anyone had a knock sensor replaced?

[Guest]

hey looking at taking my car to subaru for a knock sensor

anyone had one done lately and how much did it set you back so ive got an idea of what the damage will be lol

[Bazza-NZ]

 SICNIS said:

hey looking at taking my car to subaru for a knock sensor

anyone had one done lately and how much did it set you back so ive got an idea of what the damage will be lol

They aren't too bad to replace so you can do it yourself and save the labour cost.

Not sure on the price of the sensor but i man have a spear around if you wanted to go that way?

[Dacca]

If you have CEL come on due to knock sensor,you can repostion it to top on intercooler,CEL goes away

[Guest]

i have CEL due to knock being cracked i found it lol thanks bro

bazza yeah bro could be keen and whats your labour charge for installing it,

i heard they had to be torqued up so not to keen on doing it myself for fear of having it to tight or to loose haha

[rico]

I did mine a couple of months ago, think it was about $90 new from subaru dealer. Replaced it myself, is a bit fiddly to get to the bolt but not that bad and only took me about an hour which isn't too bad since I had never removed the TMIC before.

Apparently its crucial to position the new knock sensor at the correct orientation/angle, I just took picture of old one in place then put new one as close to that as possible. Also don't have a tourqe wrench so just did the bolt up about as tight as it was when removed it.

So far all good and CEL hasn't returned, so I'm sure you could DIY if wanna save some cash.

[gazzy2000]

yup torque to 24NM and mount on a 60 degree angle from the front the car

clean the mounting surface, clean the bolt, reset ECU aftewards to clear any falsely learnt knock activity etc

[Bazza-NZ]

 gazzy2000 said:

yup torque to 24NM and mount on a 60 degree angle from the front the car

clean the mounting surface, clean the bolt, reset ECU aftewards to clear any falsely learnt knock activity etc

any reason for the 60 degree angle?

[Bazza-NZ]

 SICNIS said:

i have CEL due to knock being cracked i found it lol thanks bro

bazza yeah bro could be keen and whats your labour charge for installing it,

i heard they had to be torqued up so not to keen on doing it myself for fear of having it to tight or to loose haha

No charge for labour as long as you get your hands dirty

[gazzy2000]

 Bazza-NZ']

[quote name='gazzy2000 said:

yup torque to 24NM and mount on a 60 degree angle from the front the car

clean the mounting surface, clean the bolt, reset ECU aftewards to clear any falsely learnt knock activity etc

/quote]

any reason for the 60 degree angle?

*The sensor may be tuned by torquing the attachment bolt is the bolt is mechanically in parallel with the piezo crystal. If the bolt is too loose, or too tight, the centre frequency of the sensor can be incorrect, so the sensor might pickup the valve train noise rather than knocking electrical noise.

My oplogies the sensor tail/loom has to be 60 from the back of the engine i.e. replace the new one in the same position, maybe marke it before removal.

googling reveals that you can throw a CEL if the sensor is not at that angle. As for the pure science behind it i am unsure (still googling) but when i was digging deep into knock sensors a while back the best prcatices said 24NM and the 60 degree angle.

Torque setting QUOTE: *The sensor may be tuned by torquing the attachment bolt is the bolt is mechanically in parallel with the piezo crystal. If the bolt is too loose, or too tight, the centre frequency of the sensor can be incorrect, so the sensor might pickup the valve train noise rather than knocking electrical noise.

[gazzy2000]

 gazzy2000']

[quote name='gazzy2000 said:

yup torque to 24NM and mount on a 60 degree angle from the front the car

clean the mounting surface, clean the bolt, reset ECU aftewards to clear any falsely learnt knock activity etc

/quote]

any reason for the 60 degree angle?

*The sensor may be tuned by torquing the attachment bolt is the bolt is mechanically in parallel with the piezo crystal. If the bolt is too loose, or too tight, the centre frequency of the sensor can be incorrect, so the sensor might pickup the valve train noise rather than knocking electrical noise.

My oplogies the sensor tail/loom has to be 60 from the back of the engine i.e. replace the new one in the same position, maybe marke it before removal.

googling reveals that you can throw a CEL if the sensor is not at that angle. As for the pure science behind it i am unsure (still googling) but when i was digging deep into knock sensors a while back the best prcatices said 24NM and the 60 degree angle.

Torque setting QUOTE: *The sensor may be tuned by torquing the attachment bolt is the bolt is mechanically in parallel with the piezo crystal. If the bolt is too loose, or too tight, the centre frequency of the sensor can be incorrect, so the sensor might pickup the valve train noise rather than knocking electrical noise.

re: the 60 angle.. google says the knock sensor is in its simplest form a microphone, and peeps believe it to be directional hence the correct factory angle must be used for correct operation.

[Guest]

 Bazza-NZ']

[quote name='SICNIS said:

i have CEL due to knock being cracked i found it lol thanks bro

bazza yeah bro could be keen and whats your labour charge for installing it,

i heard they had to be torqued up so not to keen on doing it myself for fear of having it to tight or to loose haha

/quote]

No charge for labour as long as you get your hands dirty

keen bro keen pm me lol

[WRXONP]

dont worry about the 60 degree angle and the torque

do it up firm...not loose...not tight enough to smash it

have changed my old one... have no detonation problems with it in stock position

more importantly is the sealing surface as this is the earth !!!

