I ran into that with the 99E320, ordered one and it didn’t fit so dug into it and found the serial number aspect. Got the right one and all was good
--FT Sent from iFōn > On Jan 28, 2024, at 3:26 PM, dan penoff.com via Mercedes > <mercedes@okiebenz.com> wrote: > > Swapped out the offending part this afternoon, which took all of maybe 10 > minutes, if that. I’ve done plenty of these in the past, but this one was the > worst due to one of the connector release tabs being right up against the > back of the block. > > Beware if you are a W210 owner: There are at least two different CPS’ used by > Mercedes with the M112/W210, and pre-facelift, with a serial number break > based on engine number, have a different CPS than later models. That said, > they look identical on the outside, but the inside of the connector housing > on the CPS is different, that is, they are “keyed” differently inside: > > > [CPS Early.jpg] > > > If you look closely, you’ll see three “keys” inside the connector hood. The > arrangement of these keys determines whether it is the “early” or “late” CPS. > The part number for the early CPS (the one shown here) is 003-153-96-28. I > believe the later part is a 003-153-28-28, but always verify with the EPC or > a trusted parts supplier before ordering using your VIN. The later part is > keyed similarly, but the keys are in a mirror image to the early part, that > is, their orientation is reversed. I’ve kept the later part on the shelf with > several M112-powered cars in the fleet, not realizing there were variants. > > I would be willing to bet that in a pinch either would work after you cut or > scraped the keys out of the connector hood or just cut it off completely (not > advised.) > > As for the post-mortem, this is what we found: > > The CPS installed in the car was an OE part but was not original. I say that > because someone took the trouble to schmear (and yes, that’s a technical term > as you’ll soon discover) anit-seize on the barrel of the CPS. I used the term > “schmear” because the amount of anti-seize they used was, to put it bluntly, > excessive. These are held and centered in the bore drilled into the bell > housing with three small ribs that are molded into the case of the part. The > barrel of the CPS never touches the bore. Worse, upon closer inspection, as > one would expect, the anti-seize, which as we all know is mostly grease with > aluminum powder mixed into it among other things, had leaked down the length > of the CPS, covering the end and no doubt dripping into the bell housing and > onto the flywheel. > > Being very familiar with similar devices used for monitoring speed on > industrial engines, I would point out that any foreign material on the end of > the CPS is a Bad Thing, Even Worse when it's something metallic, even > aluminum. Essentially, that mess on the end of the CPS “shorts” out the > magnetic circuit that the CPS uses to work, either disabling it or making the > signal marginal or intermittent. > > I suspect this was the issue with this failure. Interestingly, it never > occurred a second time. That and it failed late at night on a cold evening > after the car had been parked for several hours, so it certainly wasn’t heat > that caused the failure, which is what I have experienced with these failures > in the past. > > Finally, to give you an idea of how critical the signal this device provides > is, my son reports that it drives like a different vehicle. He said the > engine runs smoother, shifts are crisper and timely, where they had been > occasionally wonky, and in general, the car just runs better. While I’m sure > there’s some placebo effect here, I believe him in what he describes. I have > to believe all the crud on the end of the CPS was seriously degrading its > output. > > While I wouldn’t use my findings as a determination for the CPS to be > replaced regularly, it can’t hurt to pull it and inspect the end to make sure > it’s clean. That was an inspection item for an industrial engine when I > worked on them. Why? Because something as simple as a shaving from a flywheel > tooth when it meshes with the starter Bendix could short out a CPS - and that > metal core in the center of it *is* magnetic! > > And now to the front brakes on the 2003 E320... > > -D > > _______________________________________ > http://www.okiebenz.com > > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com > _______________________________________ http://www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
