Lifetime Premium Member
Date registered: Jul 2009
Vehicle: '92 300TE 4matic 280,000miles, '92 300TE 4Matic 'Ice Blue Metalic' 101,000miles
Mentioned: 2 Post(s)
Quoted: 498 Post(s)
There are various ways to remove that steel ball in the tower. I've read quite a few different approaches. The dealer must have done it in my white TE and this new-to-me TE had it already done by someone. I know that in my parts box is a small tower with a gasket, new. I don't remember how or why I acquired that. It would seem to me if the tower unscrews that easily, the attack would best be performed off the car.
In any event, a lot of people confuse how Mercedes chose to do the duty cycle, i.e., the percentage of the cycle they used during the pulse period. Even people buying duty cycle meters get confused at what they are looking at. I just use a big analog meter on volts, hooked up to #2 and #3. I figured out what my cycle voltage was (with a digital VOM) and did the formula. My voltage is 13.7 found between #2 and #6, if memory serves me correctly (that voltage never seems to change). I take the voltage I found between #2 & #3 (which averages 7 volts) and divide that by 13.7.....I get .51094891. Then for percentage, I do this; 1.0-.51094891=49%
Ideally, my needle will swing from 6.5 to 7.5 with 7 volts as the median average. When your needle swings like this, it indicates your O2 sensor is at least working. Cars with well worn AF potentiometers will not be able to hold your adjusted duty cycle reading for very long. These instruction are for the M103.
Last edited by Real1shepherd; 10-15-2018 at 10:57 AM.