knock sensor wiring - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

js959 · 12-05-2009, 12:37 AM

hey everyone. my car was running bad for a while then i replaced my knock sensor and it ran like complete crap. so i found the black wire on the chassis side harness before the sub harness going the KS was broke so i soldered that back together. it acually ran a tad bit better.
NOW, here is what confuses me a little, i wrapped some of the wiring before the connector that connects to the sub-harness connector in electrical tape, and it ran a little better. so i wrapped it in even more electrical tape and it ran a little more better. does anyone know what that exactly means? thanks.

js959 · 12-05-2009, 12:57 AM

also, i tested the signal wire continuity, and it was fine. and it has no continuity to ground.
the black wire has good continuuity to ground.

i have an idea or two, but i want to see what yall think.

shinobis13hb · 12-06-2009, 05:21 PM

more tape =))) lol
its a ground wire?? correct?

js959 · 12-06-2009, 08:23 PM

haha, the wires have a good amount of tape around em now.
the FSM says black wire is ground, but i've read other threads about it saying it's a shielding wire, it's kinda confusing to me. the white wire is the signal wire.

i really want to rewire it but i'm not sure if i'd have to insulate the signal wire alot, like it is already. and if it's possible to take the pin out of the ecu connector or just cut and splice near the ecu connector.

Homer_Simpson · 12-06-2009, 09:10 PM

The wire for the knock sensor is a shielded wire, it has a foil-like layer around it to insulate against electrical noises. Get some shielded wires and replace the old hacked up wire.

j20accord00 · 12-06-2009, 09:36 PM

Quote:

Originally Posted by Homer_Simpson

The wire for the knock sensor is a shielded wire, it has a foil-like layer around it to insulate against electrical noises. Get some shielded wires and replace the old hacked up wire.

agreed. I had this problem and it drove me crazy

Rabboni · 12-07-2009, 07:25 PM

Just looked up the knock sensor in the fsm. It only has one wire coming from the PCM and that goes to the knock sensor, then grounds through the knock sensor body. The other wire is a shielding wire to prevent Electro-Magnetic Interference. Spec for testing is Terminal A of the knock sensor connector should have 500 to 620 Kilo-ohms resistance to ground. The shielding wire should have almost no resistance to ground.

js959 · 12-07-2009, 09:16 PM

i really want to rewire it, but i can't find any shielded wire. does anyone know where i can get some? or a site to order from?

js959 · 12-08-2009, 10:31 PM

is this a straight up rewire? or is there anything special that i should know about?

redline racer510 · 12-09-2009, 08:23 PM

man i think finding sheilded wire is going to be a bit tricky, try searching online, or try asking the dealership if they can get you some bulk sheilded wire.

Homer_Simpson · 12-09-2009, 09:59 PM

Quote:

Originally Posted by redline racer510

man i think finding sheilded wire is going to be a bit tricky, try searching online, or try asking the dealership if they can get you some bulk sheilded wire.

Not tricky at all, I bought this a while ago.
Belden 6300FE 18/2 Shielded Plenum

nrmskate · 12-09-2009, 10:03 PM

I havn't read through all the post's, but, in order to just bypass the knock sensor and avoid getting an CEL, is running a ohm resistor on the knock sensor sub-harness. (I think 1 mega ohm?) easy peasy and really cheap.

js959 · 12-09-2009, 11:02 PM

finally! haha thanks homer. i've been searching without much luck.

hey homer, not to sound like a newb (i pretty much suck with wiring/electronics) but how exactly did you rewire it with what you bought? do i have to ground the drain wire? or the non-signal wire?(sorry for lack of better wording) thanks again.

Homer_Simpson · 12-10-2009, 12:01 AM

Quote:

Originally Posted by js959

finally! haha thanks homer. i've been searching without much luck.

hey homer, not to sound like a newb (i pretty much suck with wiring/electronics) but how exactly did you rewire it with what you bought? do i have to ground the drain wire? or the non-signal wire?(sorry for lack of better wording) thanks again.

IIRC, the drain wire is eventually spliced in with all the other drain wires and grounded. I would recommend that you unwrap the harness and have the new section of the shielded wire spliced in as close to the ECU plug as possible. You'll understand once you unravel the harness or trace the wire for the knock sensor. Good luck.

johngriff · 12-10-2009, 12:23 AM

Lowes has shielded wire, and home depot by the foot.

Resistance test the wire from KS connector to ecm connector, that should make you want to replace it.

You can unlock the ECM connector to remove the pin, but rebuilding the crush pin is a little tricky, so you might be better off doing a good solder job. Bad job.. well.

js959 · 12-10-2009, 12:10 PM

wow.. i feel like such an idiot cuz i don't really know sh*t about wiring lol. but i'm getting what yall are saying now.

i've got the pin out of the ecu plug and the pin out of the knock connector, but i don't have any shielded wire, and i'd probably be better off splicing.

johngriff · 12-10-2009, 12:42 PM

No, don't. Electrical isn't something that is taught in grade school.

