The Joy Of 240's, with issues...

[CosmicBike]

I am sick of decorating! Sanding doors and making dressing tables got tiresome, so a bit of a fiddle.
A workmate of mine is also a car nut (Stag and Astra GTE), and on a shift last week we got chatting about stuff and he found an interesting bit about Idle Air Control Valves on a Mercedes forum. Never knew they were proportional, and varied based on input voltage, though it does make sense. Whilst I was confident mine was OK, I did a little test with a battery from one of my lads RC cars, circa 9-10v. ICV positioned differently to on 12v. Whilst it was off the car I checked both hoses to and from the unit, all OK. Also check the resistance of the ICV, 8 Ohms, exactly as it should be. Started car with valve removed, 2000 rpm idle!! Tested voltage at connector, steady 12v regardless of throttle position, so figured ECU needs to see the 'load' of the ICV. Refitted, and 'back-probed' the connector. Engine started and I got 8 Volts, steadily decreasing as the engine warmed up. According to the MB data, a warm engine idle seems to be about 4 Volts. Mine got down to 5.9 Volts just sitting on the drive, temp gauge just off the bottom, so I'd say it's fine.

Changed air filter, and noted the hot/cold airbox flap was on the hot intake. Removed airbox (along with more knuckle skin, again..). Interesting little thermostatic plunger actuator on the flap. Took A LOT of heat to move the flap, holding the actuator in the flame of a lighter until too hot to touch. Now I figured it would move at about 20 Degrees? Anyway, I've removed the flap and actuator which rather handily just clips into the airbox. Also blocked off the hot intake. I read somewhere on here I think that these can stick on the hot inlet and damage the MAF, so I'll leave it as is I guess.

Also a quick MAF test, disconnected whilst engine running. Engine stopped instantly.

So no nearer the fix, but learning the car. And it beats decorating