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]

Did some more reading and looking at a wiring diagram. TD signal is on the X11 socket on Pin 1, makes sense that it is since that is the RPM signal pin. It tested fine there as well as on the TD pin on the EZL so I have continuity in the wiring harness from the EZL - X11 - Fuel pump relay - KE Controller. So if I have an issue its an intermittent one with the Crankshaft position sensor. Its a tad expensive so I am hesitant to replace it when it may do nothing for me as a few other parts I have purchased.

I was able to complete all of the tests and set the duty cycle Via the Landiss article so that is positive. I will try for an emissions test now and anything that has to be done to it will go toward the $150 exemption limit.

My M103 manual is a good book but its easy to get confused reading it. More and more experience working on the car will get me over the hump on this.

Your vacuum gauge should be pegged full to the right at idle, warm or cold. If not, you have leaks in your intake. I wasn't sure based on your description. The vacuum gauge is a real valuable diagnosing tool that they removed on the later W124 cars.

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http://i193.photobucket.com/albums/z...-RESIZED-1.jpg
1991 300E - 212K and rising fast...

Before replacing the CKP sensor check the fault codes with the engine running. Some modules recognise a TD fault when they are scanned with the engine off.

__________________

90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff

Well I took it for the test today and it passed emissions! So that is good!

cruise results at 25mph
HC(PPM) Limit 150, car 49 pass
CO% Limit 1, car 0.15 pass
CO+CO2% limit 6, car 15.35 Says N/A for the result
O2% limit N/A, car 0.11, Says N/A for the result

Idle
HC(PPM) Limit 220, car 39 pass
CO% Limit 1.2, car 0.01 pass
CO+CO2% limit 6, car 14.01 Says N/A for the result
O2% limit N/A, car 1.92, Says N/A for the result

I had set the duty cycle to 50% over the last weekend and took it for a 15 mile freeway cruise before the test. Did not wait in line and got right into the test.

JohnM, Think you mean pegged full left at idle. But I agree with you its not right. I need to run that vacuum test where you disconnect everything and monitor the O2 signal while spraying all the vacuum connections at idle.

duxthe1, I had wondered about whether or not it was just telling me that the car was not running. I will try the whole thing with the engine running and see what I get.