Looking for Mr. Groundbar (W124) - PeachParts Mercedes-Benz Forum

Jeremy5848 · #1 08-02-2009, 08:37 PM

The ABS in my '87 300D Turbo (W124. OM603) is supposed to have two braided strap grounds and one brown wire ground, all at the hydraulic "pump" unit. My car has only one braided ground plus the brown wire ground and they go to ground point W14, which is essentially under the ABS pump, on the left inner fender.

The second braided ground is supposed to connect to ground point W11, which is supposed to be at the "left front of engine on intake manifold." W11 is also connected by a ground strap to W3 on the left inner fender. My car does not seem to have a ground point on the intake manifold nor can I find ground point W3 and the strap that is supposed to connect it to the IM.

All of this is shown in the factory ETM for this model, pages 149 (ABS), 163 (ground distribution), and picture 207-2 (W14). Because my car was abused in its earlier life, it may be missing stuff like these ground points. If anyone can take a picture of this W11 ground point on the intake manifold so I can see what I'm missing, the favor will be appreciated and possibly even returned.

Jeremy

compress ignite · #2 08-02-2009, 09:01 PM

FSM show picture of it on Page 232 Picture #1 in COMPONENTS section of ETM
BUT the picture is CLEARLY of a PETROL BURNER.

[On the '90 602 powered W124 I only see two electrical cables
1.A Teensy(when compared to the engine ground strap) Braided Strap from the
ABS motor to It's Mounting Point (Part of the Monocoque)[maybe 4 inches long]
2.The Plastic Conduit Sheathed main cable that runs over to the ABS control
Brain behind the Battery.(BUT, there could be any number of Ground Straps
concealed in the Plastic Conduit,that may or may not branch off before or after
reaching the ABS brain.)

In the EPC section 645 (brake lining wear indicator and antilock brake system)
NUMBER 18 (for the 124.133 chassis) they're only showing the small braided
ground strap MB #140 540 01 31 AND the control harness MB # 124 540 30 09.

Jeremy5848 · #3 08-02-2009, 09:17 PM

You and I must have different ETMs. Mine is a looseleaf (paper) manual, specifically made for diesel models 124.133 and 124.193 and it doesn't have a page 232.

compress ignite · #4 08-02-2009, 09:56 PM

I have to flail around on the net...

Is something Amiss with the ABS ?

Jeremy5848 · #5 08-02-2009, 10:32 PM

The ABS acted up when I first had the car . . . it kept doing the "when first turned on" test. A mechanic put his tester on the system and said that I had a bad wheel sensor (and maybe more). I replaced both front wheel sensors with junkyard units and that problem went away. I also have a spare pump and a spare brain but haven't tried them yet since the ABS seems to be OK. I so rarely use it that I don't have a good feel for what it should be doing or not. It does seem to work properly but my experience is limited. Ages ago, someone mentioned the importance of the ground leads so I compared the ETM diagram to my car and came up short a lead, I thought. Maybe there's nothing actually missing.

Bio300TDTdriver · #6 08-02-2009, 11:26 PM

Quote:

Originally Posted by Jeremy5848

The ABS in my '87 300D Turbo (W124. OM603) is supposed to have two braided strap grounds and one brown wire ground, all at the hydraulic "pump" unit. My car has only one braided ground plus the brown wire ground and they go to ground point W14, which is essentially under the ABS pump, on the left inner fender.

The second braided ground is supposed to connect to ground point W11, which is supposed to be at the "left front of engine on intake manifold." W11 is also connected by a ground strap to W3 on the left inner fender. My car does not seem to have a ground point on the intake manifold nor can I find ground point W3 and the strap that is supposed to connect it to the IM.

All of this is shown in the factory ETM for this model, pages 149 (ABS), 163 (ground distribution), and picture 207-2 (W14). Because my car was abused in its earlier life, it may be missing stuff like these ground points. If anyone can take a picture of this W11 ground point on the intake manifold so I can see what I'm missing, the favor will be appreciated and possibly even returned.

Jeremy

Why isn't the braided line that is connected to W11 numbered like 3 and 4 are in the schematic? I just looked at my car and don't see any grounds on the IM.

I did find some injector lines that were not in the plastic clip anymore. Now I'm going out to snap that back on, I hope.

Jeremy5848 · #7 08-02-2009, 11:30 PM

According to the key for the schematics, the little circles where the braided lines go into the pump are screw terminals. The others are numbered because they are part of a plug that plugs into the pump (under the removable cover).

Bio300TDTdriver · #8 08-03-2009, 12:14 AM

Well I have 3 and 4, but I don't see any other ground. When you say IM do you mean intake manifold? If so, wouldn't that require a rather long ground strap?

Now I have a question. Do injection line 4,5 and 6 have a plastic clip on them just before they separate?

Jeremy5848 · #9 08-03-2009, 01:01 AM

Quote:

Originally Posted by Bio300TDTdriver

Well I have 3 and 4, but I don't see any other ground. When you say IM do you mean intake manifold? If so, wouldn't that require a rather long ground strap?

Yes it would. One of the reasons I question it. Yes, IM = Intake manifold.

Quote:

Originally Posted by Bio300TDTdriver

Now I have a question. Do injection line 4,5 and 6 have a plastic clip on them just before they separate?

Yes they do. The attached pictures were taken while the manifold was off for a thorough cleaning. The red arrows show all the clips. The two metal brackets attach to the underside of the manifold with 6mm bolts (10mm wrench). The clip that holds all three lines is in between the metal brackets and over the ALDA in the first picture. Caveat: things tended to get moved around in the process of removing the manifold so the clips are probably not in their final positions in the pictures. It's almost impossible to get good pictures with the manifold in place.

I would add that most of my clips were missing when I got the car so most of mine and most of the steel bracketry is new.

Jeremy

Bio300TDTdriver · #10 08-03-2009, 01:06 AM

Quote:

Originally Posted by Jeremy5848

Yes it would. One of the reasons I question it. Yes, IM = Intake manifold.

Yes they do. The attached pictures were taken while the manifold was off for a thorough cleaning. The red arrows show all the clips. The two metal brackets attach to the underside of the manifold with 6mm bolts (10mm wrench). The clip that holds all three lines is in between the metal brackets and over the ALDA in the first picture. Caveat: things tended to get moved around in the process of removing the manifold so the clips are probably not in their final positions in the pictures. It's almost impossible to get good pictures with the manifold in place.

Jeremy

That's exactly where mine was except 1 line was snapped into the slot and the other 2 were in the clip but against each other. I gave up trying to get it back on after half an hour. I just LOVE the IM on the bleeping OM603. Of course the ALDA is right in the way too. I don't think it's worth pulling the IM to get that clip on. Looks like I'll be sticking some EPDM in between the lines tomorrow.

I don't think that ground strap exists. I think that one thick ground strap is doing a good job.

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