Am I doing this right?
Testing and setting the Duty Cycle on a California spec 1988 300TE with Craftsman meter set to %.
Setup...
Key in, Ignition on, diagnostic set to solid LED by holding for 2 seconds and then again.....

Red into red on the meter and black into black or sensor plug on the meter...
Ok, on the car, first I plug the Red lead into socket pin 3 and the black into 2...


Reads 14.8%....????


Reverse the wires... black to 3 and red to 2... reads 85.1% as it should for Cal spec car.




Retest with red removed from 2....... no change?????




Here is the reading using Black to 3 and red to 2... engine warmed up and running nice..... fluctuates about 50% +- 5ish.



Now, is this the right way to do it?
Is that reading about right?

I have not closed the charcoal canister connection because I dont know which one it is!

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2009 Mercedes ML320 Bluetec

That is correct assuming the engine is not fully warmed up on the first pics. See the engine needs to be at 80C for proper setting and checking. Anything before that will be rich due to warmup phase. Also at first before the cat is warmed up to operating temp and the O2 is at operating temp the reading will be wrong. The O2 is ignored at first until it is warm and you will get no fluctuation and a static reading.

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~Jamie
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2003 Pewter C230K SC C1, C4, C5, C7, heated seats, CD Changer, and 6 Speed. ContiExtremes on the C7's.

1986 190E 2.3 Black, Auto, Mods to come soon.....

First photos were with engine off and cold.

Last one is with engine running and 80deg plus showing.

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2009 Mercedes ML320 Bluetec

Correct with engine at operating temp.
But you want the red in pin 3 and the black in 2 or the black connected to a ground source like a shock tower bolt. You'll probably get around the same reading becuase your car is fluctuating around 50% anyway.

I don't think that is correct Yal... since he is getting the correct KOEO reading (85%) with that test configuration... that would be the way to run the test.

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-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

Oh ok. Ignore me
But isn't that weird. I though pin 3 was the pin to read?

Christopher, have you done the 'key on engine off' duty cycle tests?

crhenkel, what is the build date of your car?
CD says 4/86 is the begining of fault recognition.

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html