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Matt
Matt, Engineer
Category: Mercedes
Satisfied Customers: 20598
Experience:  Mechanical Engineer with 23 years experience in the auto industry, 8 yrs in formula 1 engine testing
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If the car was standing for a few hours, is struggles to

Customer Question

Good Morning, if the car was standing for a few hours, is struggles to start, I replaced the Fuel Pressure Sensor, but still the same.
JA: Are you certain it's the fuel pressure sensor that's in need of attention? What about the fuel rail? Have you checked it yet?
Customer: Injectors was overhauled recently, and they tested the rail.
JA: What is the model/year of your Mercedes?
Customer: ML270CDI 2004 model
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: Replaced the Fuel presure sensor, as it was the fault 2 years ago, and checked for leaks
JA: Anything else you want the mechanic to know before I connect you?
Customer: when the car is hot, and I accelerate, the engine cuts out and ECP light comes on, if I restart, it starts immediately and goes again.
Submitted: 22 days ago.
Category: Mercedes
Expert:  Matt replied 22 days ago.

Hello

I'd agree that its possibly a lack of fuel and could be a lack of fuel pressure from the electrical pump at the tank.

1st thing to try is to remove the fuel filler cap and then flick the ignition on whilst listening for the brief ‘buzz’ of the pump

If the connections to the pump are corroded or damaged then the pump could stop at any time or could not be running at full speed. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse,

Ideally measure the pressure at the entrance to the main engine pump (should usually be around 3Bar / 45psi +) and if this is low check the pump as described and also consider changing the fuel filter as if this partially blocked this too will reduce pressure.

Expert:  Matt replied 16 days ago.

Hi

do you still need help?

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