Quote:
Originally Posted by gmercoleza
TRY THIS (from my 300E log): << cleaned throttle position sensor and lubed with wd40 - hunting idle is gone. >>
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A good suggestion, although I would recommend Caig MCL over WD-40 for this application. My biggest problem with WD-40 as an electrical contact cleaner in a moving part (potentiometer) is its affinity to collect dust and dirt.
Cleaning moving electrical moving parts can be a bit tricky, there is a thin line between ineffective cleaning, and washing away necessary lubrication. Often the lubrication in pots is a light grease, and WD-40, MCL, or any contact cleaner is going to tend to wash away that grease and replace it with a much thinner oil. Problems begin when the contact cleaner dries out, and now the metal wipers of the pot are in direct contact with the carbon traces, and now wear begins. Friction goes up after the oil starts to dry, and often the pot shaft will begin to stick. Additionally, the lack of lubrication between the wipers and traces begins to wear out the carbon traces, and this is when the electrical characteristics begin to degrade.
Ideally, one would prefer to first wash away the previous grease along with all the dirt accumulated over the years, and then replace the heavier grease after the solvent has dried. Some contact cleaners have silicones in them, and these are often enough to provide the necessary lubrication. But really, applying a grease afterwards is the way to go.
Just remember, if you spray out a pot and work the shaft several times and the action goes from smooth to crunchy, you know what has happened. You need to spray it out some more to remove the last traces of dirt, and then re-lubricate with something a bit thicker.
It is possible to destroy a pot by trying to clean it out, I have seen it happen. The cleaner washes all the grease away, the wiper hits a piece of dirt, except now without grease, the piece of dirt catches the wiper arm and bends or breaks it......