Tom Hundt's Infomonger Pages
 Mercedes-Benz Tinkering - High Idle Hell 

I just went through High Idle Hell with my '83 380SL. It was idling at 1500, most of the time, and stalled on occasion. Here are some notes.

This is a common problem with these cars. Examples: example example example . (You may notice a common thread here: The computer.)


For '83, the components to the electronic idle speed regulation are:

Other years include other temperature switches and stuff. RTFM. (The factory cdrom describes this stuff under 07.3-112 "Testing electronic idle speed control".)

Normal operation

Abnormal Operation

Here's a typical pattern:

Quick tests

Other Things to Check

If It's the Controller (Computer)

If everything else seems okay, it's probably the controller. From my research, this is it in most of the cases.

If you want to let someone else do the soldering, here are some places to buy remanufactured ones:

Once You've Gotten It Working Just Sitting In Park

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