Join Date: Apr 2012
Location: SF Bay Area California
Vehicle: 2006 SLK 280 Black
Other Toys: None
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Die Gelbe Gefahr status and chit-chat
Been busy and not on here too much, but on the way into the office this morning I passed not one but two other yellow R170s! One was a Sport model with the additional trim, don't know whether it was a 230 or 320. The other was a 230 like mine, I think the next year on (2001 or 2002, mine's an '00) because the door handles were yellow, not black. It was funny.
So my German "yellow peril" is continuing to provide great amusement and transportation. I've put about 7500 miles on it since I got it in April, it's at 130,000 or so right now. Just been through a little rough patch I thought I'd share.
Watching my fuel economy, I'd been noticing it drop over the past couple of months. A little bit here, a little there ... I do a lot of in-town driving so I'm accustomed to seeing a good deal of variability, but when the aggregate averages point down over several tanks I know something's up. About five weeks ago, it started to miss when idling, and it was about time anyway, so I brought it in for fluids and overall service/maintenance. I mentioned the rough running as well.
The codes showed issues with the coils, and who knows when the plugs were last changed, so I had all the plugs changed and new coils and plug ends fitted. That plus the other service work restored smooth running but it still seemed a little spastic at idle. "I'll just run it until something fails, that way I know what to fix..." Along the way, the K70 power distribution box decided to belly up so that was replaced too. Hey, it's an older car having a little mid-life crisis ... ;-)
Four days ago, the misfiring at idle hit again. Then the check engine light came up . Hmm. The codes said cam actuator and some other stuff when I brought it to my mechanic. We put it on the diagnostics and saw misfiring on cylinder 1. Swapped the wires around so that coil and wires for 1-4 were replaced by 2-3 ... still missing, still a good bit on #1. Hmm hmm. The cam actuator was new in April, could it have failed?
He pulled it off the engine and I started the engine up. Still spastic at idle. Now that's curious. Reached inside the cam and found the actuation slug was stuck. Jiggle jiggle and it popped free .. idle immediately smoothed out. Ah hah!
The actuator was new, but some crud had gotten into the slug that it actuates and the slug had gotten stuck at the position which allows the cam to retard for high speed running. It's supposed to go back to the resting advanced state at idle and wasn't. The mechanic cleaned it out and polished the slug smooth, reinstalled the cam actuator and hooked everything back up. Voila! This also explains the "good mileage on the freeway, bad mileage in town" performance I was seeing as with the cam retarded you're throwing away a lot of your fuel.
Fun fun fun ... Die Gelbe Gefahr is running beautifully again and I like it more and more. :-)