w126 fuel pump relay

[dave500sel]

Am i correct in believing that although the pumps prime when the ignition is turned on the relay could still be faulty and cause lack of fuel supply when cranking the engine over or am i mistaken ?.. If the pump primes can i assume the relay is ok ? any advice appreciated.

David

 

[ducati]

I think what happpens with the 124 series is the pump primes with the first turn of the key but then will only run whilst the engine is actually running - so the pump won't be pumping if the engine stalls (this is why it is a relay rather than just wired into the ignition).

I may be wrong - I have heard a fair amount of b/s regarding fuel pumps/relays/filters etc.

 

[television]

With the ignition turned on the pumps run if the relay is OK they are a type of vane pump and any surplus is returned to the tank. The relay has a built in cut out that stops the engine going over 4k in nuetral and max revs by cutting the fuel supply.

malcolm