89, then a known issue is hardening of the fuel line at the inlet end of the fuel rail (near the firewall). There is a small circular metal damper mounted in the fuel line, and as the line hardens with age it causes a "helicopter" sound that is only audible in the passenger compartment, though on our '88 it sounded more like it was coming from the dash. Replacing the fuel line solves the problem.

Since your sound seems to be coming from the rear, the first thing that comes to mind would be the fuel pump. If you have an '88-'89, it's an external pump mounted on the rear suspension. There is a check valve between the fuel pump and fuel filter that could potentially make noise. If your car is a '90-'94 the pump is in the fuel tank. On the '90-'92 cars you could check for pump noise by touching your stethoscope probe to the tank itself, which is accessible behind the trunk bulkhead carpeted trim. On the later cars, '93-'94, the fuel filler neck is a rigid metal pipe welded to the tank, so you could just touch your probe to the fuel filler neck.

Since you've been trying to track down a noise I assume you've had the radio off, but just in case, there are a few radio suppression capacitors in the system that go bad over time and allow ignition noise interference (RFI) that can cause pulsing noises through the radio speakers. No offense intended by suggesting this, but it's been known to happen.

Hopefully others will have more ideas.

Cheers,

Don

 

Hi Don

Its a 90 US Spec 4.0 XJ6. The details are in my signature....... but I just realised signatures don't seem to show up when using a mobile device, oops.

Some good ideas that I will defenitely follow up on. I was thinking fuel pump, although (with the help of a trusted friend) I got into the trunk and closed it and I couldnt hear the noise in there. Not sure if its relevant but my car is still running the adjustable rear shocks......

Yes, noise is still there with the radio off.

Just to give an idea of how subtle it is, if i run the fan on medium it drowns the drumming noise out. If the fan is on low or off its audible

If it stops raining I'll go do some more investigating

Thanks again

 

Hi Sarc,

Just for grins, you might try touching your stethoscope probe to the circular metal damper on the fuel line at the firewall end of the fuel rail in the engine bay just to see if the pulsing sound is at all similar to what you're hearing in the passenger compartment. Off the top of my head, I think fuel line "helicopter" sound was cured by the '90 MY, but perhaps not.

Also, it might be worth checking the condition of your rear engine mount/transmission mount. Typically noise from that area is heard in the center console near or just behind the driver's seat. There may be a heat shield there that the transmission can come into contact with, though I think if that were your problem you'd hear the noise even louder while driving.

Please keep us informed!

Cheers,

Don

 

Hi Don

I spent some time outside today with the stethoscope and a helper holding the car in D while I listened.

In summary, I am getting the sound exactly where you suspected. I can hear the noise through the stethoscope on the circular metal damper. I can hear it in the coupling down in the chassis leg where the fuel lines go down under the car. I can even hear it on the coupling in the fuel line right at the rear of the car before the fuel pump (My car has an external fuel pump underneath the car). I don't hear anything on the line that goes to the fuel filter. I don't hear anything from the fuel pump itself....... it just has a loud whirring noise. I don't hear anything on the engine block itself. I can hear it on the metal fuel line just before the fuel regulator on the front of the engine.

Now that I think about it, "helicopter chopping sound" is a pretty good description of the noise. It is a pulsing type of noise.

The loudest I can hear it inside the car is if I put my head down into the left rear footwell. It sounds really bad down there. If it's the whole fuel line thats pulsing I guess that why its noisy in the footwells..... ?

This car has had very little work done on it due to its low miles, so I believe all the fuel lines are original.

If I take the plunge, which lines do I have to change ? Just the ones in the engine bay?

For my own understanding, do you know what is actually happening to cause the noise ? And do you know what they changed in the revised fuel lines to stop the noise ?

Thanks for the help so far.... I think we are getting closer.....

Scott

 

This was as much info as I could find.....

91jaguar05
19-17
Fuel Rail Feed Hose - Knock
Noise at Idle
MODEL 88 - 91 MY Sedan DATE 8/91
ISSUE:
The fuel rail feed hose damper can harden resulting in a knocking noise from the dashboard area when the engine is idling.
ACTION:
Replace the fuel rail feed hose assembly. Use the procedure provided in the XJ6 Service Manual section 19.40.60.
NOTE: Do not replace the return hose.
WARRANTY INFORMATION:
Fault Code: 2HFF
Repair Operation Number: 19.40.60 (Fuel rail feed hose knocking-replace hose).
Time Allowance: 0.40 hrs.

 

That's it!

You only need to replace the feed hose.

