knock sensor wiring

[alpom]

Where can get my signal from the knock sensor for my knock light? I searched on many site to find the pin # or the color of the wire and i cant find it.
where can i get my courant from the ign ?

I also need the rpm but I think its # 21. green with black stripes wire.
on a 944 turbo 1988

I cant find a sire with all the ecu wiring and color of wires.

[wild man]

Knock output signal is on the 12-pin "knock control diagnosis plug" connector in the rightside footwell. There are a total of 6 wires going to it. They are:

1 (black) +12V (key on)
2 (brown): ground
3 (green/yellow): KLR pin 11 (ground?)
4 (blue) knock output signal
11 (green) Blink code output (active low)
12 (blue/white): KLR pin 1 (labeled "diagnosis", maybe serial output data?)

You will need more than an LED connected to the knock signal though, as the pulse width is only around 1ms long - way too short to see unless looking directly at it in total darkness (after your eyes have adjusted). You will need a pulse stretcher to hold it for AT LEAST 100ms when knocks are detected, in order to see it in daylight.

[alpom]

I have a knocklight/shift light turbo XS... will try this TurboXS Knock Warning & Shift Light: JSC Speed
so i need to use the blue wire not the green

[Rogue_Ant]

The method wild man is describing is best. The KLR is purpose designed to filter engine noise and determine true knock. To not use the KLR knock yes/no output, and supplement it with a simple voltage-level comparitor (the TurboXS one) is silly.

Use what Bosch engineers spent a lot of time on - the system that is tailored for our cars, and works very well.

[alpom]

what do you mean?
I want to use the stock sensor...
I just want to be advertised when there is a knock... so i just connect my knock sensor light to the stock knock sensor....
Porsche is new mecanic for me, every advise is welcome... its my first porsche but not the last.

ps. if turbo xs light is useless what should i use? is there a knock light made for the klr?

[Rogue_Ant]

Check out this thread:

Knocking counting

Then you can get a cheap counter (~$20), and receive the filtered signal from the KLR. The KLR functions as a hardware and software filter to eliminate false knock / sound, and determine true knock. If there is a true knock event, then the KLR will output a (very short) signal for each knock event. Using a counter, we can capture the knock events, and count them.

[alpom]

ok ok... i understand... turbo xs = useless with that.
porsche were better made in 1988 than subaru in 2005.

[Rogue_Ant]

Well its not a "what brand is better". It is a fact of the KLR was designed specifically for the 944 Turbo, while the Turbo XS unit is not.

[alpom]

so the knock counter is thing to buy to be sure there is no anormal knock.
1 ground
1 12v pos
1 for knock event
thats the 3 wire the counter need right?

[Rogue_Ant]

Yep, the ones people have been using with success are the Curtis counters.

[wild man]

I have just checked out the Turbo XS light link, and it IS a pretty cool device, especially with the integrated shift light. It would be most ideally suited for non-turbo P-cars though, and (in my opinion) would be highly advisable to use on the later (high compression) S2 and 968 models (or engines with shaved heads/decks), ESPECIALLY for those doing software tuning.

It would also work nicely as a COMPLEMENTARY device to a knock counter on the turbo cars, where it can be compared with knock counts to determine it's accuracy. But if used as such, I would recommend attaching it to a SEPARATE knock sensor, so as to eliminate the possibility of introducing any noise or loading on the factory one. There IS a place to mount a 2nd sensor, right next to the factory one.

The advantage to this device is seeing the knocks EXACTLY when they happen. But as with a shift light, it would need to be placed as close to the driver's line of sight as possible, such as directly above (or below) the upper part of the dash, lined up with the steering column.

Also, the rpm signal likely needs to be taken directly off of the negative terminal of the ignition coil (or off of the same wire at the DME plug).

[alpom]

hummmm... fine ill sell it or ill wait and buy a 2nd knock bosch sensor.

[nize]

if you have a 951, you already have a bosch knock sensor installed at the porsche factory;
knock counter

[alpom]

ya 1 stock for the knock klr sensor
1 new for the turbo xs light. it make the difference between small medium and hard knock