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Idle issues after major service

Started by 200 hp, 09 April 2011, 03:17 AM

200 hp

The car is a euro '74 D-jet 350SE.

The timing chain, guides, tensioner and thermostat were changed last week. Tappets were also adjusted as they were too tight. This job was done at a local mercedes specialist shop that I trust.

Since then the car has been idling too low and sounds as though its misfiring under initial acceleration. I adjusted the hot idle screw to make it at least driveable for work. Once fully warmed up it would idle way too low and eventually cut out when say, maneuvering into a parking space or in 'D' at a red light for too long. It then takes a while to restart. Don't know if the engine isn't getting enough air or fuel, or maybe the ignition is faulty.

Took it back to the shop and they adjusted the mixture and hot idle screw. They say the ignition is fine.
A day later the problem returned, there being no improvement at all.

Before I waste my time going back to the shop, do you guys know what the problem could be?

I should also note the car doesn't warm up properly. After initial start up the engine would rev normally as if it's hot, then after a minute or two finally start revving up to warm up. The temperature gauge is also showing higher readings when warmed up than before the service too. Reaching the second to last line of 100'C before red area of 120'C even though it's still chilly out. It used to always read between 80'C and 100'C.

WGB

?Lean Mixture or advanced spark will cause poor running and tendency to run hot - hope they got the timing chain right.

Bill

TJ 450

#2
I concur with Bill, it will be one or the other... First thing to check would be ignition and valve timing, as this is obviously directly related to the work just completed.

I also assume that all the points would need to be checked as well. Perhaps someone at the shop was lazy.

Also, it sounds like they failed with the cooling system as well, temp seems too hot. Maybe there is still an air pocket in the system?

I would tend to be rather cynical over these sorts of issues though, but that's just myself.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

200 hp

I hope they didn't make mistakes with the mixture or ignition timing, I trust this shop and have been there many times before.

I forgot to mention the last time I brought it in was because they didn't fasten the distributor cap down properly. It came loose completely and I'm amazed I was able to drive for a few days with it like that! The boss checked to make sure there's no moisture inside and reattached the cap.

Could this screw up have ruined the ignition timing?