According to the Electronic Parts Catalog (EPC), which you can download from this forum and install on your computer, the part number for that feed hose was EBC10330. Here's the diagram snipped from the "Fuel Filter and Return Pipe" page. The feed hose is Part 5 in the diagram:






You can also look up parts at jaguarclassicparts.com, the parts service of the Jaguar Diamler Heritage Trust:

Fuel Filter and Return Pipe - Parts For XJ6 & XJ12 from (V)667829 to (V)708757 | Jaguar Heritage Parts UK


Searching that part number EBC10330 at jaguarmerriamparts.com, the online discount sales service of the Jaguar dealer in Merriam, Kansas, I expected to find a supersession number, but that part number shows up as valid and still available at $117.72:

1991 Jaguar XJ6 Parts - Jaguar Parts Center - Call (800) 510-1401 for Genuine Jaguar Parts and Accessories


Cheers,

Don

 

Ordered........ fingers crossed. Will report back once its on!

 

Looking at that, I am slightly worried that the part EBC10330 is for the later, battery in boot, XJ40. Isn't the earlier for 3.6 litre cars part CBC2581 superseding to EBC9811?

Fuel Pipes-2.9/3.6 Litre - Parts For XJ6 (2.9, 3.2, 3.6, 4.0) from (V)500001 to (V)667828 | Jaguar Heritage Parts UK


I have a horrible feeling that though these pipes are very similar, the connector to the under body fuel line is different - a threaded joint on the 3.6, and a Legris connector on the later fuel feed pipe.

Here is a picture of the earlier EBC9811. Note the connector where it joins the under floor fuel line, low down:


1991 Jaguar XJ6 Parts - Jaguar Parts Center - Call (800) 510-1401 for Genuine Jaguar Parts and Accessories

And the later EBC10330, with Legris push fix connector:



Close up of the Legris connector:

 

Hi db in uk,

Sarc's car is a '90 4.0L. I'm not sure which part number he should have ordered, but hopefully the vendor he ordered from will ship him the correct part.

Thanks for the photos, by the way. Did you just happen to have these hoses lying around so you could photograph them?

Cheers,

Don

 

I think the changeover came at VIN 629286, from a look at the JDHT site here: Fuel Filter and Return Pipe-3.2/4.0 Litre - Parts For XJ6 (2.9, 3.2, 3.6, 4.0) from (V)500001 to (V)667828 | Jaguar Heritage Parts UK

They list the EBC9811 for the early 4 litre:

Fuel Pipes-2.9/4.0 Litre - Parts For XJ6 (2.9, 3.2, 3.6, 4.0) from (V)500001 to (V)667828 | Jaguar Heritage Parts UK

It could be I am not correct - and as you say, the parts company should check that the part is correct for the VIN range/model year in any event. Jaguar really do know how to make these things completely opaque, don't they!

I had the later pipe with the Legris fitting lying around, but stole the image of the EBC9811 from here:EBC9811 - Fuel Hose, GENUINE JAGUAR XJ40, Feed, With Damper | eBay

 

If Sarc ordered the hose from jaguarmerriamparts.com, they do insist on the VIN to ensure correct fitment, so he should be fine, assuming those opaque Jaguar records you mention don't come into play! We'll keep our fingers crossed.

 

It looks like I need the EBC9811, judging from my VIN and the fitting.

No new ones available that I can find........ Jagbits have a used one but I guess its hit or miss whether it will be quiet or not..... probably no way to know unless the hose is fitted to a car. I may give them a call tomorrow to discuss and see if they'll let me buy it but give me a refund if it turns out to be noisy.

What does the damper actually do? Based on the connectors, Im pretty sure I could get a hose made up sans damper....Just thinking of the alternatives.......

 

The used ones we sell usually are quiet it is a very old hose though...we give a 90 day replacement warranty...call us in the morning 888-524-2487

 

It might be worth trying to replace only the rubber section of your hose. My assumption is that it is the hardening of the hose that "amplifies" the sound of the damper and carries the sound to the metal sections of fuel line that mount directly to the underside of the body, transmitting the sound into the passenger compartment. Replacing the hardened rubber hose with fresh soft rubber just might eliminate the transmission of the pulses into the cabin.

Cheers,

Don

 

@Gary

Thanks for following this thread.

I ordered the part EBC9811-USED from your website. We will see if that solves my pulsing noise issue......

@Don

It's kind of interesting...... as it's a metal line that runs under the car I am imagining something like what happens when you get air in your water pipes...... the banging sound gets amplified, and it's also very hard to pinpoint where the noise is actually coming from as the whole pipe (or fuel line in my case) is vibrating.

 

Maybe its time to turn the radio on?


See sig.

 

The hose is here....... if it ever stops raining I'll fit it this weekend and post back

 

Fitted the hose...... noise gone, yay !

It's amazing how quiet the car actually is without the drumming noise.

Big thanks to Don B for the spot on diagnosis and Gary from Jagbits for supplying a quiet fuel hose.

Life with a quiet XJ40 is good.

 

Hi, My 1996 Jaguar XJ12, although I have replaced both Supply and Return Fuel Lines with used lines better shape than mine (new hoses I couldn't find), still make the same Helicopter noise, I am wondering if its possible to find these Fuel Line Dampers, which are shaped like round canisters in Black color? If so, does anybody know where to get these Dampers? Thanks !