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Discussion Starter #1 (Edited)
Hello everyone,

I'm keeping on with my 89 Turbo M/T that I pulled out of a yard for $500. After replacing both sensors to fix code 52 (shoutout to my dad's cousin who has a lift in his garage, that rear sensor was a bitch) code 52 came back next drive. I'm assuming it's wiring at this point. I'm planning on rewiring, but is it worth it to go all the way back to the engine harness with new wiring? I want to avoid having new wire spliced onto old wire, you know? If so, I'm thinking about pulling the harness and refreshing it a bit while I'm there. I'd like to label things, put new loom on the bundle coming across the firewall, stuff like that.

Does what I'm saying make any sense? Has anyone else done a pull-and-refresh on their existing harness? If YotaConnectors wasn't essentially defunct at this point, I'd consider getting the guy to refresh my harness. Also, as for the knock sensor, will I run into trouble if I go with coax wire like other people have if I'm running it back to the harness? Do I need to splice down to something smaller anyway?

Thanks.

Edit: I think I've done enough reading to be able to wire the knock sensor wire all the way to the ECU. I'm going to try to place a new pin to the ECU on the new wire for both. Is there a size or something I should be looking up for ECU harness pin?
 

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1989 Supra Turbo TT
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I'm still learning about supras myself, but in my experience with some European cars I would use the same gauge wire when trying to replace. Apparently resistance matters. I've had a knock sensor go bad in a few of my cars. Does your supra run even with the code? My other cars were completely immobalized when the sensor went.

You may not need to replace the whole thing. If you visually inspect and find a break in the insulation, you could just bypass that section. Depending on where you live or how close the wire is to heat though, these old wires could have many cracks in the insulation throughout. I had a small break within the insulation for an ABS speed sensor. Quick fix once I found it. But it could be as bad as this... wiring for my headlights in my other car...
257501


Good luck. Hope this helps and you get it straightened out.
 

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To my luck after a week or 2 of daily driving my 90 turbo code 52 showed its head. I did mine backwards replaced wires first now ordered new sensors fingers crossed this fixes the code..
 

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I wish I'd seen these posts sooner!

99% of the time, the knock sensors are just fine and the issue is the wiring, specifically, the wiring deteriorates right at the plugs that snap into the knock sensors.

The knock sensors need shielded wiring so you can't just splice in regular wiring and hope it works. There's an old SOGI trick that uses Coaxial cable to rewire the knock sensors because it's cheap, shielded, and widely available. But it looks like shit.

These days Yotaconnectors offers a nice rewire kit and I emphatically recommend it:

Also, buying correct crimping tools and components is an initial expense none of us enjoy, but it makes every future wiring project overwhelmingly easier and more effective. Buy the right tools to get it done right the first time and never worry about it again!
 
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