duty cycle and TD signal question

[benfield4]

Hello

Still learning about this fuel system so please bear with me!

I have an 89 300SE, M103.981 with California KE Controller and diagnostics port by battery.

Getting ready for Washington State Emissions test and wanted to check the health of this thing. Only issue the car exhibits is a low idle when fully warm with an economy gauge reading over the "O" or just off the red. On a warm start after its been sitting for a while it idles pretty rough to the point where it almost stalls. Have searched for vacuum leaks and have replaced a lot of rubber hoses (including the IAC hoses) but not found the magic bullet yet.

As for the duty cycle here is what I have done.

1. Key On Engine Off (KOEO)

2. Sears DVOM on X11 black on 2 red on 3

3. Duty cycle reads 85%, tells me its a California car.

4. Using the Aurthur Dalton code reader hooked up to the diagnostic port by the battery hold the button for 3 seconds wait and get a single flash.

5. Wait for a few more seconds and then hold down the button for another 3 seconds.

6. Now the DVOM shows a duty cycle of 70%. Is this telling me I have a problem with the TD signal and need to run the TD test per the fault chart? This is the signal from the crankshaft position sensor correct?

The Tach works and the the only issue noted above is the low idle.

When I start the car and it is warm enough it enters closed loop and I can set the Duty Cycle.

I started testing the TD signal per the manual. It had me do the following:

1. Test Pin 25 on the KE control connector with the engine running. Got 8 volts DC.
2. Test Resistance of connection between KE connector 25 and Fuel Pump Relay position 10. Got 0 ohms and it has continuity. Ok here.
3. Next test is to "Test Line Between Jack 10 (relay Fuel Pump) and diagnosis socket/Line connector TD for continuity". Question - I am not sure where this socket is. Is it one of the Pins on the X11? The one that goes to the coil?


I also tested the Crankshaft position sensor that plugs into the EZL. I tested it for resistance on Terminals 7 (inner) and 31d (outer) of the sensor. With the DVOM on auto ranging I got 930 K Ohms. Rated Value is 680-1200 Ohms. Setting the DVOM to Ohms I get 0. The K ohms reading is in spec but I get nothing on Ohms so do I have a bad CPS?


Thanks for any input!




[IMG]file:///C:/DOCUME%7E1/brubrigh/LOCALS%7E1/Temp/moz-screenshot.png[/IMG][IMG]file:///C:/DOCUME%7E1/brubrigh/LOCALS%7E1/Temp/moz-screenshot-1.png[/IMG]