Hi Everyone,

I'm needing some help here. I've been having some issues with idling/misfiring/vibration over the last 7 months, and unsurprisingly, the dealer is turning into a money pit with no results. So here I am, seeking the far superior knowledge of the forum.

So here's what my car is doing. It's a 2011 XJL Supercharged. I have 71,000 miles on it. Every time I start the car, regardless of whether it's a cold start or if I've been driving it and it's warmed up, I'll be greeted with one of three different idles and idle qualities. Here are three videos showing what's happening with each.

Idle 1: This is how idle should be and I'm sure what everyone here is familiar with on a regular basis (hopefully). It runs and feels smooth, and the engine is nice and quiet. Sitting in the car, you can hardly hear it running and can barely feel the NVH of the engine.

Idle 2: This is an idle that I frequently get. The engine emits a deep "exhaust throb" or "knock" that is clearly not present in the first video. The car tends to idle a little rough with this as well - it's not bad, but you can feel an occasional "skip" or "misfire". Sitting in the car, you can feel the rouger idle and hear the knock very clearly, like this: The car has always occasionally idled like this, and I've never thought much of it since it always seemed to be asymptomatic to the performance and driving experience.

Idle 3: This is the idle that has me the most concerned, and the one I've been noticing going back 7 months. It happens a little less frequently than idle 2, and sounds like the same "exhaust throb" or "knock" but with a rattle added in there as well for good measure. It almost sounds as though the engine is low on oil, even though the level fine. This tends to also produce the roughest idle - the "skips" and "misfires" are more frequent, and can be felt at certain RPM's while driving as well.

In addition to the sound of the 3 idles above, I'm also getting a vibration right in the 2,000 - 2,250 rpm range, pretty much right where the engine sits at highway speeds. Regardless of gear, the vibration is in that range. Even revving in neutral produces the same vibration. You can feel it in the steering wheel and seat. If the car starts with idle 1, the vibration is noticeable, but not too bothersome. If the car starts with idle 2 or 3, it becomes very pronounced and quite bothersome.

Now, I've been to the dealer 3-4 times for the idle and vibration issue over the last 6 months, and so far do not have a solution. The first time they heard idle 3 in the service bay, the reaction was "uh oh, that sounds like the motor. Is it low on oil?". They're check showed it was not low on oil whatsoever. They have replaced the fuel pump, propshaft, checked the coils and injectors, the supercharger coupler, and everything passes inspection. The most recent thing they did was the "performance pack" cleaning service, where they flush the fuel system, clean the intake, throttle body, etc. and said that it was due to a consistent misfire in cylinder 7. It ran better for about a month before this started up again.

I recently changed the oil to no avail as well. I change the oil every 10K miles religiously.

There seems to be no rhyme or reason as to which idle I get when I start the car, and I'm struggling to figure out which mechanical component could intermittently work or not work. I've heard mention of the supercharger coupler - I can imagine if it was bad, then it would consistently be problematic, not just sometimes. Same goes for the injectors. And the timing. If the timing components are going bad or have skipped some, they don't just decide to skip back to where they're supposed to be sometimes. It would be a constant issue. Also, I've shown no CEL's throughout any of this.

So the reason I'm seeking the forum's help is this: I'm tired of wasting time and money at the dealer when nothing is improving or getting better. Either the dealer is as stumped as me, or they're lying about the components that check out and the inspections that they've done.

Maybe one of you out there or one of our fearless techs has some advice as to what it might be? I'd like to go back in with a specific area of focus as opposed to this process of elimination that I'm stuck in. It's very frustrating and I'd like my car to just run smoothly the way that it used to.

Thanks in advance, and sorry for the novel of a post. Just trying to get all of the relevant information out there and hoping for the best.

 

I definitely experienced these noises on my 2010 5.0 V8 Supercharged XF, but I was never able to pin down what caused them, until my engine experienced fairly catastrophic failure (two spun rod bearings due to oil starvation that similarly I couldn't find the cause of), which I'm currently in the slow process of rebuilding.

I feel that in the past, people (including me!) have jumped to the Supercharger Isolator Spring as an explanation for any issue involving noises with this engine and while these springs can (and do) fail, they can't account for every bad noise people come across. The more I read up on this during my rebuild (especially in the Range Rover world), the more I'm convinced there's a more serious problem that has affected a number of our engines, maybe with timing, or oil supply - I'm not sure. The results can range from timing gear being replaced by the dealer to outright engine failure like mine. Presumably Jaguar NA has the data from all of this and maybe is aware of what the problem is, but I doubt we'd ever get that from them. I do know that there are two different pitches of timing chain on this 5.0 engine - 6.35mm and 8.0mm and these presumably changed at some point. but I don't know when this point was or why the change happened, which could've been something as simple as a different supplier being able to meet manufacturer demand.

