Under light to moderate throttle, right around 2500-3500 RPM, I can hear a rattling sound from the engine bay. If I didn't know better I'd say the engine was knocking.

I've heard that the injectors can chatter a bit. Is this what I'm hearing?

Cheers,

- Will

 

Talked to the service manager at the local dealership. She said the noise is from the 'secondary air intake' and chatters between right around 3000 RPM (gave the exact range, all I can remember was the lower number was 2700 RPM and the upper was 3500 RPM or so...). Makes sense with what I'm hearing and the RPM range...

Cheers,

- Will

 

I definitely need your help with this. This has been plaguing my car since I first bought it in January 2010. Did they tell you whether this can be repaired? I started a few threads on this, and nobody has been able to identify it. You finally nailed it spot on. Please give me as many details as possible.

 

XFactor -

Unfortunately it is a feature of the secondary air intake on the XFR (and perhaps other cars in the lineup?). Apparently as the intake goes from closed to full open, it chatters at the intermittent period starting at 2700 RPM.

The service manager knew what I was talking about immediately so I'm pretty satisfied by the answer.

Someone else had posted in another thread how they preferred the sound of the naturally aspirated XFs in the cabin. Having owned my car over a week now I have to agree. The base models sound so so sweet with a little gas. The SC models sound good, but having heard the base models I miss their chorus!

Cheers,

- Will

 

Thanks for your quick response. Unfortunately, I'm not completely buying it. Here is the reason why:

When I first brought my car into my dealer, they looked at it probably about a half dozen times. Got the shop foreman involved, and they called Jaguar. They were told that it is a result of the fuel pumps which are loud. They hooked up, what I guess were microphones to the car, and they determined that it was the fuel pumps.

I'm not fully buying it, because every answer they want to give is that it is just a feature of the engine. But, here is the truth of it. You cannot hear the sound on cold start. So, if you run your car upon your first start, I challenge you to hear it. The only time is when there has been a substantial amount of heat soak in the engine. It is very strange.

Also, to a small degree, I find that different types of gasoline affect how pronounced the sound is.

Finally, if this is completely normal, I think anybody who has an XKR or any other supercharged 5.0 s/c would hear this. I have driven a lot of these cars at R performance academy, and other Jaguar events. I also test drove the XKR-S, and they do not have the sound whatsoever.

One other point: I noticed that you also have the 2010 XFR, which is exactly what I have. I wonder, if at some point, they discovered how to resolve this issue during production after the first year.

 

Both those comments would be a feature of pinging/knocking, which could be fixed rather easily with an ECU tune and would explain why only the first model year displays it and only occurs in a certain part of the operating range until particular throttle conditions.

Not saying it is knocking, just a possibility that fits...

Cheers,

- Will

 

I have nearly 6k miles on my 2012 S/C and have never heard the sound that has been described in the previous posts.

 

2010 SC and no such noise.
I do get abrupt change from quiet to loud in the cabin on large throttle application. I wonder if the chatter is the active sound channel opening. Supposed to be a feature but perhaps yours is acting up? Is it under hard throttle application?

 

Hard throttle no. Light to moderate throttle yes. Steady RPM (i.e. not accelerating) at 3000 RPM no.

Also using paddle shifter yesterday I noticed it does not go away at 3500 RPM like I originally thought... I can hear it until it eventually gets drowned out by engine/road noise above 4000 RPM.

Cheers,

- Will

 

Are you sure it's not pinging.

 

No not at all. I haven't ruled anything out.

Light pinging under moderate throttle would certainly fit the symptoms to date, and to my ear that certainly sounds like what's going on. But I can also see how it would be caused by chatter in the injectors or an air intake. I would have expected that a supercharged direct injection engine of this caliber would have anti-knock sensors...

How is the timing set on this engine? I would be interested in retarding it slightly to see if that affects the rattle at all.

Cheers,

- Will

 

I've heard a similar noise

I hear a ticking noise during full throttle. Didn't sound like pinging but Jaguar did the following bulletin JTB00241NAS1. The car still makes the ticking noise. I dyno'd the car and the AFR ran ~14 at idle but dropped to 9-10 during each of the pulls. I would think the rich condition would help pinging.

