1988 Mercedes Benz 260e wont start

You need to check for injector pulse if you know youre getting fuel to them. Unplug one and plug in a noid light and watch for blinks whenthe engine is turned over. Noid lights are inexpensive and may even be rentable at parts stores. If you have lights your injector is faulty. If you don't, then id check the crankshaft sensor for signal. If you aren't comfortable doing this, at least check and follow wires from the injectors out to see if anythings broken or unplugged