[spark_38]

That's probably why the G4 Knockblock utilizes two sensors mounted on different parts on the engine block. It can also tell you which cylinder is knocking too.

[WRXONP]

well you would need 4 sensors for that !! LOL

IMO moving the knock sensor is a band aid for a problem !!

[Bazza-NZ]

 WRXONP said:

well you would need 4 sensors for that !! LOL

IMO moving the knock sensor is a band aid for a problem !!

technology is smart, you only need one not 4 as the ecu will use the crank and cam sync to establish which cycle was fired when the knock occured

and i completely agree. Moving it is not a good idea. If it was meant to be go somewhere else Subaru would have put it there

[spark_38]

I've seen it placed on the intake manifold to aviod error codes...

[Stoffa]

I've got a good one here you can have for $40 if your on a budget, it was on my old engine but I dont need it as I'll be switching to a bosch one to use with G4 knock link

[gazzy2000]

 Bazza-NZ']

[quote name='WRXONP said:

well you would need 4 sensors for that !! LOL

IMO moving the knock sensor is a band aid for a problem !!

/quote]

technology is smart, you only need one not 4 as the ecu will use the crank and cam sync to establish which cycle was fired when the knock occured

and i completely agree. Moving it is not a good idea. If it was meant to be go somewhere else Subaru would have put it there

yup and same goes if subaru states 60 Degree angle and 42 NM of torque... i'd listen

@WRXONP - imagine if you will, your engine experianced det (for what ever reason) wouldnt you want to know that your knock sensor was installed as per factory specs and therefor fully optimised to instantly react to the knock?

During my extensive detonation troubleshooting in my BH TT to ST conversion i relocated my knock sensor to the usual upper housing + a heap of other locations (incl manifold).. still torqued and 60 degree angle.

In every position i used my knock sensor listening device and recorded on my laptop, i found that the knock sensor picked up the det (of which there was heaps) in every position, incl the manifold.. and in every position the ECU would put the ECU in safe mode due to the det, proving that a relocation works fine.

In saying that i retured the KS to the factory location after finding a relocation didnt fix this/my particular problem.

As for the CEL being thrown, i have read that if there is a KNock sensor CEL after fitting a knock sensor, setting the torque and angle has fixed/cleared the CEL.. key word there.. IF

[Bazza-NZ]

You got a photo of the

 gazzy2000']

[quote name='WRXONP said:

well you would need 4 sensors for that !! LOL

IMO moving the knock sensor is a band aid for a problem !!

/quote]

technology is smart, you only need one not 4 as the ecu will use the crank and cam sync to establish which cycle was fired when the knock occured

and i completely agree. Moving it is not a good idea. If it was meant to be go somewhere else Subaru would have put it there

yup and same goes if subaru states 60 Degree angle and 42 NM of torque... i'd listen

@WRXONP - imagine if you will, your engine experianced det (for what ever reason) wouldnt you want to know that your knock sensor was installed as per factory specs and therefor fully optimised to instantly react to the knock?

During my extensive detonation troubleshooting in my BH TT to ST conversion i relocated my knock sensor to the usual upper housing + a heap of other locations (incl manifold).. still torqued and 60 degree angle.

In every position i used my knock sensor listening device and recorded on my laptop, i found that the knock sensor picked up the det (of which there was heaps) in every position, incl the manifold.. and in every position the ECU would put the ECU in safe mode due to the det, proving that a relocation works fine.

In saying that i retured the KS to the factory location after finding a relocation didnt fix this/my particular problem.

As for the CEL being thrown, i have read that if there is a KNock sensor CEL after fitting a knock sensor, setting the torque and angle has fixed/cleared the CEL.. key word there.. IF

42NM !!!! That seems a little bit tight? (re-read your earlier post and see its 24)

You got a photo of how you have installed your knock sensor?

I replace at 60 degree but i have never torque up the bolt, however i don't use the knock sensor with the Link

[spark_38]

24Nm isn't that tight, a nip with a 3/8" drive ratchet will be around that

[gazzy2000]

 Bazza-NZ said:

42NM !!!! That seems a little bit tight? (re-read your earlier post and see its 24)

You got a photo of how you have installed your knock sensor?

I replace at 60 degree but i have never torque up the bolt, however i don't use the knock sensor with the Link

lol yea 24nm

the torque setting is no great mistery.. its in the factory subaru workshop manual

Knock sensor installed as per stock factory form now

[gazzy2000]

here is my thread on the knock sensor listening device etc http://www.clubsub.org.nz/forum/index.php/topic,7978.0.html

[Stoffa]

most torque wrenches aren't very accurate at a low setting like 24nm

[Guest]

cant say ive ever seen 3/8" torque wrench either lol all the ones we have at work are 1/2"

[Guest]

knock sensor = $100

now i just gotta pick my balls up and do it .. i sussed it out i should be able to do it without having to remove TMIC

ian @ subaru gave me trade for rocking in there with my tonys uniform on