I've been reading alot about relocating the dett. sensor, as i have done mine, but still keep getting 34. Anyways, almost every write up seems to have a sentence similar to this, eg. 'contrary to popular belief, and the nissan manual, the dett. sensor only uses one wire, the other is said to be a ground, but it is not'.

 

Right, if that is the case, then how is it possible to bypass it using a 1 meg resistor, as it would only be connected to one side of it, and the other going to nothingness (?)

 

Just wondering if anyone can clear this up for me, and to tell me (pic would be lovely) which pins from the ECU (not the sub-harness) go to which pins on the dett. sensor, reason being, I have made my own sub-harness, and just want to check I have got everything correct, cos I can't shift that god damn code 34, and I miss my tubs :-(

 

Cheers ya'll....

Hi

You need to connect both ends of the 1meg resistor, there is a positive and a ground. Undo the plug and connect the resistor within the socket that goes to the ecu.

Ive just done mine recently. Look in the faq section for info.

 

Cheers

Graham

Cheers mate, I knew that, it's just the write ups seem to contradict themselves, nevermind, just being over critical matey :-)

>> the other is said to be a ground, but it is not

 

the pin is a real ground but it is used to shield the signal wire.

The sensor is grounded by the metal plate on the bottom of the sensor. (which makes contact once the sensor is bolted to the engine).

The signal pin of the sensor connects to pin 23 of the ECU.

 

if the 1 mega-ohm resistor trick doesn't work, it caused by a bad wiring harness in most cases, so it's easiest to solder the resistor directly into the ECU:

remove the bottom plate of the ECU and solder the resistor between pin 50 and pin 23 (make sure it doesn't make a short anywhere else)

The resistor isn't curing it, so, I'm gonna run a screened cable spliced from the ECU to the dett. sensor, I presume that would be the same, 50 and 23? 50 being the groundy bit?

Sorry for mythering, just trying plan out what I'm gonna do tomorrow :-)

 

So using a screened cable, I would splice the centre to pin 23, and the screen to pin 50, sound right? I connect the centre to the signal pin of the sensor, but what do I do with the screen? Connect it to the other pin? Thanks for your help buddy....

 

I would consider bunging a resistor straight on to the ECU board, but how dangerous is this? (i.e. what if I get dett and don't realise)

 

That's a last resort tho really, as I have relocated a new dett. sensor, so would rather use that TBH...

 

Thanks for the help buddy....

Edited January 12, 200917 yr by Tudor...
I cocked it up the first time

The wiring is very tight at the ecu end, make sure you are connecting the resistor to the right plug ie going to the ecu and not the dett sensor. There is a dett sensor faq in the faq section which will help.

You can put wire tails on to each end of the resistor to make fitting easier at the ecu end.

I know this may sound a daft question, but you definitley have a 1 megaohm resistor?

Try this link

 

http://zhome.com/ZCMnL/PICS/detonationSensor/detonationSensor.html

Edited January 12, 200917 yr by groover
added link

Yeah I have mate, I used to be a electro-medical engineer, so got that covered :-) I even tried a variable resistor that I use for test purposes, you can set it to anything up to 1 meg, checked that and it was exactly 1 meg, but still same probs.... Cheers.

I'm gonna check the continuity from the engine bay plug to pin 23 tomorrow, if there is no continuity then I know there is a problem with the loom, however, and I know I am being pessimistic, but I'll be pretty stumped if the loom is ok! Fingers crossed...

Hi

if its not the resistor then you can be pretty certain that there is a break in the loom, also continuity test the ground, to be sure

 

good luck with it and post up the results

 

Cheers

Graham

>> So using a screened cable, I would splice the centre to pin 23, and the screen to pin 50, sound right?

 

no, you only have to run a wire from pin 23 to the signal pin of the sensor.

the sensor is already grounded and connected to pin 50 once you bolt it to the engine.

 

>> I would consider bunging a resistor straight on to the ECU board, but how dangerous is this?

 

the resistor trick bypasses the dett. sensor, no matter where you place the resistor.

Bypassing the sensor means the ECU isn't able to react to detonation picked up by the sensor and *could* result in engine damage.

 

 

> but I'll be pretty stumped if the loom is ok!

 

if the loom is ok, then you have a fried ECU...or the part inside the ECU that handles the dett. sensor signal.

Have seen this once, but is very rare though.

When I re-fitted my engine, a while ago, I did rather stupidly (all be it a simple mustake to make) get the plugs for the dett. sensor and the cam VVT solenoid the wrong way round, maybe that could've done some damage, eek, gonna go and do a continuity test in a minute, once again, fingers crossed!

 

Thanks for the info guys, I'll let ya know how I get on...

i too just rebuilt my engine! & the old sensor was defunked! so decided to just carry on & do a bypass but since reading up on how important this dett/knock sensor is i have ordered a new one & fitting it in its correct place. when we rebuilt engine we also done a egr valve & plenum bypass so this makes it much easier & quicker to take the plenum & inlet manifold off to get to it.!!.. if i was you, i would do this too:nono:

It's ok mate, I've relocated it to the top of the plenum, not ideal, but far better that bypassing it, I'd rather have phantom knocking than nothing at all!!!

 

I've fixed it now, see the thread I just put up....

 

Hope ya get it sorted mate, and a damn sight quicker than me!!!

If ya don't wanna take off ya plenum matey, re-locate it, there's plenty of how to threads for it 'knocking' around on here! (pun intended) :-)