86' 300e won't start
 

Car started after many months of sitting.

We started it and the belt broke:

Replaced tensioner and belt

Replaced plugs
Replaced distributer cap and rotor.

Changed oil and Filter

tried to start, now won't start.

How to I check the gas flow.
Any Ideas would be greatly appreciated.

C. Kimble
300E 1986
190E 2.6 1992

To measure fuel delivery one installs a pressure gauge and removes the fuel return line from the fuel pressure regulator. You then bypass the fuel pump relay verify fuel pressure at 5.3-5.5bar and catch the fuel coming out of the regulator. Should be something like 1 liter in 40 seconds. Both pressure and volume are critical, especially pressure.

This could be obvious, but did the belt break for a reason? Perhaps the stuff the belt turns is no longer turning, like the alternator or the water pump.
Does the motor turn over freely?

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