E-Class (W124) 1984-1995: E 260, E 300, E 320, E 420, E 500 (Includes CE, T, TD models)

Idle Problem

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Old Nov 17, 2010 | 08:38 PM
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1988 300TE
Idle Problem

I have a strange high idle problem on a '88 300TE..

It only happens when the car is warm and being driven for a while. Then the car idles about 1100-1300. No fun to hold back with the brake. It sat in the driveway tonight for about 20 minutes idling perfect. I has to be driven to really get it to act up.

Recently I replaced all the injectors, Inj seals, and holders. I replace the ICV hoses. New plugs, wires, cap rotor. Replaced a lot of cracked vacuum elbows. Replaced the "underside" rubber on the mixture control unit. Replaced the fan switch on top of the head, etc. Even cleaned out the throttle body.

The car starts well, better than it has for a while. Idles immediately at 900 when dead cold, then settles down to about 600-700. It sat for 20 minutes in the driveway at operating temp with this idle tonight. I used some mapp gas to try and find vacuum leaks and didn't find any. Listened with a stethoscope and didn't hear any. I looked for quite a while with the mapp gas.

When I had the mixture unit off I had the sensor plate out and wonder about it. So I shot some PIX with the car running. I guess it's centered, it "looks" ok to me.

I checked the rear temp sensor at temp and got 457 ohms. Does that seem right? It didn't change anything whether it was plugged in or not while hot.

I lubricated the throttle linkage and shot pix of it as well.

If I unplug, the ICV electrical connector, the car stops immediately, is that normal?

The only other issue is that somewhere along the line of recent "maintenance" I had the wheel off and the SRS light is on solid, won't go off. The bag is plugged in. I checked the Fuses on the OVP relay and they are good. Is there a way to check the relay itself?

So I'm kinda stuck here, any ideas where else to look?

Here's some pix:

http://www.turbonet.biz/misc/MB_Idle/AAA_2249.JPG

http://www.turbonet.biz/misc/MB_Idle/AAA_2250.JPG

http://www.turbonet.biz/misc/MB_Idle/AAA_2251.JPG

http://www.turbonet.biz/misc/MB_Idle/AAA_2252.JPG

http://www.turbonet.biz/misc/MB_Idle/AAA_2253.JPG

http://www.turbonet.biz/misc/MB_Idle/AAA_2254.JPG
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