RB26DETT Knock Sensor

[Genesis®]

hi guys,

got 231awkw @ 1.1 bar with PowerFC on the dyno yesterday. Happy with the results but not happy that the laptop (datalogit) and ITC shows KNOCK value = 1. Tuner said that the knock sensor might be disconnected and the reading will be a constant "1" regardless whether the engine's pinging or not. He had to use a oscillascope (sp) to listen in for any pinging/knocking during the tuning and 231kw was supposely a safe tune for me

i have been reading through the rb26 user manual and tried locating the knock sensor but to no avail. Any of you guys know where the sensor is located?

thanks in advance.

[Boosting]

Sorry i know its off topic but who tuned your car and what mods do u have.

[TODA AU]

i have been reading through the rb26 user manual and tried locating the knock sensor but to no avail.  Any of you guys know where the sensor is located?

thanks in advance.

There are actually 2 knock sensors on the RB26.

Both are located on the inlet side, under the intake manifold. (approx 3/4 way up the block)

1 is in line with Cyl 2, the other is in line with cyl 5.

They're round & black in colour with a 10mm bolt throgh the centre.

Plug is also black, 2 wire. Projects from the circular sensor @ approx 45deg.

Hope that helps.

[Genesis®]

There are actually 2 knock sensors on the RB26.

Both are located on the inlet side, under the intake manifold. (approx 3/4 way up the block)

1 is in line with Cyl 2, the other is in line with cyl 5.

They're round & black in colour with a 10mm bolt throgh the centre.

Plug is also black, 2 wire. Projects from the circular sensor @ approx 45deg.

Hope that helps.

thanks Adrian. i did try running my hands down the manifold to try feel for it but nothing. I guess i will jack the car up to have a better look from undernealth. It's irritates me to look at the ITC and have the knock value at "1".

Sorry i know its off topic but who tuned your car and what mods do u have.

car is being mod for the occasional trackwork. For the engine department, i have got ARC intercooler with pipings, Trust oil cooler, Trust sump, JUN adj exh/int cam gears, new belts, oil/water pump catch can, crank, twin air pods, avcr and power fc. Induction side, i have R34 GTR turbos pushing a safe 1.1 bar with full turbo-back exhaust system.

Chapmans & Chapmans at Wollongabba did all the engine work/mods for me and Mercury Motorsports did the tuning because they have the datalogit software and also one of SAU_QLD sponsors. Would have preferred Chapmans to do the tune because i have seen some very positive examples of Andrew's work.

[TODA AU]

thanks Adrian.  i did try running my hands down the manifold to try feel for it but nothing.  I guess i will jack the car up to have a better look from undernealth. It's irritates me to look at the ITC and have the knock value at "1".

Glenn,

Look on the block, just forward of the water~oil heat exchanger where the oil filter mounts, above the front diff... Almost directly above the engine mount bracket, high on the block, hard up against it you should see the sensor (the forward one)

If it's not present, you'll see a raise circular boss where it should be. (With a central thread for the retaining/attaching bolt.

You will probably need a mirror & a torch...

Cheers

Adrian

[Genesis®]

Adrian.

[Duncan]

I had a knock sensor problem as well, seemed a former owner had not liked the reading it gave. So right at the computer they wired the ECU knock sensor input to a constant 0v...so it always read 0.

Anyway, check that first, find the ECU pinouts, follow that wire and make sure it hasnt been fiddled with

[Genesis®]

thanks Duncan.

why would anyone want to remove/disable the knock sensor though? :confused: I for one would definately like to know if my engines pinging

[Duncan]

I couldn't agree more, I hooked it all back up.

My theory is there may have been an "overactive" knock sensor that was sending the ECU into safe mode...and it was easier to cut a wire than to replace the sensors.

After all the knock sensor is just a little microphone

[Genesis®]

i went thru the whole pdf file and finally found a page on the detonation sensor wiring. No diagrams to show the location though.

Duncan - how was your sensor disable?

[Genesis®]

many thanks to Adrian and Duncan.

Spent some time tracing and testing the wires and found out that the connector was dirty. Gave it a good cleaning and woops, my knock sensor is back online

went out for a drive and highest knock value registered was '32'. Did some research in here and it seems that anything less than 40 is fine. Will probably give it a good hard drive soon to see if the value goes up any higher.

[GTR-Ben]

Correct me if i'm wrong, but i believe the knock sensors do nothing but give a number when connected to a PowerFC.. as unlike the stock ECU the PowerFC does not remove timing etc if it sees knock..

It says this in the manual, also I think says anything under 60 is normally safe.

[mabru]

Right PowerFC's won't pull timing like the stock ECU. So all the sensors are good for with the PowerFC is the numerical reading which is what it sounds like he wants.

[fsmout]

Yeah i am having the same problem. Had the car on the dyno and my tuner said that the knock sensor isnt giving a reading (i also have a PFC and want the numerical reading for further tuning).

I will try and give it a clean out, i thought i needed new ones!

I priced new items from nissan and they quoted $300 each!! I found a wrecker with a half cut who will sell them for $95 each which isnt to bad.

Does anyone know if these sensors usually fail??

[rickhead]

I've had mine replaced as well. The guy who did it for me reckoned that 1 of them was an absolute bastard to get to. Took him ages to replace. If you can get them for $95, grab them, I was charged much more...

[fsmout]

yeah i was told they have to take the start-motor off to get at the rear one? Yeah they said it would be 2 hrs labour + the $95 each so about $330ish?

I just hope they work!!

I am definitely going to give them a clean out to see if they are working though