Jeff N.

Trying to wire in a knock counter; can someone help with a couple of Qs?

- Under the dash on the passenger side, there are two plugs. One seems to have a factory wire harness, the other has no harness attached. We want to connect to the second, non-utilized plug, correct?

- On that second plug, I should see 12v+ with the ignition on at Pin1. Right now, I don't seem to get the expected voltage at Pin 1 or any pin on the second plug.

What am I missing?

Thanks!

JohnKoaWood

I am a fan of using the stereo switched wires for power, and attaching the trigger directly to the KLR pin 15 wire... but thats just me!

Jeff N.

Hmm. May need to do that as I figured this was an easy one....

How would I ID the KLR wire? Is it a certain color pairing?

Van

Unplug it from the KLR, undo the screw on the plug and cut the zip-tie, slide the cover back and look at which wire goes to spot 13.

I suppose the wiring diagram will also tell you the color.

JohnKoaWood

Post 87 Turbos.. Pin 15 is a 1mm Blue wire on the KLR harness, runs from the KLR to the Diagnostic plug in the engine compartment, the KLR on sensing knock sends a pulse to the diag port via this wire....

86, confirm if there is even a Blue wire If you dont have a blue wire, let me know, and I can send you a pin for the end of the counters trigger that will plug into pin 15 on the KLR... PET lists the same part number for all non S turbo cars... so pin 15 should still output a pulse even though the 86 doesn't have the diagnostic plug (or at least it isn't shown on the wiring diagram like on later cars) and I dont have an 86 here to check..

Pin 13 will almost surely give all kinds of false readings, as this is one side of the knock sensor, which is little more than a microphone, it is constantly energized, broadcasting noise...

Jeff N.

Mine's an 86.

What are we saying here? That the connections (both harness and diag port under the dash) on an 86 might be different?

My car has some sort of diagnostic port under the hood as well as some sort of connection under the dash.

Jeff N.

Hmm. OK, just read a BUNCH more threads that I didn't read the first time. Sounds like the wiring is all over the place. I'll see what's in the KLR bundle and try to ID the pin 15 wire.

JohnKoaWood

ID the pin 15 wire, if you dont have a pin 15 wire, let me know.. I can check an 86 in a couple days.

If there is no wire on pin 15, I can supply a pin to allow you to connect to pin 15...

Tom M'Guinn

There is a bracket that slides onto the very back of the glove box to hold it in place. On that bracket there is an electrical connector (black rectangular connector with easy to access pins that are not connected to anything). I don't have the pin outs with me, but that connector has switched power and the knock signal and makes for a convenient place to wire in a counter, with no need to dig into the harness wires... easy peasey...