You're right that timing gear doesn't just skip back to where they're supposed to be, so my suspicion is the sensors or actuators involved in the VVT setup (there's one for each cam), though you'd think if it was a sensor this would throw a CEL.

If you find an answer to this, especially as I'm in the process of rebuilding the engine after an engine failure that happened after experiencing those same noises (which in fairness may or may not be connected) I'd love to hear

 

BTW, I thought this was rather interesting.

 

Thanks for the info, Dave. The thread you posted explains the knock, but what stresses me out is the rattling noise that makes it sound like it's low on oil.

There's a lot of threads on the forums here that seem to point to timing, but I'm not convinced that's what it is due to it's intermittent nature.

 

Well, my 5.0 ceased and I am clueless why. I agree with Dave after reading more and more of these posts that there's something not right with this engine. Jaguar may know - but we certainly don't....how many others have this problem(s) that don't visit the forum(s).

 

I agree that the supercharger coupler is either good or bad, and noises would not be intermittent. I also agree - to an extent - the same with the injectors, though I think intermittent issues are surely possible with an injector that is in the process of failing.

However, I've thought about this and I disagree that an intermittent issue couldn't be caused by timing. Traditional fixed mechanical timing, yes - but these engines have variable valve timing controlled by electrical solenoids (one per camshaft) supported by camshaft position sensors (again, one per camshaft). I think if one or more of these components (most likely the solenoids) were to start failing or had an intermittent fault, it certainly could manifest in an intermittent noise at idle. Incidentally, the VCT (variable camshaft timing) units are also dependent on an oil supply which comes from the camshaft bearing.

I've attached some Jag training info with information on the VCT units.

 

Something that I feel adds further weight to this theory is if you search youtube for VCT issues with F150s, you'll find videos demonstrating problems that sound an awful lot like yours: for example and .

Apparently these problems have been well known by the Ford guys for ages.

 

This idle issue is also on the naturally aspirated engines too. The other problem is the shaking engine tears up the hydraulic motor mounts & tranny mounts.

 

We have a 2010 Land Rover Range Rover HSE that shares the NA 5.0 L with Jaguar. I assume Land Rover did some tweaking to the motor, but basically same as in a XJ or XF. We bought it when it had 45,000 miles, now has 90,000. Never have I heard an abnormal noise or slightest vibration in the cabin at any speed. It has always idled smooth as glass. I wish I could say that about my XJ with supercharged V6!

I think LR uses beefier isolation, i.e., motor and tranny mounts and perhaps a more robust valvetrain. The 5.0 L (and 3.0 L) engine is really a sweetheart when sorted. It's too bad so many are having issues

 

This is useful information, as it means you can likely rule out the problem being down to the supercharger. The naturally aspirated engines share the same VCT setup that the s/c models do (though they additionally have Camshaft Profile Switching).

 

IMHO its one or more of the variable timing modules located at the front of each camshaft. I had one on the right exhaust camshaft that went bad and it resulted in a similar symptom as you are experiencing

 

If it is a low oil pressure issue, maybe the idle rpm is dropping too much at idle. Could be a software fix? Raise the idle rpm a little, increase the oil pressure?

 

Hey guys,

So I dropped my car off on Friday for the inspection. I took it to a different local Jaguar dealer and plead my case regarding the bad experiences I had with the other dealer. They gave my car to their "master tech" with 20 years experience (a little schmoozing goes a long way!).

I get a call Friday afternoon with an update. Their master tech feels that it's an injection issue and that all of the issues are attributed to the "obvious misfire". They said there aren't and codes stored, but of all the engines he's seen, mine has all the signs and symptoms of a dirty or clogged up injector that's inducing the misfire. He said everything else on the vehicle checks out and that a proper cleaning should do the trick.

What was interesting is that he said the way he performs the cleaning procedure is different than what the manual calls for, but says 99% of the time it will take care of any idle/misfire/injector type issues. The manual calls for a cleaning process of idling the engine for 20 minutes with the cleaner in the system. His process is to run the engine with the cleaner for 10 minutes, pressurize the system with cleaner and leave it sit for 10 minutes, then run the engine with the cleaner for another 10 minutes.

Fingers crossed that this works. I'm pretty pissed I'll be out another $400, but they wanted to keep the car until Monday (today) to make sure it resolved the issue. I haven't heard from them yet, which has me a little worried, but I'll be cautiously optimistic.

I'll make sure they check the VCT as well - thanks for posting those videos!

