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Thread: 2017 Cadillac ATS-V. Attempting to drive a brushless fuel pump.

  1. #1
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    2017 Cadillac ATS-V. Attempting to drive a brushless fuel pump.

    I am trying to set up a DW440 brushless pump with the PWM controller on my vehicle. Currently I am using the grey power wire from the factory FPCM for my PWM signal.
    The DW440 pump controller looks for a low side pwm signal, the positive signal from the FPCM is ran through an optocoupler to handle the switching from positive to negative. Per the data sheet it should work up to 40khz (I suspect it isn't).
    Minimum duty cycle must be above 35% for the pump to remain powered, any signal above 90% and the controller defaults to 100%DC.

    So far I am able to command the pump to run via the VCM scanner and see that I can build pressure as high as 115psi. After flashing a map to the car the pump can be heard priming. When starting the car pressure can be seen spiking to ~98psi and then it drops immediately, pump stays off.

    Two codes are currently present, and somewhat expected. Fuel pump open circuit and fuel pump circuit high. I attempted using a load ballast resistor for a turn signal to appease the FPCM, pretty sure its not too happy about it.

    In an attempt to get the car to idle I have tried setting the minimum pump DC to 36%. Changed the cranking pressure to what I was seeing while logging a startup (95psi). Setting all pump duty cycle settings to 36%. Setting pressure maximums to 110psi. Setting the inferred regulation pressure to 110psi, and changing all of the desired fuel pressures.

    I'm starting to run out of ideas on how to get this thing to run. Information on the factory fuel pump control module is extremely limited, but it should be similar if not the same as the one used on the Camaro. I suspect what I am using to switch my positive signal to a ground signal might not be working as I had thought it might where it might provide a pulse once and long enough to fire the pump, but have a muddy signal after.

    Attached is a screenshot of a log taken while cranking the car. Fuel pressure goes from 43psi to 97 almost instantly, and then just drops off to zero.

    Any information would be a huge help.
    fuel psi1.png

  2. #2
    Those codes being present, as you pointed out, suggest that the FPDCM doesn't like the feedback its getting from the fuel pump. Once the diagnostics fail, all bets are off. The FPDCM in these vehicles is not programmable, so unless the diagnostics are processed in the ECM and can be modified, this isn't likely to ever work.

    If you disable the two codes that are setting, does that change anything?

  3. #3
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    Quote Originally Posted by tunerpro View Post
    Those codes being present, as you pointed out, suggest that the FPDCM doesn't like the feedback its getting from the fuel pump. Once the diagnostics fail, all bets are off. The FPDCM in these vehicles is not programmable, so unless the diagnostics are processed in the ECM and can be modified, this isn't likely to ever work.

    If you disable the two codes that are setting, does that change anything?
    I'll try disabling the codes and report back.

    Another email from deatschwerks today suggested that even at 50% duty I'm likely to not see much flow. ~140lph at 60psi at 50% duty.

    I am able to see that the computer is still requesting pressure after it drops off, any attempts to log duty cycle has been unsuccessful. I might not be setting up the tables in VCM Scanner correctly though.

  4. #4
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    Reporting back.

    Still no luck after disabling the codes. Just cant seem to make the FPDCM happy. I still believe it to be possible, but I'm going to shelve the project for now.