Knock sensor and harness problem

[supchef]

Trying to get my 88 turbo on the road, i bought it 4 months ago and have yet been able to see what the potential it has.
It's in a shop in the DFW area the tech is waiting on back order knock sensors, and just descoverd the knock wire is cut somewhere in the harness, along with other misc. wires
He recamends replacing harness. Is there such a thing as a good used harness?
Do I need the knock sensor? The pre owner said there useless.

 

[shaeff]

Trying to get my 88 turbo on the road, i bought it 4 months ago and have yet been able to see what the potential it has.
It's in a shop in the DFW area the tech is waiting on back order knock sensors, and just descoverd the knock wire is cut somewhere in the harness, along with other misc. wires
He recamends replacing harness. Is there such a thing as a good used harness?
Do I need the knock sensor? The pre owner said there useless.

Chances are that the knock sensors are fine, it's just the wiring to them that's damaged (as you stated).

Do this:
http://www.supras.com/06/techcenter/display.php?QID=69

Or find someone to do it for you.

The knock sensors are NOT useless. The previous owner of your car is a half-wit.

 

[Gunnar]

You need the knock sensors or you'll have crappy mileage and less power.
They are rather expensive to replace, so you're cheaper off getting some coax cable and buy 2 sets of used ones. replace the two knock sensors wires with coax ones (keep the connectors).
Remove the glovebox and you'll see the ecu under the top of the dashboard.
Remove the connectors and look for the two transparent wires, those are your knock sensors wires, cut and leave enough to solder them on the center wire of the coax cable.
Now tie together the ground shield of the coax and connect to ground somewhere near the ecu.

You can stick a small wire in the connector itself from one transpartent wire to the other and then you can measure continuity on the knock sensor connectors themselves to see if you are good to go.

Stick the ecu back and start swapping out your knock sensors untill you see a pair that work. No need to drive a round, a good high rev will make the check engine light go on if it's not good.

 

[Boosted Supra]

FYI, that write-up is crap as some people say.

Only ground one end
Splice (chrimp) wires together (do not use spade connectors). I soldered mine with military grade splicers.
If you can find stranded coax cable it'll make your life easier

 

[Boosted Supra]

Is it possible to request a change on that write-up? Can I do one for SM?

 

[Boosted Supra]

Does anyone know who runs/owns supras.com?

 

[supchef]

Thanks, ill forword that to the tech, however I think he will still want to replace the harness. Sounds like that might be the best option.

 

[shaeff]

FYI, that write-up is crap as some people say.

Only ground one end
Splice (chrimp) wires together (do not use spade connectors). I soldered mine with military grade splicers.
If you can find stranded coax cable it'll make your life easier

I wouldn't follow it to the T, but it's a good overview of what needs to be done.

Is it possible to request a change on that write-up? Can I do one for SM?

Does anyone know who runs/owns supras.com?

Try contacting Supracentral on here, if anyone knows, it'll be him. It wouldn't surprise me if he's hosting the SOGI site. Feel free to do a writeup, we can put it in the Articles section.

Thanks, ill forword that to the tech, however I think he will still want to replace the harness. Sounds like that might be the best option.

There's no need to replace the entire engine harness. That would be a waste of both time and money (assuming you're talking about the engine harness)

Rewire the knock sensors, ground them at one end, use new connectors, coax cable, solder or crimp (if using solid core wire, I'd solder) properly, and be done with it. The entire process should take no longer than two hours, and that's including building a sweet knock sensor harness.

 

[Boosted Supra]

I'm not sure if you know shaeff but I'm the author of that write-up.

I wanted to request it be taken down and thrown in the trash, i'll contact supracentral

 

[shaeff]

Ah, LOL. That totally didn't click. I knew that you're Manny, and I knew that Manny wrote it, but I didn't put two and two together. LOL.