View Single Post
      08-27-2015, 03:04 PM   #19
alexwhittemore
Lieutenant Colonel
111
Rep
1,951
Posts

Drives: 2009 Crimson 328i
Join Date: Oct 2012
Location: Los Angeles

iTrader: (0)

Quote:
Originally Posted by speedball73 View Post
I'm worried that the resistance through the corroded external connector is causing the periodic drop of voltage to the Valvetronic/DME. You can't see it in the photos, but the plastic of the external side is completely cracked from the expansion caused by the corrosion underneath the plastic.

Going to try the wreckers tonight....
it could very well be corrosion related, but the mechanism of action is much less straightforward. Every junction has a "junction resistance" as a result of real-world interface effects (like surface roughness resulting in less than 100% contact on an otherwise flat, even interface, surface oxidation, and so on). Corrosion will definitely change that for the worse, but if you're noticing periodic dropout, it'll be because vibrational or thermal effects result in the junction briefly opening then settling back into a more favorable state than before. It's possible a high resistance is resulting in current spikes dropping supply voltage below some threshold, but it'd be surprising to see complete cut out in that case, rather than oddities in functionality like screens cutting out, audio skipping, warning indicators flashing, that kind of thing.

Anyway, my point is, it's definitely SAFER to completely replace the hardware, but if it truly is a problem of junction corrosion, cleaning the corrosion off should absolutely be sufficient. Even if the surfaces aren't mechanically as ideal as they previously were due to pitting and that sort of thing, they'll be plenty good enough.
__________________
Appreciate 0