duty cycle 103 engine

[lee polowczuk]

What tools do you need to test/read duty cycle on this engine?

[Mike Murrell]

Tons of yack on the subject at this forum check archives.

For starters - you need a voltage-ohm meter that reads duty cycle. Sears has one for a reasonable price. Mentioned here in numerous threads

Also - go to google and key in "duty cycle mercedes m103"

Youtube video on the subject - cannot attest to its validity.

[JamesDean]

basic multimeter will suffice..

@ X11 connector (round guy typically found on drivers fender under hood on 201's)
duty cycle = (voltage at pin 3 / battery voltage) X 100
(connect meter ground to pin 2)

this will give you an approx. value for duty cycle.

Should be 70% Key on, engine off for federal. 85% for cali.

If its a fixed voltage after say 30-40 seconds of running, then its throwing a fault code and something is broken/out of adjustment/etc

[lee polowczuk]

[QUOTE=JamesDean;2637882]basic multimeter will suffice..

@ X11 connector (round guy typically found on drivers fender under hood on 201's)
duty cycle = (voltage at pin 3 / battery voltage) X 100
(connect meter ground to pin 2)

this will give you an approx. value for duty cycle.

Should be 70% Key on, engine off for federal. 85% for cali.



that's almost exactly what i was looking for.... the final piece is "what setting do you set the multi-meter on?

I am completely ignorant when it comes to electrics

[JamesDean]

set it to DC Volts.

[lee polowczuk]

thanks, .....like i said

[Cal Learner]

Lee, the equation JamesDean gave has a small error. That would actually give you the complement to duty cycle. Set DMM to volts, take the reading, and put that reading into the following in place of V{pin 3}:

Duty Cycle = [1 - (V{pin 3}/V{max})] x 100%

[JamesDean]

Cal, you are correct. My apologies, I'd forgotten about that.

Here is some more information on the procedure:

http://www.landiss.com/mixture.htm