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Ultrasound component cleaning

EFI Wiring Fundamentals

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Discussion and questions related to the course Motorsport Wiring Fundamentals

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Hi guys,

I want to modify an OEM harness, which would be wise to clean before use. Especially connector bodies etc.

I have access to an Ultrasound clearing machine, but i have no experience with it, so i would appreciate any input regarding details like cleaning solution, suggested cleaning times and so on.

Is it advised to clean the connectors assembled, if i don't plan to de-pin them anyway?

Is it necessary to use a special solution for cleaning, or is there a home-made option up to the task?

Is it safe to use the same cleaning solution for plastic bodies, metal contacts and cables, or a special is needed for all?

I have found various "hobby workshop" solutions, but they don't specify whether it's safe to use on plastic parts, and many solutions for jewellery, watches and glasses.


I haven't personally cleaned connectors with an ultrasonic cleaner however Zac did on one of his own personal project cars with great results. I can't be more specific about the process unfortunately however I'd recommend depinning them before cleaning them.

Thanks for the input Andre.

I am thinking of skipping the de-pining, for reliability issues, for sections of the harness that i will keep. I agree that the cleaning will be better on disassembled bodies, it will be again dirty soon anyway (gravel rallying...)

I am focusing on a "general workshop purpose" solution for a trial and I will keep you posted.

My main concerns are "free" dirty being stuck around the terminals or wire seals and any impact on the pins plating, since it is generally advised to avoid ultrasound cleaning on (nickel) plated parts.

Trials it is then! i will keep you posted.

By the way, I can remember Zac talking about this in one of his videos, but I cannot find which was it.

Any hints?


I use an ultrasonic cleaner in my shop for things such as this. I have found distilled water and a little distilled vinegar work very well on degreasing and cleaning parts without eating into anything. I have only used it on throttle body and carb parts tho so I'm not sure about the nickel reacting with the acid in the vinegar. I'm going to be doing this as well but will be depinning everything before cleaning.

I Found both the webinar where Zac is referring to the process: https://www.hpacademy.com/previous-webinars/180-which-crimp-tool-should-you-use/

As well as another forum thread for this purpose: https://www.hpacademy.com/forum/efi-wiring-fundamentals/show/cleaning-connector-housings

It looks like a general purpose cleaner will do.

I will keep you posted once I get to it.

So, it looks like it actually works!

I got on ebay a used ultrasonic device of probably the lowest possible quality. That costed around 20€

I got this detergent: https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.de%2Fulk%2Fitm%2F362451667291 and used it as suggested 1:20 with warm distilled water. (Distilled, just because of the high calc in tap water)

I put in de-pinned oem nissan connector bodies, locking tabs, rubber seals and some pigtails to try the terminals too.

I did run 6-7 10min cycles (maximum of the machine) throughout 24h and just letting it all soak for the rest of the time.

I am not completely convinced whether the ultrasound or the soaking did the job, but it worked.

Most of the dirt was detached, or was rinsed off afterwards. Worst case, it was just wiped off. Seals looked fine and the terminals look also intact. It can be that the wire part of the pigtails became a bit more rigid, but it was a used harness anyway.

See attached images for details.

Attached Files

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