CPS replacement shielded harness wire?

[CyFi6]

My CPS wiring is shot where it meets the CPS and i plan to run a new length of wire from about a foot back in the harness. I noticed the stock CPS wiring has a shielded outer insulation, and i was wonder where i could buy some 4 wire shielded wire that would be suitable for this application. I figure this section needs the shielding most considering how close it runs to the coil packs. Thanks for any info or tips.
Does anyone know the diameter of the wires? Would something like this suffice or is it too light duty to stand the heat and abuse?
http://www.stewmac.com/shopby/item/...e&utm_medium=shopping&utm_campaign=2010-11-gp

 

[Kai]

Take a picture - lemme see how borked this wiring is. Mine was borked as well, but, it had a little snipped off, and was re-pinned - checks out fine.

 

[CyFi6]

I cant get any pics now because for the time being I heatshrinked everything- the insulation on the wires basically turned to plastic, cracked, and the wires were shorting to the grounded shield wiring and the car would die. The wires are extremely hard and even when I cut about an inch back and stripped it, the wire strands are very dirty/contaminated and solder doesnt even like to stick to them. Looks like moisture traveled up the insulation a bit. I put new pins/connector on it because I thought that was the cause of my intermittent cps problem, but it was because of the shorting after all.

 

[Kai]

Well, on my harness, it's just wrapped, not shielded. Best thing to do - would be to remove the whole harness from the bay - strip off all the old wrapping, pick out the CPS wires and de-pin them from the ECU connector. Then take a crimp tool, a bag of sumitomo MT series pins, and 4 lengths of automotive wire in the correct gauge (16 or 18 gauge, iirc), and wire in a whole new section of wire, with the correct pins on each end. You could splice i guess, but i'd rather use a fresh run of cable, than 20+ year old baked copper. It's not as hard as it looks

 

[CyFi6]

Ya I understand what your saying, but I think I would replace the entire harness before I went in and did all that, its not in the best shape. Problem is that all 4 of the CPS wires have a shielded insulation around them to protect them from interference, so I cant just replace them with plain wires run through the harness. I will try to snap a pic of it or find a pic to show you what I mean. Are you sure that yours are not shielded? Right about where mine enters the harness above the valve covers is where the shielding starts.

 

[max-89supra(t)]

My CPS wiring is shot where it meets the CPS and i plan to run a new length of wire from about a foot back in the harness. I noticed the stock CPS wiring has a shielded outer insulation, and i was wonder where i could buy some 4 wire shielded wire that would be suitable for this application. I figure this section needs the shielding most considering how close it runs to the coil packs. Thanks for any info or tips.
Does anyone know the diameter of the wires? Would something like this suffice or is it too light duty to stand the heat and abuse?
http://www.stewmac.com/shopby/item/...e&utm_medium=shopping&utm_campaign=2010-11-gp

those wires are too thin, they offer 28 and 26 gauge wires (way too thin), factory is 16 or 18 gauge

 

[Kai]

....i said what the gauge was in my earlier post.

Anyway - why not refurb your harness? Might as well give it a proper going over, all the connector housings should still be available from Toyota, and pins aren't hard to come by

 

[jetjock]

What Kai said. I use shielded MIL-C-27500 for that kind of work. Overkill but I have plenty lying around. You could also run a new CPS cable directly to the ECU ala the knock sensor rewire. If you won't spring for 27500 something like twisted paired Belden #8723 will suffice. Run it along the right fender and into the firewall grommet if you don't want the hassle of tracing the harness.

 

[Kai]

I was just going to use this stuff:

Thinwall cable 1.0mm.
Operating temp -40 to +105 deg.C. Maximum working voltage 60v.
Nominal current rating 16A. (Derate for long lengths)
Resistance per metre at 20 deg. C: 0.0185R.
Plain copper conductors (32/0.20mm).
Maximum overall diameter of cable 2.1mm.
Sold in multiples of 1mtr.
Price per meter: £0.25 (£0.29 Including VAT at 17.5%)

 

[IJ.]

Do you only ground one end of the shield with the stock ECU?

 

[Kai]

It's all you need with the knock sensors - they're 1 pin, the shield is grounded at the ECU end only.

 

[jetjock]

Kia: It really ought to be shielded or at least twisted pairs. If you keep it away from the ignition secondary I suspect it'll be OK though.

Ian: Yes. Generally speaking that's the case unless you're dealing with higher frequencies. For example with RF you would ground both ends.

 

[IJ.]

Thanks Gary, was just curious as it's common practice with aftermarket ECU's.

 

[Kai]

Well, the stock stuff isn't shielded, from what i can see - just covered in PVC sheathing :/

 

[jetjock]

Kai: Knock, CPS and O2 are shielded on USDM cars. At least that's been my experience. It's also shown in the EWD. I'm puzzled as to why UK cars would be different.

Ian: You're welcome. With the age of these car reaching a point where it appears mainly 12 year olds are working on them I'm glad to still be of occasional help to someone

 

[Kai]

RHD wiring harness differs in a few ways...O2 isn't shielded for sure - again, just PVC sheathing. The only thing that's shielded, is the knock sensors. I'd hazard a guess as it being something to do with not needing to be FCC certified or something?

 

[grimreaper]

What Kai said. I use shielded MIL-C-27500 for that kind of work. Overkill but I have plenty lying around. You could also run a new CPS cable directly to the ECU ala the knock sensor rewire. If you won't spring for 27500 something like twisted paired Belden #8723 will suffice. Run it along the right fender and into the firewall grommet if you don't want the hassle of tracing the harness.

I only see the 8723 in 22awg and smaller. Will the smaller wires have ANY effect on the signals?
Beldon #8760 appears to be identical in shielding except its 18awg and only has two wires. You'd have to double up on it

 

[jetjock]

22 is ok. I wouldn't go smaller though, not so much because of electrical issues but because smaller is delicate. That said it's likely Belden makes something similar in a thicker gauge. If not I'm sure others do. Alpha or Carol comes to mind.