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High FPDC readings


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Ive read a few different threads about this already but none with the exact problem im having and none of the solutions they had worked for me.

 

im running

DW65c pump

DW50cc injectors

2007 Spec.B

 

My Fuel pump duty cycle hits 100% at startup then after a few seconds and a blip of the gas pedal it drops to 66%. under almost any load it jumps back up to 100%.

 

I know i dont need nearly that much flow for the setup im running and that %100 duty cycle on any fuel pump isnt good for the pump. Its my understanding that they usually run in increments of 1/3's. so 66% at idle seems a bit overkill as well.

 

i first inspected and cleaned the maf with no change. i checked for air leaks and fuel leaks with no luck. all the electrical connections on the fuel system seem to be in good condition. next im going to pull the pump and inspect the filter and housing units for cracks.

 

has anyone had any experience fixing this issue? what else can i check? could it possibly be the fuel pump control unit? how could i test that?

 

:confused::confused:

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They always start at 100% and will always be at 100% under load. 33% at idle and full operating temp. Unless you are having a fueling issue you are overthinking it. 100% command is not 100% duty cycle. 100% duty cycle is 100% all the time. Which is done rather often (hard wiring the fuel pump) and has no major noticeable difference in pump life.
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No electrical or mechanical connections will change any of what you're logging, the FPDC is effectively run open-loop by the ECU, and only changes in certain conditions. Like m sprank says, if you don't have any fueling issues, don't worry about it.
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FPDC is decided by the hotstart status, fuel injector duty cycle, and manifold pressure. As Soledxsnake says, it runs open loop.

 

Unless you have issues with sensors (coolant temperature or MAP sensor) FPDC isn't anything to worry about.

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Talked to my tuner.

 

Turns out the previous owner had a failing dw65c and asked the tuner to just run it regardless.

 

i replaced it with an aem 320lph and currently etuning with the tuner.

 

also fixed a bpv boost leak.

 

i feel like there is going to be more fuckery to uncover from the previous owner haha

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