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How can I repair a fuel pressure fault in my 2000 BMW 530D SE Touring?
What is the best way to solve starting difficulties due to "low fuel pressure delivery" (per diagnostic machine) in my August 2000 BMW 530D SE Auto Touring?
Asked on 30 July 2010 by loughrigg lad
Answered by
Alan Ross
Low fuel pressure is an area in which most fuel supply problems occur. This could be poor fuel supply to the rail/injectors, or the rail/injectors are not holding the fuel within the system. It's best to look at three areas.
1. Low pressure supply from the tank to the high pressure pump (HPP). Some systems rely on the HPP to suck fuel from the tank, whilst others have an electric pump in the tank or fuel line to supply fuel to the HPP. Supply from the tank to the HPP should be about 2 to 5 bars pressure.
2. Fuel is delivered from the HPP to the rail/injectors at about 200 bars during cranking/300 bars during idling.
3. Once the fuel is delivered to the rail/injectors at the relevant pressure it must be maintained within the injectors/rail.
1. Low pressure supply from the tank to the high pressure pump (HPP). Some systems rely on the HPP to suck fuel from the tank, whilst others have an electric pump in the tank or fuel line to supply fuel to the HPP. Supply from the tank to the HPP should be about 2 to 5 bars pressure.
2. Fuel is delivered from the HPP to the rail/injectors at about 200 bars during cranking/300 bars during idling.
3. Once the fuel is delivered to the rail/injectors at the relevant pressure it must be maintained within the injectors/rail.
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