Idea on how to read knock...?

u6t9 · 06-25-2005, 04:43 PM

Hey,

If someone were to wire up an A/F gauge to the knock sensor on our cars, is there any way that we could get it to "read" knock? I'm sure you would need to modify the voltage comming from the sensor, but is the concept good? little knock>red lights, Medium knock> yellow, lots of knock green.

let me know what you guys think.

Burnett03 · 06-25-2005, 06:55 PM

Quote:

Originally Posted by u6t9

Hey,

If someone were to wire up an A/F gauge to the knock sensor on our cars, is there any way that we could get it to "read" knock? I'm sure you would need to modify the voltage comming from the sensor, but is the concept good? little knock>red lights, Medium knock> yellow, lots of knock green.

let me know what you guys think.

no.

u6t9 · 06-25-2005, 08:48 PM

hmm.... why not?

94Jettameowpsst · 06-25-2005, 09:14 PM

The fact that if you could make it work would be i guess neat. But a/f gauges dont work for a narrow band o2 sensor for what reason.....they're not accurate enough. Low, medium, and high arent really readings i wanna see when im dealing with knock. Why not just go buy a knock box or a logger, they do the same thing....but with accuracy

steve · 06-25-2005, 10:48 PM

The real answer is that the knock sensor is a microphone and passes the raw sounds to the ECU where it's processed. The ECU takes into consideration if the sounds it's hearing are happening during the time that knock might happen and ignores noises outside of that window.

The Knock display on a new SAFC shows how useless it is to look at just the raw knock sendor output.

Steve

Burnett03 · 06-26-2005, 12:46 AM

Quote:

Originally Posted by u6t9

hmm.... why not?

because i said...

you expect to read knock from a 2g with an a/f gauge when 2g dataloggers cant even read knock?

u6t9 · 06-26-2005, 09:04 AM

i expect to read knock with my dsmlink. I was just sitting at work at it dawned on me that to you just need somthing to read the voltage comming from the knock sensor and i thought if you could rig something (like an A/F gauge) it would be kinda neat. not to mention it would work better reading knock than your a/f ratio. it was just a stupid idea i thought i would throw out there.

spyderturbo007 · 06-27-2005, 10:51 AM

Quote:

Originally Posted by u6t9

you just need somthing to read the voltage comming from the knock sensor

Not true.

The ECU learns what is considered "acceptable knock" over a period of time. It then disregards this information as background noise and establishes a baseline from there. This is constantly changing as the car ages, mods change, sensors degrade, etc, etc.

Intercepting the signal before the ECU is worthless and will provide you with unusable information. DSMLink is the only way to do it, as the 2g ECU doesn't provide this information to the OBD-II port.