I have received a lot of requests for this info so here it is.

I bought my knock sensor on Ebay for $28: http://www.ebay.com/itm/AIRTEX-5S561...d65ea1&vxp=mtr

I decided to relocate the left side knock sensor on my 01XJR rather than try to R&R the supercharger.

I left the old one in place, plugged the new on into the wiring harness and attached it between the intercooler and the supercharger body. I used heavy duty zip ties and heavy duty epoxy to secure it. (I know, but it worked)

I have put about 500 miles on my car with no problems and no codes.

I always use 93 octane premium and I live in Florida so no high altitude or mountain driving for me. I still have the right side sensor in the original location and I think the chances of me having any serious engine knock that would not be detected are pretty slim.

This mod is not for you guys who have told me that you can R&R a supercharger in 5 minutes while sipping a glass of port, its for those of us with limited mechanical experience who don't want to get into a two or three day project.

If you want to debate the wisdom of this mod, please start your own thread.

User assumes all risks and YMMV.
Vector

 

Hey Vector....nothing like a bit of latteral thinking outside the box.
Considering they are a piezo electric device it stands to reason that it can be mounted anywhere as long as it's close enough to detect the knocking in the combustion chamber and at the same time make life a bit easier ;o)

 

Glad it worked - I could see no logical reason why it shouldn't.
Aluminium's a pretty good conductor of sound and the signal to noise ration the sensor's looking for is pretty big.
Even as a temporary fix until the day you HAVE to pull the S/C off it seems pretty good.
How did you cope with the connector? Presumably the original is still plugged into the defunct KS.
Into the HOW-TOs.

 

Any chance you can post a picture and details of cut/ splice if done. Would lke to do my 2001 XJR th same way.

txs

 

Sorry I'm still not awake and missed picture !
Looks great

 

Fantastic, this is exactly what i was looking for! Clever, very clever indeed.

 

Have been playing withexternal knock sensors (i.e. not the OEM ones) to learn from, and knowingmore now, by relocating them you will alter the sensitivity. Not in the sensethat you will get error codes, but in the amplitude of certain signals ina certain frequency where the ECU has been calibrated for to identify a smallknock. This goes even to the cylinder where it occurred, and for thatparticular cylinder it will then pull the timing, and advance it over timeagain if the knocks do not occur anymore.

So I would not advice doingit this way, the knock sensor setup is there as an insurance if things go wrong,not something to tamper with imho.


Have been playing withexternal knock sensors (i.e. not the OEM ones) to learn from, and knowingmore now, by relocating them you will alter the sensitivity. Not in the sensethat you will get error codes, but in the amplitude of certain signals ina certain frequency where the ECU has been calibrated for to identify a smallknock. This goes even to the cylinder where it occurred, and for thatparticular cylinder it will then pull the timing, and advance it over timeagain if the knocks do not occur anymore.

So I would not advice doingit this way, the knock sensor setup is there as an insurance if things go wrong,not something to tamper with imho.

 

I believe the ECM autocalibrates.
It's difficult to get to the truth but I understand it listens to the background noise to set a 'no-knock' threshold.

 

No, the knock sensor is just a microphone, the ECU wouldn't know where to start autosensing... It is preset to listen to a certain frequency band and certain amplitude, and only if there certain thresholds are exceeded, it will react (and starts pulling timing for the cylinder it has identified).

 

I'll have a look round. I found a write-up on this some time ago when querying, yet again, the sanity of an 'engineer' who would re-use a convenient lug on the N/A engine for the S/C version knowing this meant paying $1000 to replace a $25 part.
The ECM definitely listens to background noise to see if the KS is working.
As I said in the previous post the easiest thing would be to put a dual trace scope on one installed in Jaguar's Silly Place and one glued to the head.

 

No, the new connector is plugged into the original harness connector for the knock sensor. The old knock sensor is unplugged. I'll post a pic to this thread when I can.
Vecor

 

Does it come with a flying lead then ?

 

Avos,
I resisted posting the details of this mod due to the controversy that it kicked up when I first proposed it. I only did so after receiving numerous requests for this info. There seem to be a lot of us out there who dread pulling the supercharger to replace a $25 part.

I think we can each evaluate the risks/benefits/savings of this mod based on our individual knowledge, mechanical ability and financial circumstances.

In the friendly nature of this forum, with all due respect do to you and understanding that you have a right to have your opinions heard, please read what I wrote in my original post:

"If you want to debate the wisdom of this mod, please start your own thread."

I started a thread about this mod some time ago and got NO RESPONSES to to it: https://www.jaguarforums.com/forum/x...sensors-90978/.

If you would like to comment in this manner, I very respectfully suggest that you go to the thread above and continue this debate or, as I requested, start your own thread.
Vector

 

Yes, it plugs right into the OEM lead on the engine.
Vector

 

Vector,
I'm thinking of closing this thread soon so it remains a useful HOW-TO.
I think you've set out your stall and we've had reasonable (although in my personal view probably unfounded) anxieties expressed.
I'm not suggesting this as a means of stifling criticism, just I sense you want to make a statement and be done with it.
Any thoughts?

 

@Vector,
If you can't prove me wrong, aren't you taking an uncalculated risk?

I have no stick in this, other than that I want to point you to a potential serious flaw in your setup.

You obviously want to ignore my input, that's fine, but I hope others will be a little bit more careful, so consider my post for them then.

 

I agree, I asked for some simple courtesy and didn't get it. Shut it down.
Vector