not tuning, vacuum modulator...
06-21-2007, 08:35 PM
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'86 300e
not tuning, vacuum modulator...
After i replaced the coolant temp. sensor, the cutting out problem disappeared but shortly after i started fouling my no.6 plug - whatthef***??
I guessed that the mixture may have been riched up in a previous tune-up because one of the effects of a faulty temp. sensor would be to lean off the mix inappropriately. Then my transmission ran out of fluid. At this point i decided to call the experts - when i mentioned the trans drying out the first thing he asked was "is it blowing smoke?" i said yeah, and fouling plugs...he said its the vacuum modulator diaphragm - it gets a pinhole and starts sucking trans fluid into the engine, hence the smoke fouling and dry tranny
So - for your information, car starts blowing white smoke, transmission starts running fluid down with no visible external leaking = vacuum modulator diaphragm worn out - file it away 300e drivers, it'll visit you sooner or later.
I guessed that the mixture may have been riched up in a previous tune-up because one of the effects of a faulty temp. sensor would be to lean off the mix inappropriately. Then my transmission ran out of fluid. At this point i decided to call the experts - when i mentioned the trans drying out the first thing he asked was "is it blowing smoke?" i said yeah, and fouling plugs...he said its the vacuum modulator diaphragm - it gets a pinhole and starts sucking trans fluid into the engine, hence the smoke fouling and dry tranny
So - for your information, car starts blowing white smoke, transmission starts running fluid down with no visible external leaking = vacuum modulator diaphragm worn out - file it away 300e drivers, it'll visit you sooner or later.
06-21-2007, 08:57 PM
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2011 VW cc, 2004 ML350
I remember this problem from when I worked in a garage back in the 80s. We had two mid 80s GM products with that problem in just a few months time. Hadn't ever seen it on an MB, though.
