Ignition timing

hello guys, I have a 1972 MB 300sel 4.5 with d-jetronic. Two years ago I bought used trigger points tool from Dr-DJet and I have adjusted the trigger as best I can, when I start up the car it runs with very high rpm 1500 and more. The only way to lower the rpm are by turning the distributor to 5 deg atdc, but then there are no throttle response at all. do you have any ideas of what my problem could be?

Hi Svein,

too high rpm does not come from ignition or fuel injection. It comes from air. So you have to verify AAV and other possible air/vacuum leakages. Press and close hose from AAV to manifold on wamr engine. If that changes rpm, it is AAV causing it. If not you have other vacuum leakages.

I have tried to block that valve on warm engine but the high idle won’t came down. I’ve also sprayed starting fluid all around the inlet manifold and hoses but there aren’t any major leaks

Hi Svein,

and idle-run screw will also not bring it down?

Just a little,

Then you have a vacuum leakage on your manifold for sure. That you have to find. Can be the rubber rings under manifold bridge, hose to MAP sensor, brake servo hose etc.