Here's the run down.
I have a 1989 Vert with a 1988 block.
I installed an SAFC-II about a year ago and while installing it discovered the Knock Sensor wire was there even though an NA should not have that wire. I connected it to the SAFC to see what it would do and to my surprise gave me an occasional reading of no more then 5.

Jump start to today, and I have a near constant knock well above 30 and usually in the 50s. This has been going on since about November. For the longest time I thought this was caused by the engine running lean. I did several things to try to clean up the fuel system, rebuilt injectors, new fuel line; nothing helped. So today I plug a volt meter into the O2 sensor (after the car is warmed up) and discover that the car is in fact running between stoich-rich and only going lean on decel.

So this leads me to my questions.

1) Where is the damn knock sensor? I thought I knew but can't find it. I'm guessing it would be in the same place as on a S5 T2, but I don't know exactly where.
2) Can you test a knock sensor to make sure it's working within spec?

Any information would be greatfull, I'm thinking of unplugging it entirely from the ECU and see if that changes anything.

 

Front rotor housing above the spark plugs IIRC. Its a big "nut" looking thing with one wire. The FSM should have a spec.

 

Above the spark plugs? Hmm...that'd be hard to miss. I'll have to check again in the morning, but I don't think its there. I wonder what i have my SAFC plugged into then...

BTW, what part of the FSM would it be in you think?

 

Probably S5 TII's Emmissions section. I'll look for it here in a bit....

 

That's alright I'll look just needed to know the section.
Thanks!

Edit: It was on that section and now I'm thinking that I either don't have one, or it's dangling somewhere...

 

That is a pic of my TII's knock sensor.

 

Son of a bitch!
I don't have one! I couldn't possibly!
I have a S4 block on my car and that hole isn't on those housings!
I wonder what i have my SAFC plugged into then....lol

 

check your N/a's ECU pinout

 

That's what i'm trying to find.

 

yeah i hate looking for the pinout its a bitch to find in the FSM they might have it in the "grounding" thread in the archives

 

Well i'm also downloading the SAFC wiring diagram to see what it says and i'll compare it to the FSM diagram.

 

From what I have read the knock counter on the safc is pretty much useless.

 

Well it seems i have it jacked into the Solenoid Valve for the Variable Dynamic Effect Intake Control.
Which I think is the 6PI system. Can anyone confirm this?
Bah it is...i think i might now the problem with my car now. LoL

 

lol if it hooks up to the VDI then it should go nuts arount 5500rpm. Next time you drive check it out at that rpm.

 

Actually it usually goes to 0. Tomorrow I'm going to disconnect the SAFC from it and connect a volt meter to that line and see what it reads.

 

This is a lesson on why you should read the wiring diagrams for your car before commencing electronic work. Nearly all the info the manuals that come with Japnese electronics are written specifically for domestic models. We all know the Japanese market did not get NA engined FC's, and we know the NA engines do not have knock sensor. Logic says that pin is for something else, in this case the VDI solenoid (not 6PI).

Because you've tapped into a switched ground wire, if you measure the voltage at that wire while driving you'll see ~14V when the VDI solenoid is off and ~2V when the solenoid is on (above 5200rpm).

 

Actually it's 12V for off and 4V for on. I read the FSM and have learned my lesson.

 

FSM says "below 2.0V". Page F2-80, pin 2M.