03-16-2012, 08:14 AM
Join Date: May 2008
My Ride: 2003 330Ci
| The description of your starting issue after sitting for 30 minutes sounds like it could be a problem with the non return valve in your fuel pump.
You can test this by checking the fuel pressure, it should be 50psi +- 3 psi with the engine idling. the pressure should be retained when the car is turned off.
Description of operation: pressure retaining function
The pressure regulator closes when the engine is at a standstill and the ignition key is in position 0. The fuel pressure in the delivery line is retained over an extended period. A non-return valve closes in the fuel pump. These measures help to retain the fuel pressure in the fuel system. Extended starting times are thus avoided.
Complaint: starting problems
- Run engine briefly at idle speed and switch off.
- Note down measured value while engine is stopped.
- Read off measured value again after approx. 20 to 30 minutes while engine is stopped.
Special tool 13 3 010 (hose clamp) is required for the following test.
If the measured value has dropped by more than 0.5 bar:
- Start engine and wait briefly for a stable pressure increase.
- Switch off the engine and immediately pinch off the delivery line just before the pressure gauge with the special tool 13 3 010.
- Note down measured value
- Read off measured value again after approx. 20 to 30 minutes while engine is stopped
If the measured value has now dropped by less than 0.5 bar, the following faults can be present:
- Fault in delivery lines
- Fault in in-tank delivery hose
- Faulty pressure-holding non-return valve in fuel pump
Check components. Replace faulty components.
If the measured value has dropped by more than 0.5 bar again:
- Replace pressure regulator
Discounts on new and CPO cars.
Most Dealers offer a parts discount, BMP Design 10% off