Mini R56 fuel duty cycle

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Joined: Fri Aug 11, 2023 6:34 pm

Mini R56 fuel duty cycle

Post by Mattst3lantis »

Hi All

After a break from the trade, I’ve gone back to what I enjoy ( well until this weeks head scratcher anyway! )
We have had a 2007 mini R56 Cooper S brought in, from another garage with the usual HPFP issues, other than it’s on its 3rd HPFP, and still not fixed!!!
Initially checked supply, diag revealed an actual pressure of between 0.65 and 0.70 mpa ( pretty much tank pump pressure) , target pressure should be around 50 bar at idle , and fuel valve duty showed 5% with a brief increase to 15% , actual pressure raised a little, then ecu goes into limp mode with the 2880 fault code for high pressure system triggered.The specified value and duty then go to zero, and car runs better as In default. Checked in tank pump 5 bar at idle, and holding pressure for 10 mins between 4-5 bars when engine off. At this point would have suspected the HPFP itself, but with the history, decided to check further.It seems that the ecu will not increase the duty cycle to the fuel delivery valve initially in order to build pressure, which then in turn causes the fault code, and deactivate the control. Checked the supply’s to control valve with scope, and confirms little difference in the output from ecu, supply voltage is >12v at all times, current HPFP is new from a trusted supplier, previous pump was allegedly new from Peugeot (same pump ). , and original pump does exactly the same thing too! Also swapped tank pump for another pump just to be sure!
Rail pressure sensor seems ok, and have even tried another ecu which was available, with same results.
Has anyone else experienced similar issues or have any suggestion as to the lack of pressure?
Many thanks

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