Jaguar Bulletin.pdf

Almost sounds like the A/C fan.

I'm going to try and see if I can locate the noise when the car is in park. If it is the secondary air intake I should still hear the ticking.

Next effort will be to take it to an independent mechanic.

 

Run higher octane Fuel see if it goes away, something like 100 octane.

What is premium rated at in your state, we get 91 octane. NOS has an octane booster that is supposed to give 6 more points its about $15. I used to run it at the track when I ran Nitrous for a little extra protection against detenation.

 

I always run it with 93 octane. I don't even know where I could find 91 octane around here. It just goes 87, 89, and 93.

Personally I don't believe the Octane boosters. Not trying to start a divergent thread on the subject, but the physics just don't make sense.

I'm fairly convinced it's not pinging in my case. It comes on quickly after startup and seems persistent regardless of the engine temperature. I do think it is probably injectors or something related to the intake system.

Cheers,

- Will

 

100 octane unleaded is at a few pumps in Phoenix otherwise 91 is our premium fuel's rating :-(

 

Just added some Lucas fuel injector cleaner to the car, we'll see if it helps the noise. We're also seeing cooler temps in Houston this weekend and this would also help lower the chance of pinging.

BTW - I always run 93 in the car but I know a speed shop that has some 100 that I can test out.

I just want to make sure it's not an engine issue before I do an ECU tune.

Dreaming of XFR power for Christmas out of my XF SC.

 

If the first ingredient in your octane booster is MMT I would believe in it if its not then they probably don't increase the octane. Methylcyclopentadienyl manganese tricarbonyl - Wikipedia, the free encyclopedia

Now whether or not there is a performance gain from higher octane is debatable. On a car with a poweradder (supercharger, nitrous, turbo) higher octane should = more power. NA cars probably nothing.

the first ingredient in NOS octane booster is MMT it works.

 

The problem is that this pinging sound occurs on partial throttle between 2500 RPM and 3500 RPM. I do agree that it sometimes is evident all the way up through the rev range. Either way it usually happens when there is some heat soak evident in the engine. I simply do not hear it when the engine is cooler upon first run in the morning. I also find that it is worse on humid days, than on cool dry days.

This pinging sound has been plaguing my car since about 6000 miles. I have 63,000 miles on the car now. In the beginning, I had my dealer troubleshoot every possible source of the sound. Ultimately, they concluded it was the fuel pumps that are noisy, and the sound becomes evident on partial throttle...

I simply do not know if this is accurate because you would hear it in all of the other supercharged cars. I have driven everything from the XJ supersport and the XKR-S, and I've not heard this noise. I have driven other XFRs during the R performance academy, and never heard this pinging. Another point is that I just got a Mina exhaust, and the inside of the tips are caked in black soot after running about a week or two. Therefore, I suspect maybe the engine is running rich which may revert our analysis back to the source of the pinging sound.

Lastly, I wonder if the ethanol has anything to do with this. I know that every gas station here in New Jersey says they have 10 percent ethanol in their gas mixture. Could that be causing the sound on some of the earlier models of the 5 L supercharged engines?

If anybody can solve this issue, I think that they would be a hero.

 

My 2010 XF SC seems to have stopped making the rattling/pinging at 2500-3000 rpm. I’ve put in Lucas fuel injector cleaner for two tanks. We’ve also had cooler weather in Houston this week but it got up to 82 degrees and I didn’t hear any noise like I used to at these temperatures.
BTW – My earlier post listed Service Bulletin JTB00241NAS1 which deals with pinging. The Jaguar fix is to add BG 44K Fuel Additive. I’m going to order some online as I couldn’t find any locally – hence the Lucas fuel injector cleaner.
I’d recommend getting two bottle of the BG additive and see if it helps.
Might also open the pdf to get the exact Jaguar verbiage on what they did to my car.

 

BG Findashop - Search for an authorized BG service center near you!

Link above will help you find some locally. I'm going to pick some up from the local Mazda dealer.