1990 300E won't start
 

I have a 1990 300E (175,000) that will not start.
When I turn on the key, I can hear the fuel pump for 2 seconds (normal). but when I crank it, there seems to be no gas. Thinking it may be a bad MAS control unit, I bought a different (used) one. But it has the same symptom, You turn the key and you can hear the fuel pump, then crank it but there is no gas.
If I turn the key to the on position a few times, then try to start it, it will cough (like it wants to start), but still nothing.
HELP!
Any suggestions?

Thanks in advance.

you need to find out if you have no spark or no fuel.the td signal from the ignition unit is used to hold in the fuel pump relay in the mas.might be an old tired sensor on the fly wheel which feeds info to the ignition unit.this might also explain the occasional cough.

...and it could be as simple as a plugged fuel filter.