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stock ECU harness concerns

 
Old 01-07-2018, 09:53 PM
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Default stock ECU harness concerns

Hi all,

I was working away on installing my mega squirt today, when I got the stock ECU removed I have some concerns with the wiring, it looks as though someone has spliced some things together at some point. I've taken some pictures to see if I can get some help on what's been done and if I need to try and fix this before plugging in the mega squirt ecu

can anyone suggest what I should do here...
Attached Thumbnails stock ECU harness concerns-img_3689.jpg   stock ECU harness concerns-img_3690.jpg   stock ECU harness concerns-img_3691.jpg   stock ECU harness concerns-img_3692.jpg   stock ECU harness concerns-img_3693.jpg  

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Old 01-07-2018, 11:03 PM
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I'd resolder that with new wire and heat shrink...clean it up. That's all.

Last edited by thirdgen; 01-07-2018 at 11:58 PM.
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Old 01-07-2018, 11:13 PM
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Ok so is that how it should look?

it looks to me like someone has cut and tapped some wires together that don't normally belong together.
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Old 01-07-2018, 11:59 PM
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I doubt it, it looks like ****. I love repairing stuff like that, and I'm good at it. Where are you from?
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Old 01-08-2018, 12:21 AM
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b.c canada.

I just don't want to mess up the new eco if something is wrong. I could fix it up but the stripped wires that connect to each other randomly is whats concerning.
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Old 01-08-2018, 12:51 AM
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Couple more questions , what year is the car , was it running on the stock ECU previously, Was running normally ie no check engine light ?
Going from memory and the wire colours on my car , the wires that have been hacked look like the TPS and the O2 circuits.
Id start with getting a wiring diagram (year specific to your year of car ) figure what's been modified and make sure it's going to the correct pins in the connector. If you let the smoke out of your new MS , it's not going to work very well Fredb .
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Old 01-08-2018, 12:58 AM
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On closer examination, some of that looks like a pair of shields going to ground. Get a wiring diagram and check the colours. If I remember correctly , my CAS signal was shielded as was something else that I don't recall. Fredb
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Old 01-08-2018, 01:12 AM
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Thanks Fred,

Car was running great on the stock ECU, it's a 1990.

I've been searching for a while and can't seem to find a wiring diagram, not one I understand anyways.

I just went to look at the car again, there is an orange wire and a grey wire, both of those have the exposed wire coming out of them, as you mentioned it looks like maybe shields?

the o2 sensor wire has been changed, perhaps thats it?
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Old 01-08-2018, 03:51 AM
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if stock ecu was fine, and you use a PNP, there should be no differences, right?
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Old 01-08-2018, 09:34 AM
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My car is a Canadian 1990 as well , I'll check my car and wiring diagrams and get back to you after work today. If it was working fine before , I be inclined to make sure everything is insulated and call it good. Fredb
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Old 01-08-2018, 10:04 AM
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The bare conductors joined in a crimp to the black wire are just shields and by the looks of the crimp, factory.

The soldered butt connections do not look like factory. I just disassembled my entire OEM harness and did not find one soldered connection (as it should be)

Remove the soldered bit and re-splice with a quality butt splice and the correct crimping tool.

In absence of the correct tools or butt splices, re-tape/shrink and continue on as normal.
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Old 01-08-2018, 10:05 AM
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the red wire is the AFM signal, and the red/blue is the o2 signal. some owner probably had some piggyback on it at one point and cut both wires and has since reversed it. the shielded grounds are oe.

wrap it back up and move on.


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Old 01-08-2018, 10:12 AM
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thank you all so much for the help! I'll leave the soldered wires and tape it back up, again thank you!
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