Change your knock sensor!!!!

[AUSVR4]

I've just done what I now believe is one of the most important mods you can do.

I put my DSMLink in and whenever I datalogged it would read huge amounts of knock at wierd times (light throttle, full throttle etc). I couldn't work it out! My CE light (doubling as a knock guage) would go nuts!
No amount of tuning would remove the knock and it was pulling timing all the way back to 0.

But now it's fixed! How? I put my fingers under the intake manifold and felt the knock sensor. At the back of it the plug should be filled with a hard goo substance. It was pretty much gone.
Replacing it with a new one has removed almost all knock (except for high revs/full throttle which is real).

I wonder how long it's been doing this and robbing me of vital power?

They say you should replace the knock sensor at around 80k so if it's never been done at least have a feel of the condition.

/Rant over

 

[jase]

Or do a Jack and don't run a knock sensor, run that fuel from the OG Rd Liberty and cross your fingers? :lol:

 

[AUSVR4]

But what if something fails? eek
It's good insurance

I can't hear pinging so it wouldn't work for me

 

[brisvr4]

New knock sensor will solve a lot of "Phantom knock" problems

 

[Entaran]

Thanks for the heads up, i'll do it while the engines out.

 

[CLuTZ]

So have you re-tuned your engine setup yet??? :shock:

 

[Jonson]

I told you you should have doen that :lol: :lol:
Glad to see it made a difference! and go get another tune and dyno run!

 

[bazeng]

how much was the sensor?

i might get one for the amg

 

[kayarubin]

i paid 100 - 150 bucks i think for mine.... delivered from the US

not that expensive considering how much they look after ur motor!

cheers

 

[BennyGee]

you can get them from Meek (www.meek.com.au), can't remember exactly how much, check his site i'm sure its less than $150.

*** just found product on his site, 1g ones are $172, sorry for the mis-info ***

cheers,
Ben

 

[AUSVR4]

I got mine from JNZ Tuning in the US. Cost a lot less than Meek

 

[Pyro]

sorry to be a n00b here but would some one send me a link or explain in full what knock is, and what a knock sensor achevies?

 

[BennyGee]

Brief description for how I understand it - knock is the name given to when the fuel and air mixture in the cylinder explodes BEFORE the piston has reached TDC (top dead centre) and rather than a controlled burn, it is like an explosion, so rather than nicely pushing the piston back down, it hits it like a hammer whilst it is still trying to move up.

As far as i know this can be caused by excess heat in the cylinders making the mixture explode before the spark goes off, or can be caused by advancing the timing too far (bad tune). I think it is called knock because that is what it sounds like (try going up a fairly steep hill at a slowish speed in 5th gear, you will hear it).

Now the knock sensor is a highly sophisticated peice of equipment (!) lol, that listens out for the 'knocking' sound, and then when it is detected, the ecu automatically retards the timing to try and prevent engine damage.

This is how i understand it, if anyone wants to add anything or correct anything, feel free.

Cheers,
Ben

 

[SIR]

Good to hear you finally managed to remove the old one

Time for a retune and see what power the motor can make

 

[Pyro]

so it basicly prevents detonation?

 

[BennyGee]

the knock sensor? i believe that is what it tries to do, yes.

 

[Pyro]

no worries, cheers for all ya help mate, appreciate it!

 

[rob323]

Just to clarify, a knock sensor does not prevent detonation, it only detects it. It is just a sensor. The ecu monitors the knock sensor and if it the knock sensor put out data that the ecu sees as dangerous, then the ecu is programmed to adjust things like timing to help prevent detonation.

 

[BennyGee]

Just to clarify, a knock sensor does not prevent detonation, it only detects it. It is just a sensor. The ecu monitors the knock sensor and if it the knock sensor put out data that the ecu sees as dangerous, then the ecu is programmed to adjust things like timing to help prevent detonation.

yeah thats what i meant... woops, the sensor tells the ecu whats going on, which in turn tries to prevent it.