cross posted with you Graham good reply

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61 Austin mini
67 Lotus 7
74 450sl
76 Cadillac 8.2l (501 ci)

some new cars

megasquirt conversion on:
djet 74 450sl http://www.mercdjetmegasquirt.britautorepair.com/
cis 76 450sl http://www.merccismegasquirt.britautorepair.com/

the best view is always from the point of no return

It looks like we're narrowing it down to an ignition problem as the car died at the dealer after running only one minute. They said the fuel pump was running and the coil tested fine.

Next is to check the switchgear, brain box and other items which I will pass along.

I do have the service manual which goes in depth in how to test the various componets. The dealer's going to see if they still have the Bosch tester for the ECU.

Will keep you posted!

I recently had a somewhat similar incidence where my car (’66 250SE Coupe) stalled a number of times – and no power at all eventually…. Long story short, I traced it to a bad (old, neglected) small “cable connector” which is located on a metal bracket mounted near the bottom of the oil pan/block and serves as a terminal block via 2-poles on my car. Poor thing was entirely encrusted with debris and had a corroded screw/nut… it was cracked and burnt due to age and wear & tear so it eventually gave out, and the location of this component is in such a poor area since it is susceptible to immediate road debris, grime, deposits, oil, etc.... Replacement part from MB is on its way… I’m not sure if your model has it or something similar (yours is likely updated since it’s newer) but it is worth investigating, particularly to rule it out. Check other electrical components as well, including but not limited to the VR.

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My Mercedes-Benz Homepage and W123 Owners Photo Gallery and W111/W112 Coupes & Convs Gallery
2005 Northeast GTG and 2005 Mid-Atlantic GTG and Summer '09 Central FL GTG on YouTube

Thank you all who replied both on and off list.

The problem, discovered by the dealer's shop foreman was a broken connection in the wiring beneath fuel pump relay in the engine compartment. It's great to have my car back home in the garage!

Sound good! Glad it's fixed...
As I stated above, I had a similar issue with mine which I promptly diagnosed & fixed. Since these classic cars are easily over 30 years old... it's normal to find a few dry-rotted, aged, or damaged electrical components especially under the chassis.

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My Mercedes-Benz Homepage and W123 Owners Photo Gallery and W111/W112 Coupes & Convs Gallery
2005 Northeast GTG and 2005 Mid-Atlantic GTG and Summer '09 Central FL GTG on YouTube