here are the symptoms...

when the car is started in the cold, it runs and idles just fine, until it starts to warm up... then...

.. when its at say.. low medium to medium high it has surging at idle, never under throttle. with no throttle at a stop, its slight in neural, a little more pronounced in drive, and moreso in reverse. if i let off the brake (and dont touch the gas) its starts a resonance that goes absolutely herky jerky in reverse, and drive isnt a whole lot better. throw it in neutral and it mostly settles, but sometimes not. hit the gas, and its gone.

now, if ive been driving for while or i let the car warm up for 20 minutes, its mostly behaved. then when i shut it down without it really cooling off, its REALLY cranky. idle bunces everywhere at a stop, in gear or not. its just horrible.

accelerator linkage?
idle speed adjustment?
idle speed control actuator?

other?


im currently waiting on parts to make a code scanner, but if anyone has run into this before and wants to post up...

... it would be much appreciated!!!!

Thanks
zimm

Throttle actuator or wiring, pretty well-known problem. Probably the actuator, but inspect the wiring. Sometimes the wiring IN the actuator, Some I guess have taken to repairing the wiring if it's just in the actuator. If it's the engine harness you'll probably want to just replace it, it gets pretty intensive to try to repair the whole harness. The harness lays in that cable tray on the drivers side of the valve cover, pretty easy to look at the wires running to the various sensors, look for cracked insulation and bare wire.
In your case though it realy sounds like the actuator. The idle hunts rather rapidly like a quick rumrumrum sound

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My 1991 300E (103 engine) had an idle suge for approx. the last 4-6 weeks. It was VERY intermittent; surged approx. 500 RPMs in park, drive, and reverse and got dangerous in the respect that he car surged forward at red lights.

I checked for vacuum leaks (none); replaced the coolant temperature sensor (no difference); cleaned the throttle body and all other components with carb cleaner (improved for a day); removed and cleaned the idle control valve and replaced a cracked hose leading to it (no difference)

Yesterday, I found a 1990 190E at a pick and pull with an intact idle control valve. I replaced it and have had no problems since. Check this site, your local pick and pull, or eBay for an Idle control valve

Would the effect of high idle when in neutral be possible from a faulty idle ctrl valve on an m119? I'm having not so much a surge, but a general high idle anytime, cold or warm, while in neutral.

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former: 83 300D, 97 C230, 93 400E

current: 08 C300 Luxury , 92 500SL

Will, on the 119 engine that should all be handled by the actuator, not an idle control valve.

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That's what I thought, however Fastlane does show an idle ctrl valve for my motor.

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former: 83 300D, 97 C230, 93 400E

current: 08 C300 Luxury , 92 500SL

i guess since my motor is a euro spec G not sold in the US fastlane doesnt actually have .996 listed. im using a similar e320 for reference.

i dont see an idle control valve. im waiting on my parts for a reader to show, not much more specualting i can do before then, but i strongly belive its the actuator. ive had this issue for over a year, and last month a mechanic working on my car accidentally cut 6 wires in the harness. (long story, i'll do the work myself from now on). when he did so the idle was gone completely. i had to booger rig the throttle to make it drivable. i noticed thos couple day though, that the surging was gone. when i discovered the wires and repaired it, the idle was back, but so was the surging. looking at the lines, i lost a temp sensor and the actuator.

so, i bet its the actuator. im looking into options that dont include a 1200 dollar part on a weekend wheeler.

i notice some sites that rebuild them for 3-400 bucks, or i could do it myself. i think ill split the harness plug and give it a shot.

if anyone has an actuator that degraded cheap, i'll buy it off of you for a practice run. part number 000 141 57 25 i think.

I read that internal wires rot inside actuator,and it can be repaired by ones self.

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1999 w140, quit voting to old, and to old to fight, a god damned veteran