 

I sometimes have Idle#2 on my normally aspirated 5.0 at under 40k miles.

The VCT comments make me wonder if this motor suffers from the same issue as the Maserati 4.2 engine. If it's driven gently all the time, the variable cam system rarely operates and it gets sticky and unpredictable when finally called on.

 

@a6kmita


curious whether the injector cleaning job did solve the problem .


regards
Ulrich

 

Ulrich, unfortunately it did not. Dealer recommended "starting" with replacing the injectors for $3,500 since they weren't sure which one may be the problem.

I just sold the vehicle on Thursday - what a sad day! I miss it like crazy already, but have a little solace in no longer having to worry about any of the issues I was experiencing and trying to hunt down a fix. The thing that helped me really make up my mind was that the dealer couldn't definitively say whether the strange idles were injector related or oil related. That scared me! I had some other issues creeping up as well, so my checkbook is sighing with relief about now. (Slow/delayed shift from 4th to 5th, suspension creak/rattle they couldn't find, corroding chrome wheels, and of course the vibration and strange idles I was experiencing).

I'll get get another one some day, but for now I'll have to be satisfied putting miles on the Chrysler 300C John Varvatos AWD I picked up.

I still look forward to being a very active member of this forum! I appreciate all of the responses to this thread and others I've subscribed to and look forward to helping others troubleshoot and celebrate their beautiful vehicles. Appreciate that torque, because you'll miss it once it's gone!

 

My bet is your timing chain tensioner and or chain guide is bad. On cars with knock sensors a loose timing chain can throw a misfire code, it also would explain the different sounds on the same issue

 

M 2011 XJL Supercharged has some of the same idles. At 53K miles. I too thought it sounded like a low on oil sound, but the dealer in Atlanta just serviced the car and said that they did not hear anything that sounded like what I was describing to them. Kinda irked me a bit because I know the sound is there. They may just see (or hear) this as normal, but it still sounds off to me. I have no performance issues during driving or acceleration, but the knocking and rough idle are definitely there. As with my previous BMW's of my MB S50 I traded for this car, getting someone to admit there is a common issue is an uphill battle. Yet on the forums for all of these cars, there is proof! SMH!

 

I just bought a 2011 XJL SC, 60k miles, Got a steep discount at wholesale as the car made this same noise at idle, among other issues, bad window, inoperable sunroof, roof pop, blown speakers, bad brakes, etc. But the car looks absolutely brand new so I'm OK with repairing, and will still come out way ahead.
Anyway, it has the identical sounds as in your video, and acts up at idle intermittently exactly as you described. I took the car to Sonsini's in Philadelphia, they work on Ferrari, Jaguar, and other exotics and I have known the owner for a long time, 20 yrs. SO I definitely trust him.
So I took my car in today, and knew exactly what was wrong. He also said he double checked simply by putting his finger in the oil filler opening and lifting on the timing chain. He assured me car will idle like a purring kitten when done. They are removing and replacing vvt timing chain, gears, tensioners, solenoids, seals and guides.

And he said the reason the car runs like a champ under throttle is that the timing chain is pulled down under load, and it is pulled tight while giving throttle so its running perfectly. He also said if I had driven it around like this for another 5,000 miles or so. I would absolutely blow the motor. said even at idle the timing being slightly off can cause the valves to bend a bit and then your fubar. and as the problem gets worse I would have started to get random misfires diving it around.

So Ill keep you posted as to the repair and hopefully this fixes it. its costing 4k $$ even as a long term customer, so if all this work doesn't fix it, Ill just go cry in the corner...

Good Luck.

 

Thought I replied to this earlier, but I am new to this forum and I guess it didn't post so I'll reply again. I also have a new to me jag 2011 sc. it had the identical distinct noises you posted on your video. And it's intermittent in the same manner. Anyway, I took it to a trusted high end import mechanic in Philly that I have know for a very long time and he knew right away just by listening, and by moving the timing chain around with his finger inside the oil filler opening. Said it was unmistakable.

He said it's a bad timing chain set up. So we are doing all new gears, seals, chain, tensioners. Solenoids, and guides. Basically a complete rebuild of timing chain and components. Also said the reason the car still runs perfectly besides idle is the tensions are corrected as soon as the engine revs and the chain is pulled taught. And that if I had kept driving like this I could easily of basically blown the motor. He said when it's really bad it will start to backfire a lot as well, and at that point you have to address the issue. And apparently all the parts have been updated with newer versions and will last much longer without any issues.

Anyway, just thought I'd share my experience and I'll repost when I get the car back, and I'm praying this will fix the issue as when it bad, it's really bad, and almost embarrassing.

Chris