half past twelve

I can not find my knock sensor, does anyone have a picture of the location? I have no idea what it looks like so I can not find it.

BigIslandSevens

iTrader: (4)

It is above the front rotor's spark plugs. It is a HEX shaped sensor with 2 wires coming out of it. Kinda hard to see with the power steering pump in the car. I'll try to find a pic if you give me an email. Aloha, Dave

half past twelve

Also, how hard is it to remove so I can relocate it?

DCrosby

Why ?? What Huh ??? Relocate to where ?? The Radio ??? I've heard about retarded base, but that's going a bit far

alberto_mg

Relocating? Ain't gonna happen dude.

As for where is it, remove the intake elbow and look right above the leading top spark plug. You'll see a big 1" diameter, bronze hexagonal bolt looking thing with a wire sticking out of it. That is the knock sensor!

93BlackFD

is there one or two stock, i have two on my car....i figure more is better

half past twelve

I need to relocate it so I wont hit fuelcut with my damned god-forsaken PMS. I still hit fuelcut with it, and the only fix is to relocate it.

half past twelve

https://www.rx7club.com/showthread.p...tting+fuel+cut

Wargasm

Driver's side of engine, above spark plug.

B

Drifter93

Half past twelve are you the kid that has the red rx7 in Del Rio? If so don’t take to much advice from the two guys that drive FC down there. You are better off asking on this forum or the other forum about your FD. TRUST ME…

XSTransAm

I didnt know we had a stock knock sensor, what does it do? any feedback to the ecu?

CapitanCombo

Surely it feedbacks to the ecu
but i don't think the ecu will retard the ignition
maybe it will just cut fuel as well as when you hit boost over the predetermined values

BTW most of cat equipped/fuel injected cars have it

BinaryRotary

Sounds like somebody has PMS. You cannot relocate the knock sensor( that is, unless you have a degree in mechanical/electrical engineering and plan to re-design it, which will also probably mean you will need to drill and tap the block). You need a knock sensor on your FD. One knock or ping can destroy an apex seal yesterday. I suggest you find another place for your PMS.

CapitanCombo

half past twelve, if you unplug it you will disable one of the device the ecu has to prevent you from blowing the engine
just relocating i think will not change so much, if you still relocate it on the engine
the knock sensor is usually a small accelerator, sensing the acceleration given to the block by the a/f mix exploding (detonation)
if you just change the position on the engine it will still sense the knocking (even if there are some positions more "sensitive" for it)
but maybe you only need a less sensitive sensor, in this way you can try to relocate it, even if i think that Mazda engineers did not put this randomly

Drifter93

The knock sensor on our cars due send feedback to the computer. In my case a while back the wiring for my knock sensor went bad and every once in a while it would tell my computer that I was getting knock when I wasn’t and so the ECU would tern my boost down to 6psi. But that problem is all fixed now.

XSTransAm

what about with the haltech, does that utalize the knock sensor?

BinaryRotary

Experiment all you want, it's your motor, but I would strongly advise against moving the knock sensor. If there is one fragile aspect of a rotary engine it is its vulnerability to detonation. You want that knock sensor doing what it's supposed to do.

XSTransAm

why so much emphasis on the knock sensor, Arent our engines toast if they get a single knock count?

I dont think the ecu responds to the knock quick enough to save the engine anyways. Also knock sensors work on frequencys, when you change out your exhaust you change the factory specified frequency and are probably sending the sensor false readings.

Im not positive on this information, im just carrying over what i know about modern day ecus and how they interpret knock and their reactions

DCrosby

Yeah sorry, that was my intent with my sarcastic remark...
There have been people with the J&S Knock sensor, that had wild engine problems when tuning, and then turned off Knock / Spark Retard, and BOOM engine blew as soon as they did another run... basically a knock sensor is nothing more than a microphone that "Listens" for abnormal background noise in the rotor, that would indicate pre-detonation, that why it's near the spark plugs, that's where this would happen, I'm actually adding another KS to the other rotor housing, then my AEM will let me retard the timing on either sparc individually depending on which one is starting to detonate....

Anyhow, get someone to look at your fuel maps, and see why it's retarding your sparc... (and BTW Knock sensors don't cut fuel, you'd lean out and blow your motor... you always cut sparc...) that will fix your problem, don't go after the safety device, go after the problem...

half past twelve

Pm sent.

Mahjik

iTrader: (1)

Guys, it's a fairly common problem for EFI/PMS users to relocate the Knock Sensor.

half past twelve, try using the rear rotor and see if that fixes it.

half past twelve

BinaryRotary

No system is perfect, but if the ecu detects any type of "vibration" behavior similar to a knock or ping it retards the spark immediately to prevent another knock or ping from occurring. The apex seals can probably endure several knocks or pings over the life of the engine--knocks or pings you and I will never detect. But if you get any bad fuel or some other timing anomaly that leads to repeated knocks/pings the apex seals are not going to last long.

DCrosby

Well you are partially right, Knock sensor depends on a base level of sound, and pre detonation on hot carbon deposits happens over several combustion cycles, which is not audiable to the human ear, but has an spike on a waveform, this then tells the ecu that an abnomal combustion event has happened, and it will retard spark and listen again... then it will start going back to it's normal program, the factory program knows what to listen for, but when you tune a J&S or AEM or whatever. you have to set a threshold of what's normal turbo / combustion sound and what's not.. Typically you set it and see if it retards prematurely, then you up the value untill you tell that the AFR is causing pre detonation on a mild level, and set the value there, add fuel and go on with your life...

Mahjik

iTrader: (1)

There should be unused sensor mount on the rear rotor (just like the one which is being used on the front rotor). Just move the sensor there and see if that fixes the problem.