Perhaps another instance that the American saying: 'If it ain't broke, don't fix it!' can apply to...

 

Incorrect again. You most certainly can hear it and yes the knock sensors are on top of it but we must be at the maximum edge of timing to achieve the most efficient combustion and max power.


You can even monitor the output of the knock sensors so you can see at what RPM's and loads the most pinging occurs. Kinda cool to see. I use the ScanXL software.
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Thanks everybody for the replies, they are very much appreciated.

tbird6: Thank you for confirming I'm not crazy! My girlfriend can hear it in the car but it isn't easy to hear in the recording. Are you using the standard ScanXL or ScanXL Pro? What kind of interface are you using, USB?



I was actually going on the information on one of your other posts on the spark plug thread...
I thought the engine might be pinging (detonation or pre-ignition). I was under the impression that both sound similar. However, after learning that the knock sensor would either do its job or throw a code, I am starting to look elsewhere.

I do have an OBD scanner that can read live fuel trims among other data. Is there anything I should be looking for? I have readings for the timing advance at 2000 RPM (35 degrees) and 3000 RPM (44.5 degrees). It sits at 5 degrees during idle.

Any other common rattles under load? Maybe a belt?

 

Note that I mentioned only pre-ignition in my post, not detonation. Many people use the terms 'pre-ignition' and 'detonation' interchangeably. They are NOT the same thing at all.

Detonation = pinging, pinking.

Pre-ignition= run-on, dieseling.

The former is a combustion event that starts off normally at the correct interval (spark) but degrades into a spontaneous explosion (detonation) of the remaining air and fuel. Insufficient octane and or excessive ignition advance are two common contributors.

The latter is as the name suggests. The fuel/air combusts normally but not at the correct interval (spark), in other words occurs before the plug actually fires. The common cause can be too hot a spark plug tip or hot spots in the combustion chamber.

Contrary to the post above, it is not desirable or typical for engines to have ignition timing right on the ragged edge of detonation. A common but incorrect assumption is that more timing equals more power. This is simply not true as an overly advanced spark will actually cause the combustion chamber pressure to rise before the piston has reached the top of it's stroke. The effect is that engine output decreases in this condition as the combustion pressure is now trying to push the piston back against itself.

All engines have a demonstrable limit at which more timing reduces, not increases power. Taking the venerable Chev small block, this is generally between 36-38* BTDC under WOT condition at high RPM. I get a laugh at the boy racers trying to go beyond that by putting 100+ octane fuel in the car to quell the detonation.

It is also NOT normal to hear detonation on a modern car equipped with knock sensors. If you can hear it, the sensors have not done their job.

 

Update. I changed the plugs for a set of colder ones (NGK 6418 BKR6EIX) and swapped out the coils for some lightly used ones. The pinging/rattle is still there and maybe a bit worse. I noticed oil in the wells and took some pics using a borescope...



front drivers side 3 photos...









front-mid driver's side











rear-mid driver's side








I didn't take pics of the rear driver's side but the plug wasn't full of oil




front passenger side...











front-mid passenger side....











rear-mid passenger side













rear passenger side








I think the gasket work is above my head so does anybody know what parts I should be looking at replacing?

 

If you can't do it then whoever does will just look them up.

 

JagV8: I was mainly interested in getting a rough idea of how much this might cost. I don't want to be surprised with a $ 2,000 bill.

One more note, I made another video of the sound in the hopes that someone can identify what it is. The rattle is audible through my laptop usb speaker at 12 secs and again at 14 secs when I blip the throttle. The rattle seems to disappear under full throttle and is intermittent under partial throttle....




I am going to take the car to the mechanic's on Thursday/Friday. If anyone has any suggestions please sound them out, I was looking at Coventry Jag and The British Garage.

 

If nothing else, your pics showing nice clean combustion chambers will serve to demonstrate that periodic engine cleaning to remove supposed carbon deposits is not required.

I heard nothing in the video that sounds like detonation, nor would revving the engine in neutral induce it.

 

Mikey- I was in gear in the video. Revving in neutral doesn't produce the noise.

With the assurance of the knock sensor, where else to look? Pulley? Tranny?
the guys at The British Garage didn't seem to think it was anything other than pinging which was normal but this really concerns me.

 

I ***-u-me-d that the quick revving of the engine without the car going much faster indicated that the trans. was in neutral. Might be better if you had someone hold the camera pointing at the gauges while you demonstrate the problem.

Which yellow warning lamp is on?

 

No worries. The airbag light is on (passenger sensor).

I will try to get some better video. the RPMs aren't rapidly rising but do increase appropriately with speed, the car just feels a bit sluggish and hesitant to upshift at less than 20-30% throttle, (perhaps heatsoak?).

 

I can hear the pinging on the video and it sounds exactly the same as in my STR under the same conditions that you describe. It is summer with 37-40 Celsius here in Spain but I'm not sure if it happened in winter also.

