Help, my car isn't starting
 

Over the last week I have been taking the water pump off and and other bits around it.(eg, radiator, fan, belt tensioner, belt ect.) I also gave the engine bay a good clean. Today I got everything back on and started it. It had a very rough idle and was rough up to about 2500rpm and then smooth out but still wasnt perfect. The engine started to cough and got more rough. The engine started to die so I tried to rev it but the engine died. When the engine died a big cloud of fuel vapour came out of the air intake. I tried to start it but no good. It fired a couple of times but never started.
The car hasn't been driven for about 3-4 weeks and the fuel tank is a bit less than 1/4 full. Can someone please help as I am really looking forward to driven her again.
PS thanks for all of the help you have supplied on taking the water pump out.

1988 300E (Euro) A/C Auto 280,000kms

Hi!

Have you tried some fuel system cleaner? My mechanic swears by Techron Concentrate or something like that. I even used it for my diesel...

I would start by emptying the fuel tank and starting with fresh gas.

Moisture in the distributor cap and/ or crossed plug wires will cause that to happen.

Well i got it started today. The way i did it was that i jumped started it. As soon as the computer got more voltage it started. The battery is a bit old so i am going to replace it.