Date registered: Oct 2009
Vehicle: 2007 GL450; 2000 SL500 (AMG Sport); 1999 CL500;
Location: West Michigan, USA
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While you are running your analysis, are you absolutely sure you have the exact correct Bosch points? Back then, when they had the 'module' you mention, the points were a special chrome plated unit. A std set of points, that will fit and look the same, will not give the same performance as the special chrome plated points.
Provided you have the correct coil (blue I believe) installed and it has not been replaced (you mentioned a different coil), then the chrome points were for a purpose. The ignition module had a very low current draw, which did not burn off containment from the points. The chrome points were intended to maintain very good, read low, impedance and therefore good current through the points, which in turn triggered the module. It was a nice design, but the points were a weak point, if the incorrect points were installed.
Also, make very sure that the distributor is turning very freely and its shell bearings are fully lubricated. The bottom bearings of the distributor is oiled via a small cup, that is revealed by rotating a cup cover to uncover the oiling gallery. I would recommend pulling the distributor (please ensure that the exact re-insertion to align its gears occurs) and verifying that it is fully lubed and rotates easily.
If the distributor starts to hang up, it will throw off odd symptoms, including eventually tearing up the cam drive chains and sprockets...did I say ouch!?
P.s., these remarks apply to any MB of that vintage, 6 or v8.
That's my input. The points and check out the distributor.