Advice from any fueling experts or anyone using a Mk5 R32 returnless fuel system wanted please. I have an issue where the Audi fuel filter with the integrated 4 bar FPR is letting over 4 bar to the rail after a while. This is making the car run very rich at idle and causing me running issues until I replace the filter. The last filter lasted a year. I'm running a lift pump from the MK1 golf tank to an external surge tank with a Bosch Motorsport 040 in the surge tank. This then feeds the filter /FPR in the returnless fuel system. I guess the issue is the Bosch pump is vastly overpowered compared to stock and the FPR can't cope with the pump, the return is bottled necked causing excess pressure to the rail. I've been reading up about how returnless pulse width modulated pumps from the factory now regulate the output. Is there anything I can purchase to make my Bosch pump work this way? I assume the PWM signal feed is from the ECU? Any help would be much appreciated before I start to look at a return system with the mk4 R32 fuel rail. Cheers Rich
What about a separate, adjustable, FPR after the pump to reduce the pressure before the integrated FPR?
Hi Phil thanks for the reply. I guess the only issue with that is I need to run a vacuum line to the FPR and another return. I might as well do the whole hog and install a mk4 fuel rail then.
You don’t need a vacuum line to the independent FPR (if that’s what you meant?). When I fitted one on my 911 it just sat in the fuel line, albeit on that car it was on the return, if I remember correctly. This is the sort of thing. Mine was Sytec. You could, in theory, do away with the integrated one.
Very much like this one. https://www.ebay.co.uk/itm/35283123...-5R887dR_G&var=&widget_ver=artemis&media=COPY
