Fuel pump electric problem 450SEL

[bnunes39]

Hi, I have a 450 SEL , the engine starts at times and then cuts off, I tested the pump electric , it shows at times 3volt and at times around 6 volts, I applied electric from outside by cables the pump runs and the engine starts, but when connected to the wiring in the car the problem comes back, I replaced the relay in the fuse box, disconnected the plug on the airflow unit still same problem.
The pump , filter were replaced recently, fuel tanks replaced as well.
Please can someone advice, before I start to chase the wiring .


Thanks,
Sebastian.

[UTn_boy]

Sebastian, you have a wiring problem.  Get a wiring diagram and start chasing wires.