420 SE ('89) won't start (again)

Hi !
since march, 13th my MB wouldn't run: 2 seconds after starting it, it dropped dead! fuel pump relay and ignition unit have been replaced and it ran just fine untill today: after turning key, engine runs for 2 seconds and then stops! fuel pump is buzzing so what could be the problem..??

thanks very much.

Rémy K.

1)After you try to start it - lift the hood - do you smell raw gas??
2) Are you sure you have spark to the spark plugs??
Please advise

[dpetryk]

Try to determine if the problem is ignition related. Check for spark while cranking the engine. The problem is either fuel related or ignition related.

If you are not getting spark, there are a lot of areas to check next.

Thanks, I'll look into both!

Hi guys,

I think (hope) I've found the problem: the switch for the two-tone horn was not working and after replacing it, the fuel pump turned out to be connected to this switch (by the previous owner?), like a sort of contact breaker for theft prevention or so...
I suppose the old switch caused my starting problem (?).