iluvrx7z

Quick question. Just aquired a new S-AFC II Limited Edition, it claims it has some knock sensor function.

I was wondering if it were possible, or worth it to connect it to the knock sensor on my 87TII.

If so which color wire it would be, or which pin. Thanks in advance!

Dan

Scott 89t2

you can get the wiring diagrams from www.fc3s.org ...

iluvrx7z

Would it be worth it to do? I mean how accurate is our stocker?

On the fc3s.org...You mean the FSM? Cuz I really suck at reading wiring diagrams lol

Thanks for the help!!!

Dan

NZConvertible

You should get the wiring diagrams and learn how to use them. They will make working on your car's electrics much easier. If you suck at reading wiring diagrams you shouldn't be mucking around with ECU wiring anyway.

The S4's knock sensor goes to a knock control box near the ECU which interprets the sensor's output and sends a signal to the ECU if knock reaches a certain point. The ECU retards ignition timing when it receives the signal from the control box.

The wire from the knock sensor to the knock control box is grey, but the section in the engine bay is shielded so stay away from it. Locate the control box and tap into the sensor wire there. The wiring diagrams show where the control box is.

iluvrx7z

Thanks for the help! I'll go take a look the diagrams and tap into it!

Dan

iluvrx7z

Well I have deduced from the FSM that the control box is inside the car near the ECU however the picture wasn't very descriptive, I'll take a better look tomorrow.

However I was just wondering if anyone knew if its even worth it to bother ie. is the sensor any good, and will the S-AFC recognize the data its sending.

I've tried searching but I didn't find any usefull information.

Thanks in advance.

Dan

iluvrx7z

bump

Scott 89t2

it's probably not that good... considing the stock ECU ignors it past 3-4000rpm anyways.

ERAUMAZDA

Hmmmmm. Once you get one knock the engine is pretty much gone. I heard that the knock sensor is pretty much useless. With all the engine frequency...you would have to get a very expensive knock sensor.

NZConvertible

What Scott said is right, it can't "hear" much past 4,000rpm because of all the other noise. It's really only useful for preventing detonation caused by low-rpm, high-load situations, i.e. lugging the engine.

iluvrx7z

Ok, thats pretty much all the info I needed. Thanks for the advice guys!!

Dan