I checked the fuses first thing lol. They were all good.Check the Fuel Pump Relay in the Trunk (Red Arrow in pic below) & all fuses & the Fuel Pressure Regulator that it is not clogged up (Fuel Filter recently changed ?) .
The Reason the car starts briefly is because the fumes of petrol that reach the engine make it briefly start ,obviously either a relay malfunction or the petrol pump (pump's as some have two) ,start with the relay 1st as it is inexpensive , even one that is in your 2nd car like a Ford etc with the same design pins will work ,it doesn't have to be MB 140 ( done that been there) then jump to the more expensive parts if the relay is ok ,i got two dumped here for spares come get em (lol) . Have you checked on that Fuse in the Module Box in the engine bay yet (as mentioned in other Thread ) ?. :thumbsup:
Some Pictures you might be interested in .:wink
I've driven a perfect running one and used that as a basis.Since you have the 722.3 transmission, it normally starts off in 2nd gear. You have to put the gear lever in position "B" to start I first. There is also a model somewhere in the other forms to force it to start in first. Makes a significant difference.
Also, the M120 engine really comes on in the high rpm range. Acts almost like a supercharger is kicking in.