W124 E420 several codes on several pins - Page 2 - PeachParts Mercedes-Benz Forum

Andras · #1 09-05-2011, 02:19 PM

I finally finished with my ETA rewiring. When I connect the ETA and turn the ignition on, it will not hum, only jerk the butterfly valve once. Is this normal? I am afraid to reinstall it, unless I know it works.

JimF · #2 09-05-2011, 03:14 PM

Congrats on completing the re-wiring . . . I'll bet it wasn't easy!

Now is the hard part . . if it doesn't work after you re-install it, what do you do next?

It's been my experience that when the ETA's input/output cable crumbles, failures occur in the ETA. So it needs to be tested to ensure that it's ok.

Andras · #3 09-05-2011, 03:32 PM

Thanks, Jim! It was very challenging and time-consuming. Sourcing Teflon wires and finding the right sheathing was difficult. Mapping the stripped wires between the connector and board was almost impossible. Cutting the connector was tough. My wife and I spent about two days desoldering, soldering, creating the harness, and testing. I am fortunate to have two heads and four hands.

I will reinstall then and hope for the best. Based on the Mercedes CD wiring diagram for the ETA (which seems to be messed up between the engines) the motor, actuator, 2 potentiometers, and two switches are fine. I tested with an ohm meter. Also watched and followed Victor's excellent video: http://www.restoreyourmercedes.com/Mercedes%20throttle%20body%20rewire.html

JimF · #4 09-06-2011, 03:57 AM

Quote:

Originally Posted by Andras

Also watched and followed Victor's excellent video: http://www.restoreyourmercedes.com/Mercedes%20throttle%20body%20rewire.html

That is a great video . . . very impressive, indeed! Have added the link to my ETA page so all can see another source for ETA repair. Price is excellent also!

Also added a Wire-Gauge Table showing the AWG sizes required along with the corresponding connector pins. Very handy table!.

A caveat via my story: when my ETA failed, certainly the wires were toast so it's amazing that it worked as long as it did. However, the butterfly "clutch" burned open and that was the "real" failure that caused the LH and other ETA going-bad anomalies. The wires, as bad as they were, were not the problem (at that time) b/c the ETA harness had never been disturbed. Also the reference pots were worn but still ok.

So the point is that you still need to inspect (and dis-assemble) the complete unit if you are a DIYer; the wires are certainly one large factor in the failure mode but they are not the only one that can cause a ETA failure.

Using Victor's "ETA-static-test" video should show if there are some gross failures, so, absolutely, it should be done.

Shops like Beckmann Industries have a real M119 test-jig that completely tests the ETA in a closed servo-loop. Bad parts are immediately spotted either BEFORE or AFTER re-wiring of the unit. That test jig is a wonderful thing . . .

emerydc8 · #5 09-06-2011, 04:34 AM

That was a very informative video, especially the bottom video where he shows how to test the ETA with an ohm meter. Thanks for posting the link.

Andras · #6 09-05-2011, 07:43 PM

I installed the ETA. The car starts and runs, but the idle will not go below 1,400 rpm. I connected all vacuum hoses and the brake vacuum pipe. I doubt there is a vacuum leak. If I mistakenly reversed the motor wires, could it cause this symptom?

JimF · #7 09-08-2011, 01:57 PM

Quote:

Originally Posted by Andras

The car starts and runs, but the idle will not go below 1,400 rpm. If I mistakenly reversed the motor wires, could it cause this symptom?

Referring the ETA schematic here Pin 4 is the [motor] M1's positive pin; Pin 11 is M1's negative pin. Reversing them would cause a problem. Same for the "clutch" . . but here I don't know what the normal control voltage/current polarity is since it's not marked. That can also be said for the ref pot, R2.

Doing a static ohmmeter bench-test does not show polarities; however, its great for locating "dead" parts such as the motor, clutch and ref pots.

Andras · #8 09-08-2011, 04:45 PM

Thanks, Jim. I believe I have the motor wired backwards and the car is in limp more from start. Since I didn't glue nor seal the connector, reversing will be easy.

Andras · #9 09-09-2011, 11:22 AM

Good news: I inadvertently had wired the motor on the ETA backwards, and now after correcting it, the car starts and runs without limp mode. I ran it for 30 minutes without stalling. It now buzzes as it should with the ignition on. I initially got the idea from this thread: Connector for ETA - and rewire

Victor of http://www.restoreyourmercedes.com/index.html was as kind as to confirm which pin goes to which terminal (left, right) inside the ETA. They are not marked.

Bad news: Once the car is warm, with A/C on, placing the transmission in drive or reverse makes the engine idle below 500 rpm, and almost stall. I have to quickly switch to neutral and press the gas pedal to save it. Also, there is a vibration around 1,700 rpm. It seems there is a missing cylinder.

I am planning to do the following:
Restrict air to the MAF sensor with hand on top, to see if system compensates by opening the throttle
Disconnect the MAF sensor (I just cleaned it), and run engine, to see if it runs better
Listen to each injector with a stethoscope, to verify they are all firing
Plug each vacuum port on intake, to ensure there is no vacuum leak
Erase and read the codes
Compression test, but I think I would have worse symptoms with a stretched or jumped timing chain

Should I test anything else?

JimF · #10 09-09-2011, 01:07 PM

Quote:

Originally Posted by Andras

Bad news: Once the car is warm, with A/C on, placing the transmission in drive or reverse makes the engine idle below 500 rpm, and almost stall. I have to quickly switch to neutral and press the gas pedal to save it. Also, there is a vibration around 1,700 rpm. It seems there is a missing cylinder.

There's an idle compensator which kicks in when A/C is on. Suppose to compensate for the compressor "drag" on the engine. Sounds like that's not working?? Don't know where it is.

Andras · #11 09-09-2011, 01:30 PM

Quote:

Originally Posted by JimF

There's an idle compensator which kicks in when A/C is on. Suppose to compensate for the compressor "drag" on the engine. Sounds like that's not working?? Don't know where it is.

The only place I imagine it can be, is part of the ETA function, meaning the the ECU instructing the ETA to open the throttle more. The same should be true for the engine running cold, shifting from park to drive, and for cruise control. I believe the ECU should control the butterfly valve in all those conditions.

JimF · #12 09-09-2011, 01:47 PM

I pretty sure that it's NOT part of the ETA . . . it's a special "diode" matrix (if I remember correctly) that compensates the idle . .

Need help from somebody that knows . . .

emerydc8 · #13 09-09-2011, 05:21 PM

For what it's worth, I had a similar problem years ago where the engine almost stalled when putting it in reverse. It turned out to be a bad neutral safety switch. But if it's only happening with the a/c on, it sounds like Jim's suggestion is correct.

Andras · #14 09-10-2011, 11:09 AM

I erased all codes on all pins. Restarted the engine. On pin 7 code 6 returned. Do I need to replace the neutral safety switch?

JimF · #15 09-10-2011, 12:35 PM

EA/CC/ISC module - "Code 6 - - - Starter lock-out/backup lamp switch (S16/3 -NSW) ".

As your read in Menu#24, my NSS went bad b/c it was "old" and "ohmic". It couldn't hurt to replace it.