951Boost

I just received my L/R knock sensor (& injector) harness (very nice BTW) and had a question regarding the “bare/ground” wire that connects to pin#12 in the KLR.

What is its function?

The “black to KLR pin#11” and “clear to KLR pin#13” wires “pin out” to the knock sensor connector plug but the “bare/ground” wire that connects to pin#12 in the KLR just ends inside the harness and doesn’t “pin out” to anything

TIA

theedge

Its the shield wire. Theres a braided shield around those other two wires, but our knock sensors dont have a pin for them due to no "internal" shield inside the sensor itself so no pin on the knock sensor end.

951Boost

Brian, thanks for the response, I guess that it's just another case of German over-engineering then.

theedge

Not overengineered, knock sensors are like microphones so the signal is very weak and low powered. Without shielding it wouldnt work.

951Boost

Yup I understand that. However I've done a few engine swaps using mid 80's/early 90's GM ecu's and while they use knock sensors their wiring is not shielded at all. P car K/S must be quite a bit more sensitive.

kasturbo

How hard was it to replace the harness? Did Lindsey send instructions.

zerMATT951

I just got my LR fuel rail and harness the other day, but didn't pay attention to whether or not the little instruction sheet was for the rail kit or the harness. I think it's for the rail kit though...

I did take a quick look at the harness and noticed several pins/tabs on the ends of the wires. I haven't removed my old harness yet, so I don't know if those wires are home-run all the way to the ECU, or if there's simply another connector in the engine bay that we swap the pins out on. I'm hoping it's in the engine bay, because I really don't want to have to fish all that stuff through the firewall...

kasturbo

Is there a way to test the knock sensor? I replaced the harness, but not sure if the sensor is good or not.

PCinDC

The leads from the replacement knock sensor terminate inside the KLR connector (LR Injector harness is same, terminates inside DME connector).
The terminators on the replacement harness replace everything, the wire and the pin. You'll need to remove the pins from the various pin locations and replace with the new unit. Its quite simple once you get your DME and KLR connector off.

kasturbo

I got the harness replaced, I was asking how to test the knock sensor now.

potent951turbo

On the injector harness the wires do go all the way to the ECU. I put one in my dad's car about six months ago. My only complaint about it is everything is plug and play except that one black wire that goes to the KLR that you have just splice into another wire for. Everything plugs in so cleanly except that one wire.

PCinDC

Yes, but the gentleman above you asked if the wires terminated inside the connector or in the engine bay.

I believe I have seen a procedure in FSM involving a multimeter or oscilloscope. I can look it up for you later on tonight. Clark's Garage doesn't have a procedure.

kasturbo

Oh sorry I didn't see that. I dug up some good tests from the archieves that I'll try tonight. Thanks. Clarks didn't have anything.

eastendr

Mine measure 4.6 Megohms. That'll tell if it's open / short / about right as a first test.

HTH

Rick.