Knock sensor relocation

[Talamascan]

Anyone here have experience with relocating their knock sensor? My OEM sensor may be acting up and I have no intention of ripping off half the engine to get to it. Relocation kits for our engine are available and I'm just wondering if anyone has used one and what the results were.

[fourdrinie]

worked for me...eliminated code...

[Talamascan]

Good to hear. $130 sure beats $1,000 to basically ransack half the engine.

What symtoms accompanied your code?

[fourdrinie]

there were no symptoms that I could detect...just the CEL

the trickiest part was finding the correct length bolt, I went for a 100mm size which I had to get from a supply house listed in the yellow pages as no retailer had one.

[fourdrinie]

http://s232.photobucket.com/albums/ee245/gotspeed0921/

where-is-j30-knock-sensor-cable-ecu-sid ... 82494.html

[Talamascan]

Thanks. The pictures are invaluable.

[Talamascan]

Got this from the z1 site:

"A diagnostic trouble code 34 generated by the ECU means that the circuit for the detonation sensor is broken, not that the ECU has "heard" detonation. The ECU is always looking for a resistance in the detonation sensor circuit of around 1 mega-ohm. If this resistance is not present the ECU throws a code 34 and also goes into a self protection mode in which ECU switches to more conservative safety maps with less timing and more fuel as well as lowers the boost level on Twin Turbo models by opening solenoids that normally bleed off some of the pressure to the wastegate actuators. The faulty part in the detonation sensor circuit is usually the sub-harness between the sensor itself and the EFI harness."

In my case, I'm getting quite audible detonation, but the ecu has NOT switched to a richer map, meaning that if the knock sensor is the culprit, it's not the harness (because the 1 mega-ohm resistance is apparently still present). Anybody encounter a situation where the problem was the actual "microphone" itself? My guess is, if the microphone goes deaf, then the ecu simply has no idea what's happening and does nothing to attempt to prevent the detonation. If that's the case, it seems that all I need to do to temporarily alleviate the detonation until I can install a relocated sensor is disconnect the harness. Any thoughts?

[suicide commando]

Anybody know if a 300zx knock harness will fit the j and the j sensor?

[jdurrty]

egr-issue-t569937.html

[Talamascan]

Update:

Disconnected the knock sensor circuit over the weekend and lost 30 hp, idle went to 2k and the car generally ran like crap, so now I know what the safety mode feels like (and, of course I got an ecu code, but no CEL). Unfortunately, the engine still pinged even in this mode, only the pinging changed from mostly during mid -throttle inputs at speed to mosty pinging right off the line. In order to get the car to stop running the safety mode, I had to disconnect the battery.

Sooo, I definately know that I do not have a faulty knock sensor circuit signal, but what I have yet to figure out is if I have a faulty knock sensor microphone

[yodawill2000]

Have you ohm'd it out at the harness yet ?

[Talamascan]

I dropped it off at a very experienced mechanic this morning with a full update of what's been going on. At first he thought it was most likely the KS, until I told him that I didn't get a KS code until I actually disconnected the harness. Since the code only trips when the ohm circuit is interrupted, not when the microphone actually hears detonation, I'm super curious to figure out what happens when the circuit is fine but the microphone stops "listening." No one, even on the 300zx forum has offered their input as to this question. I don't know enough, that's for sure. Maybe the circuit is interrupted each time the mike senses detonation, or maybe the circuit is only interrupted when the harnass (which is the weak link on our cars) is damaged, or (more likely) maybe I'm confusing the act of triggering the ECU trouble code with the act of actually modifying timing on the fly.

Anyway, since the car still pings either way, he also indicated it might be an EGR problem, but I've gotten no CEL of any kind. Most frustrating.