Fuel Pump Problem
 

Hy to everibody and thanks for all information in this forrum.
my car a CLK 430 1998 last week decided to die and it was the fuel pump.
After some test i decided to change the pump with one new MB and the filter , the car started again even if it takes some times before turning with 8 cil..
Now the car seem to run weel but ti can hear some little noise from the fuel pump like ''Z-ZZZZZ-ZZ-ZZZZ-Z'' i mean that the noise is not constant abut intermittent and not reular.
So iwas thinking that tha pump was sucking some air ^while the internal pipe inside the tank ,for this i filled at max the tank and tried.......the noise is the same.
tha car seem tho miss some power only between 5000 and 6000 rpm but i ma not suer because i ma really not used to drive klike this..
i would like to ask if sombody can tell me where is the FUEL PUMP RELAY in this way i willl chek if the power supply is good.
Can someone help me? Do you have some more test to suggest me?
Many thanks
Alberto

Relay Fuel Pump................
 

Sorry may be my English + explications are too bad..........