M5 Expert (>4000)
Join Date: Apr 2006
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Well, glad it at least worked for a couple of gears...
So, if F30 was blown, that's the power supply fuse for the primary pump. This pump is controlled by the DME sending a pulse-width modulated signal to the EKP module over a single wire interface. As torque demand increases, the pulse-width narrows and the EKP module response by ramping up the control voltage to the primary pump (also PWM, but for power control). Above a certain demand signal from the DME, the EKP module activates the secondary pump. The secondary pump is not PWM controller, but on-off only.
The blown fuse for the primary pump is a symptom, not a cause. If you have the old one and can measure the resistance across it to verify its blown, we confirm the symptom only.
The question becomes, what blew it? I haven't looked inside an EKP module, but I would imagine its pretty straightforward. A blown fuse could indicate either a problem with the primary pump itself, the EKP module, or the wiring in between the front fuse box and the EXP module (least likely in my mind). Whichever the cause, its pulling too much current through the fuse. Whatever the fault is, it's most likely associated with the primary pump. I'm not an advocate of the "guess and swap" Easter egg mentality of troubleshooting, but if I were to replace any component first, it would be the EKP module.
There is a fuel system diagnostic function in DIS/ISTA/INPA, have you run that?