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Discussion Starter · #1 ·
It may be a dumb question, but why do we use coax wire for the rewire mod?
Looking at the originals, I didn't get the impression that Toyota used a shielded wire. Is this to block electrical interference from other sources?

Anyway, I ask because after replacing my radiator with a larger one, I started getting the code 52. I already have the rewire mod in place using that coax, and I really don't know why the car would suddenly start throwing knock codes, just because I replaced the rad. After all, I didn't go anywhere NEAR the wiring or knock sensors while doing this. I've cleared the codes, checked to make sure the connectors were secure, but the code keeps coming back. If anyone has any suggestions, lemme know- I did read the posts on code 52's, but no luck. My plan is to replace the replacement KS wiring...

:rolleyes:
 
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slowly giving up...
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because coax wire is shielded. shielded wire prevents electrical "noise" from interrupting the KS signal, hence causing code 52.

code 52 is caused by two things:
1) bad wiring (most common cause)
2) a bad KS.

-shaeff
 

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Discussion Starter · #4 · (Edited)
I've never torn into USB cable-
How many signal wires does it have inside- more, than one, yes?

PS- intersting thing, and some of you may have already known this:
Looking up the part numbers for the knock sensors through certain online auto parts stores, The part number for the Supra's knock sensors is the same as almost every 4 and 6 cylinder Toyota from the 80's through present. Now that doesn't help much in terms of purchase price, but it would certainly make it WAY easier to find a used one at a junk yard!
Just thought I'd share.
 

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JE, AEM, OS Giken'd 7M
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You need one signal line and one ground(shield), hence Coax is a common choice. Good shield, single solid conductor in the middle. It's also very common and cheap where as USB 2.0 isn't nearly as much so.

/did a KS Re-wire last night.

Either way, you land the signal line at the sensor plugs themselves then take the shield to a ground. Then run the coax/whatever along the firewall, then through the firewall/ECU harness boot. Under the dash, there are two wires, I believe they're the top left, or bottom left of the Middle plug (on an 87-88) they look distinctly different from the other wires in the harness. Measure 'em a few inches back, cut & strip 'em. Then take your coax, cut back the shield and the insulation, slide on some shrink tube, solder one coax to one KS line, and the other to the other line. Heat the shrinktube. Check the engine bay, make sure you've taken the shield to a good solid ground connection and enjoy, you should be good to go. For me, I took some extra wire, and soldered that to the Coax's shielding, then took it to the negative terminal itself. Works 202002000x better and no Code 52. Yay for timing.

If you look at the factory wire that's used, in the engine bay, it's brown. Once you cut it, you'll notice the brown was just an insulator covering a shield, there's another wire in it that's see-through which carries the actual signal.
 

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Thread reopening lol ok but so on the 7mgte there's two knock sensors were both of the original wires brown?
 
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I too want this reopend! I'm amazed right now at what I'm reading... I'm understanding properly yeah?
I can use a Saturday morning cartoon wire, as my knock sensor communication line.
 

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I too want this reopend! I'm amazed right now at what I'm reading... I'm understanding properly yeah?
I can use a Saturday morning cartoon wire, as my knock sensor communication line.
Yep!

I have done it before. Single plain txl wire. No issues.
Ought to show you how good toyota knock algorithm is.
 

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I don't want an MK4!
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So then is coax just overkill? Or, would it still be what is considered the best option?
 

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it is all about price. If you can source something like guitar wire (which is shielded) for .10/ft vs .40/ft for txl... the answer is rather obvious :)
 

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I don't want an MK4!
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Sorry for being stupid. But what is txl wire and why is price an issue for very short run of wire. I am going to have access to all this stuff on my engine sooner or later and if wire needs to be changed I will have it done.

Please advise.

Thanks

Dan
 

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TXL is just a type of automotive wire. More specifically it's a thin walled, cross-linked polyethylene insulated, copper stranded wire. Temperature rating is -60°F to 257°, so perfect for engine bay use.

Cross-linking is a complicated process that essentially makes the insulation more durable, thus allowing the thinner wall insulation.

If you're on of those folks that doesn't care about spending a little extra on a short run of wire you can go with some flashy ETFE shielded wire (M27500-20SB1T23).
 

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I don't want an MK4!
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TXL is just a type of automotive wire. More specifically it's a thin walled, cross-linked polyethylene insulated, copper stranded wire. Temperature rating is -60°F to 257°, so perfect for engine bay use.

Cross-linking is a complicated process that essentially makes the insulation more durable, thus allowing the thinner wall insulation.

If you're on of those folks that doesn't care about spending a little extra on a short run of wire you can go with some flashy ETFE shielded wire (M27500-20SB1T23).
Thank you,

For such a small run, and for this car I will for sure go with the very best if needed and will probably get it done anyway.

Thank you very much. I hate asking dumb questions about stuff I should know. You guys are cool for not punishing for my lack of certain knowledge.

Dan
 

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Thank you very much. I hate asking dumb questions about stuff I should know. You guys are cool for not punishing for my lack of certain knowledge.
I know people that have made a living in automotive modification/tuning that involved wiring who couldn't tell you the difference between SXL, GXL, TXL, or GPT wire. And that's what the forums are for, gaining knowledge.
 

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It may be a dumb question, but why do we use coax wire for the rewire mod?
Looking at the originals, I didn't get the impression that Toyota used a shielded wire. Is this to block electrical interference from other sources?

Yes they are shielded wires and yes to block any outside interference to the frequency of detonation that the KS listen for. RG6 coax cable has double shields
 
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