It is easy to learn, if you put the energy in though.

Homer_Simpson · 12-10-2009, 03:15 PM

Quote:

Originally Posted by johngriff

No, don't. Electrical isn't something that is taught in grade school.

It is easy to learn, if you put the energy in though.

At least you're trying to do it. I never wired anything in my life and I did the SR wiring in my S14. Fired up with the first try. You learn a lot by trying. Just gather as much information beforehand as you can before tackling the job.

Rabboni · 12-10-2009, 04:24 PM

If i were you i'd splice the shielded wire in. Just make sure you leave enough on both ends to solder the wire in comfortably, and with room for movement. Also make sure the shielding wire is grounded on both ends to a tested, good ground. To use new pins requires special crimping tools and the correct pins from the manufacturer. I dont know about the pins, but i know the special crimping tool is expensive.

js959 · 12-10-2009, 09:30 PM

yeah like i said, i think i'd be better off splicing lol.

so, another question that makes me sound like i don't know squat about anything... i've read different stuff about the shielding wire. how far does the shielding wire acually go? and what does it ground to?

Rabboni · 12-10-2009, 09:48 PM

Shielding wire goes the entire length of the wire. It grounds on both ends to any good chassis ground. From what i understand you can buy shielded wire with the shielding built in, so all you have to do is ground both ends of it and make sure its not shorted to the signal wire. Not to hard to accomplish.

js959 · 12-10-2009, 10:28 PM

alright this is making alot more sence now. i'm just gunna have to order what homer posted, cuz i've checked alot of places around here like home depot, different radio shacks, even an electric supply store, which i was so certain they would have what i'm looking for, but the dam guy had no clue what i was talking about. so yeah, thanks again for all the help guys i really appreciate it.

12-05-2009, 12:37 AM	#1
js959 Join Date: Jan 2009 Location: Chesapeake, VA Posts: 41 Trader Rating: (3) Feedback Score: 3 reviews	knock sensor wiring hey everyone. my car was running bad for a while then i replaced my knock sensor and it ran like complete crap. so i found the black wire on the chassis side harness before the sub harness going the KS was broke so i soldered that back together. it acually ran a tad bit better. NOW, here is what confuses me a little, i wrapped some of the wiring before the connector that connects to the sub-harness connector in electrical tape, and it ran a little better. so i wrapped it in even more electrical tape and it ran a little more better. does anyone know what that exactly means? thanks.

12-07-2009, 07:25 PM	#7
Rabboni Zilvia Member Join Date: Aug 2009 Location: Fairfield, CA Posts: 230 Trader Rating: (0) Feedback Score: 0 reviews	Just looked up the knock sensor in the fsm. It only has one wire coming from the PCM and that goes to the knock sensor, then grounds through the knock sensor body. The other wire is a shielding wire to prevent Electro-Magnetic Interference. Spec for testing is Terminal A of the knock sensor connector should have 500 to 620 Kilo-ohms resistance to ground. The shielding wire should have almost no resistance to ground. __________________ Baling Wire-The Duct Tape Of Champions

12-10-2009, 12:23 AM	#15
johngriff Post Whore! Join Date: Jun 2004 Location: Long Beach, CA Posts: 4,103 Trader Rating: (4) Rides Gallery: johngriff Feedback Score: 4 reviews	Lowes has shielded wire, and home depot by the foot. Resistance test the wire from KS connector to ecm connector, that should make you want to replace it. You can unlock the ECM connector to remove the pin, but rebuilding the crush pin is a little tricky, so you might be better off doing a good solder job. Bad job.. well. __________________ [email protected]

12-10-2009, 12:42 PM	#17
johngriff Post Whore! Join Date: Jun 2004 Location: Long Beach, CA Posts: 4,103 Trader Rating: (4) Rides Gallery: johngriff Feedback Score: 4 reviews	No, don't. Electrical isn't something that is taught in grade school. It is easy to learn, if you put the energy in though. __________________ [email protected]

12-10-2009, 04:24 PM	#19
Rabboni Zilvia Member Join Date: Aug 2009 Location: Fairfield, CA Posts: 230 Trader Rating: (0) Feedback Score: 0 reviews	If i were you i'd splice the shielded wire in. Just make sure you leave enough on both ends to solder the wire in comfortably, and with room for movement. Also make sure the shielding wire is grounded on both ends to a tested, good ground. To use new pins requires special crimping tools and the correct pins from the manufacturer. I dont know about the pins, but i know the special crimping tool is expensive. __________________ Baling Wire-The Duct Tape Of Champions

12-05-2009, 12:57 AM	#2
js959 Join Date: Jan 2009 Location: Chesapeake, VA Posts: 41 Trader Rating: (3) Feedback Score: 3 reviews	also, i tested the signal wire continuity, and it was fine. and it has no continuity to ground. the black wire has good continuuity to ground. i have an idea or two, but i want to see what yall think.

