When facing a no-start situation after doing some work, I always ask: What was the last thing I did? You did some work on the ignition system. Maybe you didn't do the work correctly. The engine will start without the accessory drive belt. It will NOT start without a properly configured and functioning ignition system. Test for spark by disconnecting a plug wire and connecting it to and old plug that is grounded.

Not with my Merc, but I recall doing some ignition work on my Cosworth Vega and it would not start. I forgot to install the rotor! Another time I had forgotten to connect the coil wire. I think I made the same error on my Corvette 30 years ago. Another time the CV would not start because I had forgotten to connect the speed sensor connector. No speed sensor signal to the ECU and the EFI won't open the injectors - no start.

It's often something very simple and often a result of our own errors.

Since most of us probably don't have a proper pressure gage and adaptors to check fuel pressure, the "poor man's way" is to just sniff the exhaust while someone cranks. If it's getting fuel, you'll smell it!

Duke