constant knock count of 9, no matter what

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Sep 19, 2014, 08:28 AM

#16

honda-guy

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Quote:

Originally Posted by wreckleford

A constant knock count of 9 means the knock sensor is disconnected or defective.

Based on what you have said you tried I would guess there is probably a disconnect somewhere between the knock sensor plug and the ecu plug. Playing with the knock sensitivity tables won't help.

you are absolutely correct. when they swapped out the knock sensor, they assume it was working, although it was a used one. nothing changed with knock count, so that's when they tried everything else. then they went and unplug the knock on a different car and it did the same thing. that's when they figured out i was the knock sensor. Put on a third one and everything was good.

crazy that it doesn't throw a check engine code with a bad sensor, just like any other sensor. that would have saved a lot of hassle, instead of just defaulting knock to 9.

thanks for all the feedback.

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Sep 19, 2014, 10:24 AM

#17

PAdutch

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Quote:

Originally Posted by Hiboost

Update just in case he doesn't get back in here right away. They tried a 3rd sensor and all seems to be normal again... I guess never assume! Also if you want to bypass the factory wiring harness the Knock sensor is calibrated to work with a certain wire length and wire resistance so it's not as easy to just replace the circuit as I would have imagined.

Glad you found it...nice to know about the wires

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Sep 19, 2014, 06:31 PM

#18

hutch959

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Quote:

Originally Posted by Hiboost

this is true!.. its calibrated to voltage.
and V=IR
so if you mess with the wire length, you are messing with the "R", which changes the V...

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Sep 19, 2014, 08:56 PM

#19

galantman03

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Quote:

Originally Posted by hutch959

this is true!.. its calibrated to voltage.
and V=IR
so if you mess with the wire length, you are messing with the "R", which changes the V...

Since I am battling this issue right now, you wouldn't happen to know the factory ohm reading of the resistance? I cut both wires, and ran them through mil-spec plugs, and I would like to check the wiring resistance.

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Sep 20, 2014, 06:16 PM

#20

hutch959

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i do not... but if someone had a wiring harness they could check it right quick and that would be some good info.

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Sep 20, 2014, 06:24 PM

#21

honda-guy

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i think the wires are also shielded to prevent interference, not just regular wires.

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Sep 23, 2014, 07:56 AM

#22

10isace

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Quote:

Originally Posted by galantman03

What resistance are you getting?

I'm no electrician, but I checked my harness with the multimeter set at 200 and I get 2.8 for both wires. I get 2.7 when I touch the probes together (so I don't know if that means there is a .1 resistance on the wires?)

I'm about to do my Mil.Spec connector. Would keeping the wires the same length work or another alternative connector through the firewall for the shielded wires? Looks like there are 3 shielded wires from the ECU (2 go through the firewall), Knock sensor, front o2 and rear o2 (doesn't go through firewall, so no need to cut and most bypass this for WB anyway).

Last edited by 10isace; Sep 23, 2014 at 07:59 AM.

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Sep 23, 2014, 01:12 PM

#23

galantman03

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Quote:

Originally Posted by 10isace

I didn't bother checking, but I fixed my issue and I have 0 counts of knock at any rpm with 200 load right now. Connector was bad, so I was getting no continuity at all, even though the sensor clicked into place. What I did for all the shielded wires was I kept them together until at the connector side, pinned them seperately, and then kept them together after. Yes there are BNC plugs that your supposed to use for shielded cables, but a distance of 10mm is not going to cause any interference issues.

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Oct 10, 2014, 06:42 AM

#24

DanyLeduc

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do you have any pic of your setup? i'm having some real trouble with mine also, giving me a CEL cause of the knock sensor misfunctioning! ( previous owner did a buch of wiring for an alarm system and now that i removed it, it seems that it ****ed it up

)