12-06-2009, 05:21 PM	#3
shinobis13hb Zilvia Addict Join Date: Dec 2008 Location: la crescenta Age: 35 Posts: 982 Trader Rating: (12) Feedback Score: 12 reviews	more tape =))) lol its a ground wire?? correct?

12-06-2009, 08:23 PM	#4
js959 Join Date: Jan 2009 Location: Chesapeake, VA Posts: 41 Trader Rating: (3) Feedback Score: 3 reviews	haha, the wires have a good amount of tape around em now. the FSM says black wire is ground, but i've read other threads about it saying it's a shielding wire, it's kinda confusing to me. the white wire is the signal wire. i really want to rewire it but i'm not sure if i'd have to insulate the signal wire alot, like it is already. and if it's possible to take the pin out of the ecu connector or just cut and splice near the ecu connector.

12-06-2009, 09:10 PM	#5
Homer_Simpson Zilvia Addict Join Date: Jun 2008 Location: Back in the Bay! Posts: 619 Trader Rating: (11) Feedback Score: 11 reviews	The wire for the knock sensor is a shielded wire, it has a foil-like layer around it to insulate against electrical noises. Get some shielded wires and replace the old hacked up wire.

12-07-2009, 09:16 PM	#8
js959 Join Date: Jan 2009 Location: Chesapeake, VA Posts: 41 Trader Rating: (3) Feedback Score: 3 reviews	i really want to rewire it, but i can't find any shielded wire. does anyone know where i can get some? or a site to order from?

12-08-2009, 10:31 PM	#9
js959 Join Date: Jan 2009 Location: Chesapeake, VA Posts: 41 Trader Rating: (3) Feedback Score: 3 reviews	is this a straight up rewire? or is there anything special that i should know about?

12-09-2009, 08:23 PM	#10
redline racer510 Zilvia FREAK! Join Date: Dec 2007 Location: EARFF(earth for you idiots) Posts: 1,072 Trader Rating: (1) Feedback Score: 1 reviews	man i think finding sheilded wire is going to be a bit tricky, try searching online, or try asking the dealership if they can get you some bulk sheilded wire.

12-09-2009, 10:03 PM	#12
nrmskate Zilvia Addict Join Date: May 2008 Location: IL Posts: 979 Trader Rating: (9) Feedback Score: 9 reviews	I havn't read through all the post's, but, in order to just bypass the knock sensor and avoid getting an CEL, is running a ohm resistor on the knock sensor sub-harness. (I think 1 mega ohm?) easy peasy and really cheap.

12-09-2009, 11:02 PM	#13
js959 Join Date: Jan 2009 Location: Chesapeake, VA Posts: 41 Trader Rating: (3) Feedback Score: 3 reviews	finally! haha thanks homer. i've been searching without much luck. hey homer, not to sound like a newb (i pretty much suck with wiring/electronics) but how exactly did you rewire it with what you bought? do i have to ground the drain wire? or the non-signal wire?(sorry for lack of better wording) thanks again.

12-10-2009, 12:10 PM	#16
js959 Join Date: Jan 2009 Location: Chesapeake, VA Posts: 41 Trader Rating: (3) Feedback Score: 3 reviews	wow.. i feel like such an idiot cuz i don't really know sh*t about wiring lol. but i'm getting what yall are saying now. i've got the pin out of the ecu plug and the pin out of the knock connector, but i don't have any shielded wire, and i'd probably be better off splicing.

12-10-2009, 09:30 PM	#20
js959 Join Date: Jan 2009 Location: Chesapeake, VA Posts: 41 Trader Rating: (3) Feedback Score: 3 reviews	yeah like i said, i think i'd be better off splicing lol. so, another question that makes me sound like i don't know squat about anything... i've read different stuff about the shielding wire. how far does the shielding wire acually go? and what does it ground to?

12-10-2009, 09:48 PM	#21
Rabboni Zilvia Member Join Date: Aug 2009 Location: Fairfield, CA Posts: 230 Trader Rating: (0) Feedback Score: 0 reviews	Shielding wire goes the entire length of the wire. It grounds on both ends to any good chassis ground. From what i understand you can buy shielded wire with the shielding built in, so all you have to do is ground both ends of it and make sure its not shorted to the signal wire. Not to hard to accomplish. __________________ Baling Wire-The Duct Tape Of Champions

12-10-2009, 10:28 PM	#22
js959 Join Date: Jan 2009 Location: Chesapeake, VA Posts: 41 Trader Rating: (3) Feedback Score: 3 reviews	alright this is making alot more sence now. i'm just gunna have to order what homer posted, cuz i've checked alot of places around here like home depot, different radio shacks, even an electric supply store, which i was so certain they would have what i'm looking for, but the dam guy had no clue what i was talking about. so yeah, thanks again for all the help guys i really appreciate it.

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