I had half a tank of 95Ron and I filled it up to full with 98ron to see if it improved but was the same.

The car has only 52000km (32200 miles) and has just being serviced by Jaguar (oil, oil filters, etc).

If I put it in sport it seems to go away. Also I did a ECU reset (hardboot: ignition off, disconnect battery negative, ignition in position 2, touch negative to positive, ignition off, reconnect battery). After the reset the gearbox was changing earlier and no pinging but after a 300km journey at "legal" speeds (131km/h just before road radars triggers, @2000rpm) the gearbox went back to high gears on low speed and pinging also back.

Previously I had an Stype V6 and no pinging noise. Is this noise really "normal" on STRs? There seem to be a few entries on Internet from different owners, and may be not all owners hear it because you need to be with your radio off and even the A/C in "mute" to hear it.

That pinging is really anoying me as it makes me think that it is damaging the engine.

 

i know your km's are low but i wonder if in the past or even still your catalytic converters have been compromised by a vacuum leak or fuel deficiency ?
start by checking your fuel trims with a scanner that should lead you in a specific direction , and throw in a new fuel filter and check and replace if necessary your spark plugs and clean your MAF sensor . I've just been through all this with mine and shore found some leaks in the intakes and the common brake booster vacuum fitting on the intake neck also .
that probably killed my cats but they were already pretty much cooked when i purchased my STR. and after all that i still had pinging!
this is were i ended up after trying most other go to's to get my fuel trims back on track. and put a stop to my pinging.-

https://www.jaguarforums.com/forum/s...r-cats-165848/

and

https://www.jaguarforums.com/forum/x...solved-137070/

 

Many thanks for your response. I've been reading for more than two hours those two posts (they are huge) trying to understand them.

I'm sorry but I'm new to this and I don't know a lot about the terminology, appart from the fact that my native language is Spanish. What is WOT? Fuel trims are fuel pressure measured by the scan tool? I have an ELM327 bluetooth, recomended program? is it possible to get the special Jag codes?

I don't think sparkplugs have been changed within the normal Jag services with just 32k miles. Should I change them just in case or would it be a waste of money for such low milage, I read that they are usually changed at 100k?

The first time that I read the codes with the ELM327 on 23 jul. I got a P1111 "Intake Air Temperature (IAT) Sensor Circuit Intermittent High Voltage." but I have not received that code again and the dealer didn't mention anything when they did the service. Could that be the source of the problem? Do you know how to fix that? Would cleaning fix it? Any post about how to cleant it?

How do I check for intake leaks?

One thing that I just remembered is that when I purchased the STR with only 15k miles the first time that I floored it there was black smoke coming out of the exahust. I saw it through the center mirror... then never again any kind of smoke. The previous owner told me that he never went past 120km/h... so I assumed that the engine was dirty from not pushing it and that I just cleaned it up. May be that killed the cats also?

I was planning to get a Varex mufflers from Australia with remote controlled electric straight valve (Varex Mufflers and video of stype ) but may be I first get a 200cell cat and later the mufflers...

I'm sorry that I ask so many things but I'm knew and the forum is huge, a little bit of guidance so I learn would be much appreciated

 

P1111 does NOT mean that. Either search on here or download the free codes / workshop manual.

Acronyms see below

 

I don't think we've ever see a bona fide case of detonation on an S-type, irrespective of engine option. It seems some -R models, but not all, produce a slight clattering sound, but all conventional methods of treating detonation have failed- inferring that it's not actually detonation.

I don't know of any engine that has suffered any damage from operating in this condition over a prolonged period.

 

What smart phone/tablet do you use ? Bluetooth is no good for Apple .
I use these apps (obd car doctor) and (dash command).

Most or all the info you need is in stickys at top of s type forum !

 

Is this the case? My XJ did it bad until I found a vacuum leak, but I still get random hints of it, but it is barely noticeable most of the time.

 

Thanks for the queue, yes, you are right P1111 this is what I found in the forum ( https://www.jaguarforums.com/forum/x...e-p1111-36127/ )
"P1111 is not a fault code. It is a special designator Jaguar uses meaning system ready, drive cycles completed after the last fault event. P1000, on the other hand, means system not ready, or drive cycles not completed after the last recorded fault event."

So it seems that no problem with the MAF then!

 

That would be a big relieve if confirmed, but Datsports apparently solved his detonation or clattering by fixing air leaks and replacing the cats with 100 cells ones. Or so I think to understand from his posts...

You hit the nail on what makes me nervous, the car apparently runs ok, it feels powerfull and I'm used to powerful cars, if it had less than 350hp I'm sure I'll have noticed, it's just that clattering noise that makes me feel that the engine is suffering (rods, etc) and that will cause a huge repair bill later on.

If it is "normal" on this engine, what could be causing it?