1 Knock Sensor, 2 Processors
 

Putting this in the Link forum, but I'd assume it's applicable to any ECU with built in Knock control.

I have the Knock Detective by @FWLRtuning in my car (basically fancy electronic det cans). It uses a 2 wire Bosch donut style knock sensor. I'd like to keep the gauge around, as I still find myself listening to the engine from time to time. The Knock Detective has a signal output which I have wired to the ECU so I can see the signal it's getting, but I can't tell the ECU to do anything with it.

I'm now running a LinkG4x PNP, which has onboard DSP for knock control, however the Link doesn't allow you to assign a generic analog input to the knock control setup.

Options as I see them are
1. Splice the wires from the one existing knock sensor into both the ECU and the Knock Detective. I have no idea if this would work. This seems like the ECU and gauge would end up interfering with each other.
2. Remove the Knock Detective and run the sensor to the ECU only.
3. Figure out a way to run a second knock sensor and have 1 for the ECU and 1 for the gauge. I've seen mentions that FM used to sell a knock sensor mount that used an engine mount hole, so this isn't completely heard of.

Interested in feedback either way and am curious what other people would do in this situation.

I had the FM Bosch sensor on the engine mount. It was a relatively simple hex stock turned on a lathe with appropriate male and female thread on the ends. That seems like the most simple solution.

I would agree if FM was still selling those adapter studs. I suppose I could look into having something custom made, but that's a bit outside of my wheelhouse

My vote would be to allow the Link to do the knock control. Its incredibly capable, and you could set a simple aux out to trigger if knock retard goes above a certain threshold if that's what you're after.

I still need to send my Link in to get a knock pigtail added. That's the only annoying part of the original MX5Link for 90-95.

Dang, that sucks about the NA PNP, thankfully the NB PNP is setup to use the stock harness.

That is likely the path I will go down. My car's setup is stabilizing a bit, so I won't be adjusting my spark map as much going forward. The reason to keep the gauge would be to use the headphone output when tuning, but like I said, that's probably not as applicable as it was when I didn't have any options for knock control in the ECU.

To follow up, what I ended up doing was taking the stock knock sensor harness, clipping the sensor off and adding a connector to the end. I then cut the wire that ran from the knock sensor on the engine to the Knock Detective and added connectors to both ends of those wires. In theory, this should allow me to swap between the ECU and the Knock Detective fairly easily if desired.

I would have rather had the connectors for both the knock sensor and harness and created a proper adapter, but the knock sensor that's attached to the car has a hard wired cable. I would've had to get another sensor, drill it out, remove the old one, add the new one (which is a pretty annoying job), rewire, etc...

These Dupont style connectors aren't appropriate either, but they'll work for now with a bit of extra tape to secure them.

https://cimg1.ibsrv.net/gimg/www.mia...783826aaee.jpg
Stock harness wire clipped
https://cimg0.ibsrv.net/gimg/www.mia...f716b020c5.jpg
Separated the wires out
https://cimg9.ibsrv.net/gimg/www.mia...9edeaf28e8.jpg
Connected to the wires from the Bosch knock sensor that came with the Knock Detective

Appears to be working well enough. I realize this is probably a pretty sensitive area for electrical noise, hence the shielding on the wires, but a quick test drive showed reasonable results. I don't know how much better it might look with better wiring. Does aluminum tape add a layer of shielding? I suppose we'll find out.
https://cimg0.ibsrv.net/gimg/www.mia...b7bc440c8f.png

I will probably make another thread regarding setup for the sensor.