Idle started going to 1800 all the time, 1000 in drive. I checked all the fuses and vac connections. Can I narrow the problem down to the idle air valve, or the control module? I checked voltage at the air valve and its about .5V. Where is the control module located?

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1985 380SE Blue/Blue - 230,000 miles
2012 Subaru Forester 5-speed
2005 Toyota Sienna
2004 Chrysler Sebring convertible
1999 Toyota Tacoma

check the idle intake tubes for leaks. Air will leak into the idle system and cause the engine to idle too fast, and the idle control valve cannot close tight enough to compensate for that.

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Marty D.

2013 C300 4Matic
1984 BMW 733i
2013 Lincoln MKz

Very ironic that you mentioned that. I also have a 1985 380SE and I just got back from an errand. I did not notice it when driving in town, but when I pulled in the driveway, it was idling at about 650 rpms (in gear) and idling at about 900 rpms in park, whereas it was idling at 750 in park and about 500 at idle. I shifted into "R" to see if it stalled out like it had been doing after the engine was totally warmed and it did not stall, but it harshly banged into gear. Something is not right here.

Idle control module is very easy to get to. What you need to do is to resolder all the solder points on the board. After years' of vibration under the hood, it is a way to revitalize the module. Otherwise, it is very solidly built.

The above did the trick for me.

Well, I took my car out on an errand again after I replied and now my idle is back at about 550 when in drive and about 700 in park. Maybe it was my imagination, but still it does stall occasionally when placed in gear.

Joy! When I pulled off the module, I found the connector partially detached, possibly from when I cleaned out the firewall debris a few weeks ago. I pushed it back in and the idle dropped back to normal. If the problem comes back I'll know to check here for bad solder joints too.

As always, thanks to all who responded.

FYI, the idle module is also called the Leerlaufdrehdahlregelung (!)

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1985 380SE Blue/Blue - 230,000 miles
2012 Subaru Forester 5-speed
2005 Toyota Sienna
2004 Chrysler Sebring convertible
1999 Toyota Tacoma

Strange. Not too long ago, someone posted a photo and circled the "idle control module", but they showed it to be toward the front of the engine, behind the distributor and now I am hearing that it is by the firewall? Any photo of it in this area? Just wondering, because if my "stalling" when placed in gear continues, I may check it, unless I take it to the shop first.

As mentioned, earlier today, it was idling faster than normal, but I noticed that the temperature gauge had dropped to about 60*C after driving on the highway- which is about a half a mile from my house. It may have been where the engine had cooled. I think I have a glitch with my thermostat or something.

Good to hear yours is back in order. How about when you shift in gear when the engine is at full temperature? Do the RPMS go way down initially and it acts like it is going to stall?

Thanks

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2004 Toyota Sequoia Limited 4wd
1991 Lincoln Town Car Executive
1991 Cadillac Sedan DeVille
1988 Mercedes 300SEL
1972 Chevrolet Caprice Kingswood Estate 9-passenger wagon
1973 Pontiac Grand Ville
(Prior MB's: 1974 240D, 1985 380SE, 1984 190D, 1993 400SEL)

That picture was probably the idle air valve. It is controlled by the module. On our car, its a black box in the middle of the firewall towards the brake booster side. The connector presses onto the pins on the bottom of the box, and nothing really holds it on securely. Maybe a long zip tie would make sense.

Idle is 550-600 rpm in drive, 700 in neutral. No stalling.

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1985 380SE Blue/Blue - 230,000 miles
2012 Subaru Forester 5-speed
2005 Toyota Sienna
2004 Chrysler Sebring convertible
1999 Toyota Tacoma