Anyone have a 380SL (107) Idle control unit I can test with? - PeachParts Mercedes-Benz Forum

RickM · #1 08-28-2007, 02:18 PM

Here's the deal....I have the common racing idle after warmup. After a while it goes back down again...then up.

A while ago I tested just about every suggestion I found on the board. I proceeded to remove my control unit and resoldered any joints I could.

Still have the problem. I purchased a used unit off Ebay and the problem was worse. It actually started with a very high idle and stayed there....just wouldn't kick down. I suspect the piece was not tested and I couldn't return.

So, does anyone have a known working Idle control unit I can borrow to test? If the price is fair I'll purchase if possible. If I can't purchase at least I'll know the true cause of my idle dilemma.

The Mercedes# on the part is 002 545 33 32 and looks like the pic below.

Thanks in advance.

sublettd · #2 08-28-2007, 07:45 PM

Rick,

I have one I believe to be good and could part with. PM me if interested.

Damian · #3 08-30-2007, 04:34 AM

Make sure you solder all the small red/green and sometimes orange, rectangluar plastic packaged capacitors they may not look like they have dry joints but it's very common.

Also try cleaning out your ICV valve with carby cleaner soak it for a while give it a few taps agains something to loosen up the build up inside then blow it out and try it again.

Regards

Damian

RickM · #4 08-30-2007, 10:24 AM

Thanks for the tips. I took these steps previously with no change.

I wonder if anyone has attempted a control unit rebuild. I'd imagine leaking capacitors are likely suspects.

Damian · #5 09-04-2007, 04:43 AM

You may want to try checking to o/p drive transistor? (Cheap easy to get)

There are only a couple of electrolytic caps on board by memory and they are usually ok, infact they are probebly better than some of the new smaller versions event the 105 deg ones from the likes of rubicon etc. They are cheap enough I would just swap them, f you don't have an ESR meter.

As I said I have hane alot of bad experience with the dirty leads on the poly and plastic tantulum type caps, some of these are aranged in a charge pump type cct that stores a voltage to compare against as a reference and some would be used to change the pulse width of op drive. So they are quite crytical.

There are only a few IC's on the board and they are easy to get and have the type numbers printed on the top (most manufacturers remove them), so you could swap them for only a couple of dollars and save yourself some time. Unlike me who traced most of the circuit out just to torcher myself ha ha.

Good luck

Damian