1984 380 SL convertible/roadster

[Poltergeist]

So I just got a 1984 380 SL convertible/roadster that had been siting for a very long time, so long in fact that the fuel went to turpentine. I drained the tank, replaced all the spark plugs, added 6 gallons of high octane to help clean the fuel system, replaced the fuel pump and the two filters under the car, also cleaned out the frequency valve (which is leaking). After all of that, the car will run and nicely, but it will not idol on its own...

Any ideas on what to do next???

Thanks
Jg.

[INSIDIOUS]

Originally Posted by Poltergeist

So I just got a 1984 380 SL convertible/roadster that had been siting for a very long time, so long in fact that the fuel went to turpentine. I drained the tank, replaced all the spark plugs, added 6 gallons of high octane to help clean the fuel system, replaced the fuel pump and the two filters under the car, also cleaned out the frequency valve (which is leaking). After all of that, the car will run and nicely, but it will not idol on its own...

Any ideas on what to do next???

Thanks
Jg.

Nice ID MB advises to NOT use any gas additives. I would recommend a healthy dose of Sea Foam in the gas. That should remove any doubt about fuel. I'd also do the wires and cap. Fix that leak. Euro or NA? The idle air controller and the associated card have much to do with idle stability. Simple to check if the valve responds to 12V. Just touch it briefly, notice max response. It operates by variable voltage. Those cards fail and are unobtainium. Rebuilds can be had. First test would be to unplug the black box and examine terminals for corrosion. Plug it back in with generous rubbing of the contacts to assure good connection. You might also unplug the main brain box and inspect and reattach. If your idle is not restored it could be something else or possibly the card itself. You can open the box holding the card and examine for solder issues. Or even fried components. What happens next depends on your PCB board skillz. Air fuel for idle can also be tweaked via the plenum adjustment. That should never get out of adjustment by itself.