i know you guys dealt with this many times, but im really desperate, spend weeks trying to work it out...

so, error code 34
knock sensor problem...
my ecu shows 0.568ohm
knock sensor shows 0.580ohm
so i would assume i need new knock sensor
but i bought two (so i have 3 all together, mine old one and two new ones)
bought both not from ebay, from proper shops, one for 85£ another for 160£
and both shows freaking 0.560-0580ohm
put 1meg ohm resistor like it say in here
http://www.zhome.com/ZCMnL/PICS/detonationSensor/detonationSensor.html
same code 34
so that is it?


thank you

Z32 TT 1991 ATM

Not to try and be silly, you are clearing the fault each time aren't you? If so, can only be wiring I guess

yup, cleared every time

this is that i thought, so one day i got so desperate

i got to ecu, found knock sensor wire, took all out, cut it and replaced with my own?

so all new wirring...and still same 34 ?

I'm no expert, but I do believe you can also buy the OEM knock-sensor harness. If it were me, I'd replace the existing harness with the OEM item, rather than splicing in my own wiring. Not that it can't be done, but due to sensor location etc., I'd feel happier knowing that I'd replaced everything possible, just so I'd not have to go back and take everything apart again

Just so we are working of the same page. These are the FSM diagnostics for the Knock sensor. Can you confirm

that you have gone through them?

EF-EC 132.pdf

EF-EC 179.pdf

The knock sensor also has a sub harness. Only one signal wire is connected to the sensor (see EF-EC 132) , the second wire is for the

earth shield. It is very important that the earth shield is intact as it goes from the sub harness plug up to the sensor (penultimate

paragraph):

http://twinturbo.net/nissan/300zx/forums/technical/view/1146799/The-important-truth-about-your-knock-sensor.html

 

 

Edited May 21, 20205 yr by AndrewG

question to AndrewG

so, one wire is going from ecu to sensor and wire have to be sheldied and shielded wire is crucial

so what about ground? from where should it be connected to...?

Using shielded wire like this:

The ground can be anywhere near the ECU as below:

How are you dealing with the sub-harness? It is under the lower plenum and almost impossible

to reach with the engine and gearbox in situ. Have you relocated the detonation sensor?

 

How did you install the 1 mega ohm resistor?

The detonation sensor circuit is the left hand plug in the picture below (white and black wires main harness side).

The left bank VTC plug (yellow dots on plug with green/black and black/red wires main harness side). The main harness

plugs are interchangeable and is it not unknown for them to be incorrectly swapped over, this will give a code 34.

Edited May 23, 20205 yr by AndrewG

1.so, i know that is shielded wire, bought one long time ago, just for this car, but i havent used it ?

2.spend many hours looking at ecu, never notice that ground there,will try to find it tomorow ?

3. so if im replacing knock sensor wiring with my owh,  but there's only one wire going from ecu to sensor, how should i conect that ground?

4. while ago i took half engine apart, changed sensor to new one and connected sensor (because i forgot to connect sub harness to sensor then i did full engine rebuild) i change sensor because it didnt show rigth voltage ( now shows 568ohm)

and just incase i bought another sensor, tried to relocate, hoped magic 34 error will disappear,  but nop.......cause like i said i spend hours thinking looking praying and trying all sort of things ?

5. i did instal 1meg ohm resistor

nothing changed

6.i thought that may be problem (connecting wrong wires) i checked and checked and im positive that they are connected corectly, just incase will check again in the morning

7. english isnt my language, so if i made any mistakes sorry for that ?

11 hours ago, Vaidutis Juršelis said:

2.spend many hours looking at ecu, never notice that ground there,will try to find it tomorow ?

Just checked for you, the factory earth point for the detonation shield is (F11) shown above as "Engine Ground". Just

earth one end of coax wire.

Circled below.

Edited May 24, 20205 yr by AndrewG

seen that ground before ?

 

checked connections, they all good, i mean, i connected wright wires. VTC is not conected to DET

 

im at car right now, 

just connected shielded wire, same result,  no luck, still 34

 

If the issue is not the sensor or it’s harness not the ground of the sheathing. The issue must lie with the cable to the ECU. I would test continuity of the white cable from the connector pictured above and the ECU itself. 
Its a very simple circuit. 

For the 1MΩ resistor workaround to work the F8 plug - ECU side (see above) needs the ground to be present.

Edited May 24, 20205 yr by AndrewG

VJ, just to be clear. How are you reading the code 34?

How are you clearing the code 34?

Edited May 24, 20205 yr by AndrewG

15 hours ago, Stephen said:

I would test continuity of the white cable from the connector pictured above and the ECU itself. 

you mean brown wire?

i did test it, shows stable 0.580ohm

 

15 hours ago, AndrewG said:

For the 1MΩ resistor workaround to work the F8 plug - ECU side (see above) needs the ground to be present.

F8? ? you mean this F8?

https://www.impactblue.org/content/display.php?page=caref.efi_harness

 

"ground to be present" could you be more specific, i mean how exactly should i do it

 

 

i read and clear the errror with datascan consult

sometimes i disconect battery for nigth, so error should clear it self

i read error once from flashing ligth on ecu,  but that was weeks ago

7 minutes ago, Vaidutis Juršelis said:

F8? ? you mean this F8?

https://www.impactblue.org/content/display.php?page=caref.efi_harness

just realised which F8 you mean ?

15 hours ago, AndrewG said:

For the 1MΩ resistor workaround to work the F8 plug - ECU side (see above) needs the ground to be present.

i tried to do it, not sure if i did correctly

i think i did everything right as that guy in this page

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

 

 

 

1 hour ago, Vaidutis Juršelis said:

you mean brown wire?

What makes you think that on your car the Detonation sensor signal wire is Brown?

The factory wiring diagrams show White (pin 23 ECCS connector)

This is a coloured ECCS diagram to help you.

ECCS_colored_m.pdf

Edited May 25, 20205 yr by AndrewG

in the diagram yes its white, but in reality its brown

AndrewG if i cant fix this problem till end of week

do you mind coming to my house and helping me out? ( I'm willing to pay you...(plus i have few beers ? )

i lice in london IG10

are you sure you have the det sensor wire? there is a 02 sensor plug I believe in the same area, it's not uncommon for the 2 to be mixed up if they get unplugged for work. 

 

quite possitive

because i cut the sensor wire (next to plug, photo above)

got to ecu, found 23 wire,  cut it, and replaced all of it

so now i have wire going from ecu, going outside through passenger door, over fender, and connected to knock sensor wire.....

 

im serious guys, i will pay anyone who can come to my garage and solve this problem

Are you looking to fix it with a new knock sensor or sub harness or are you just wanting to use the resistor again?


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well sensor is new, i changed it, it shows correct voltage.....

tried using resistor, didnt work out...

 

i just want my car running normal, do not care how ?

 

Maybe talk to a local auto electrical chap. It’s a very simple circuit. And to be totally honest it’s use is pretty limited. Just get it by passed.