knock sensor issues CA18DET

[Zenki]

How can I deactivate the OEM Sensor?

I tried every feedback switch, and also tryed to plug the sensor on and fix the sensor not on the bottom.

Knocksensor_fail.jpg

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[Matt]

you need a 500kohm resistor on each knock sensor line (two of them on this ECU) to get rid of the fault code and ignore knock completely

there is no feedback flag for this one that I know of for CA18

[datsunboy]

there is 2 knock sensors on a CA18DET?
whcih pins did they go to? I thought there was only 1 pin going to the ECU for knock

[Zenki]

there is 2 knock sensors on a CA18DET?
whcih pins did they go to? I thought there was only 1 pin going to the ECU for knock

no it has only one,

I have installed an aftermarket one

[Matt]

must have been thinking RB20DET then. i use the same plug on the bench for both ecus

[streetbike]

you need a 500kohm resistor on each knock sensor line (two of them on this ECU) to get rid of the fault code and ignore knock completely

there is no feedback flag for this one that I know of for CA18

Do I need exactly 500kohm resistor or 470 or 540 can do the job ??

[Matt]

Those values (particularly 470Kohm) are fine. Its just a rough number to keep the knock sensor detection in ECU happy

[streetbike]

ok ! because I tried one 330kohm and one 800kohm and I have the dtc code always on ...

[Matt]

Okay try a bit closer to 500kohm. That works on my bench setup

[datsunboy]

can the 500k ohm be confirmed Matt?

I read elsewhere that it was a 1 Mohm resistor needed to bypass the knock sensor?

[bachig24u]

you can join two up in 'series' to get 1Mohm.

connect two ends together and use the other two loose ends to connect to the ecu pins.

[datsunboy]

you can join two up in 'series' to get 1Mohm.

connect two ends together and use the other two loose ends to connect to the ecu pins.

thanks, but that wasn't the question.
the question being, will a 1M ohm resistor work? or is a 500k ohm resistor the answer?

[bachig24u]

you can join two up in 'series' to get 1Mohm.

connect two ends together and use the other two loose ends to connect to the ecu pins.

thanks, but that wasn't the question.
the question being, will a 1M ohm resistor work? or is a 500k ohm resistor the answer?

clearly not, but since you were probably going to go and buy a pack of 10 for a 50c by the time you get confirmation on whether a 500k or a 1M will do the trick I figured you might need another option.

[PL]

The older knock sensors (RB20/25 - looks like a hose fitting) seem to need around 500K and the newer style (SR20 - modern donut style like Bosch knock sensors) need 1M.

Older ECU's supply 7 to 8V and this needs to be pulled down to 3.6 to 3.8V with a 500K resistor to keep the ECU happy. Later ones supply a lower voltage (5V from memory) and this needs to be pulled down to around 3V.

I have a pack of 1M resistors, so for the older ECU's I just put 2 of these in parallel to give 500K. RB ECU's have 2 knock sensor inputs, so now I have a bunch of 4 resistors on my bench test setup!

PL

[datsunboy]

cool, so what is it for the CA18 then....I guess it's 500k ohm, since they look like the RB20 stlye and not the SR20 style?

I have used 1M ohm resistors in the past, and on 2 cars recently.......they seemed to have worked fine so far, but havent really looked into it too much, so wanted to be sure I was using the correct ones.