Tech Article: Clean up those Corroded Connections
by Marc Sayer
Use white vinegar. Soak the connectors in pure white vinegar (overnight is best but even a couple hours will help). Then rinse them thoroughly in water to neutralize the vinegar. Then spray them with either alcohol or some proprietary electrical contact protectant. This last step is to displace any water and ensure that they wonít start corroding right away again, so the proprietary stuff would work best, but alcohol will mix with and carry off the water as it evaporates. Blowing it off with clean compressed air will help speed this process up but even without, it will be dry in a few minutes.
The acidity of the vinegar will eat away any corrosion on the contacts, without doing any damage (donít use any acids that are very much stronger than this). The water will neutralize the acidity and wash the vinegar away, and the alcohol or proprietary product will remove the water and dry everything out (the proprietary stuff usually has some lubricants and protectants in it too, which is why it works even better than plain alcohol).
Tape up the plug portion real well with electrical tape so that you can fill the "plug" with vinegar without it all draining back out. As for the harness plugs, simply undo them all, pull the wires back a bit so you have enough play to work them into position (you will need to undo some of the harness "clamps"). Then position them so that all the plug ends are immersed in a container of vinegar. To keep the plugs completely immersed you will probably need to tape the wire to the container. You may also need to weight the container to prevent it from tipping over.
Any way this is an easy method you can perform with simple household products and it works great. It not only works for FI contacts, you can use this for any automotive electrical contacts. The advantage to this, over solutions involving abrasives such as sandpaper, is that this will not harm any plating that might be on the contacts and so will not reduce the original corrosion protection (if any) as badly as abrasives will. It also gets all the corrosion, even in areas where you couldnít reach with sandpaper
PS - Donít forget to do all the sensor plugs such as water/cylinder head temp, etc.