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    PWM Fuel Pump Control - learn me

    Guys, leading from my last post in this section re a lower capacity fuel pump for my purpose, I think I am better off solving the root cause of the issue.

    I am running a DW 250il fuel pump as the main pump internally within a DW surge. It is a returnless set up so feeds a fuel pressure regulator ~6" away, as such the return from reg back to surge tank is only ~6" long. This 250lph of pump is going full blast at all times and it is damn loud, it's also far in excess of what is needed which would be ~ 150lph ay WOT let alone just cruising around. Subsequently the pump/fuel is getting quite hot, if idling at the lights for a while the car will stumble when taking off.

    So, I'd like to be able to control pump speed. I am running a Haltech Elite 750 and I am out of outputs. I know nothing as to how the PWM would work, what ones I should be looking at etc? I imagine I will also need to be purchasing an IO expander.

    Any help would be greatly appreciated.

    Sam
    Rust is lighter than carbon fibre.

    My Italian 510

    #2
    Enter Burns_is_weird.....

    Essentially you will need a free PWM output (surely something can be removed from the 750?) and the ECU will vary the duty cycle with engine load so that the flow always slightly exceeds the demand.

    You could use one of those fancy new feedback pumps $$$, re-purpose an existing output (maybe?), buy an IO expander $$$, or trade up to an elite 2000? $$

    https://fuelab.com/product-category/...re-regulators/

    Burns has the hookups for a decent controller if you want to do it via the ECU. or i can point you to a cheap one that i use for my thermos (not sure if i'd trust it with fuel delivery) Dorman 902-310

    Comment


      #3
      Thanks for that. I have seen those feedback pumps, but holy shit it is expensive. Going for the IO expander I can also then use my combined oil temp/pressure sensor, currently only running pressure.
      Rust is lighter than carbon fibre.

      My Italian 510

      Comment


        #4
        Someone who knows will elaborate but you need high speed pwm or you can fuck out the pump.

        How I am doing it in a commodore I have is Vapour Worx kit it runs pressure feed back and increases and decreases pwm toget fuel pressure with no reg. They use a jet to "leak" enough fuel for the car to idel.
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          #5
          Couple of ways to do it man,

          1. Solid State Relay - can use a seimens/Jaycar SSR. They are rated to 30a (off memory) so a single Walbro will have no issues.

          2. Fuel Pump Controller. There are a few choices here, used Subaru ones I know some people use. NZEFI sell a jaguar/ford controller too.

          Yeah you will need a PWM digital out. Send youap to me maybe there is something we can swap/move. IO expander is a expensive solution but I guess if you want more io anyway..

          Comment


            #6
            Can recommend the range rover/continental controller. You only need a 100hz ecu output and it up samples to 20khz or something. Effectively DC voltage control and has a decent capacitor in it. Both the neg and pos go through the controller so it handles flyback etc.

            Even eats 18v and 20a so is OEM reliable. Had mine for years.

            It's the same as the NZ EFI one. Part number is 7h42-9d372-aa or 7W83-9D372-AA can be had cheap on eBay. I think I paid about 60 bucks.

            Nzefi link: https://www.nzefi.com/product/fuel-p...ed-controller/

            I've got a bunch of the plugs and pins for it. Had to buy 5 as it was min order quantity. It's a Yazaki connector 7283-5577-10. Took me fucking ages to find that out. Let me know and I'll post you one with some pins for nothing.

            Looks like this
            Last edited by burn is weird; 11-12-20, 11:28 AM.

            Oo___oO

            Comment


              #7
              Originally posted by burn is weird View Post
              Can recommend the range rover/continental controller. You only need a 100hz ecu output and it up samples to 20khz or something. Effectively DC voltage control and has a decent capacitor in it. Both the neg and pos go through the controller so it handles flyback etc.

              Even eats 18v and 20a so is OEM reliable. Had mine for years.

              It's the same as the NZ EFI one. Part number is 7h42-9d372-aa can be had cheap on eBay. I think I paid about 60 bucks.

              Nzefi link: https://www.nzefi.com/product/fuel-p...ed-controller/

              I've got a bunch of the plugs and pins for it. Had to buy 5 as it was min order quantity. It's a Yazaki connector 7283-5577-10. Took me fucking ages to find that out. Let me know and I'll post you one with some pins for nothing.

              Looks like this
              Do this Sam!

              Will work a treat

              Comment


                #8
                I used a SSR and the PWM output from my adaptronic that was supposed to be controlling wategate solenoid. Shuts the noisy 044 up a fair bit at low rpm.

                PWM output for wastegate is, well, wasted on my roots supercharged application now innit?

                Comment


                  #9
                  If all the electrics is getting too hard, what about the return line back to the tank for now.
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                  Comment


                    #10
                    Seems a lot of headaches instead if shopping around for another pump or submerging a intank pump in a surge tank.

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                      #11
                      Thanks guys, really appreciated. I did come across that NZEFI one when searching. Looks like a winning option.

                      Originally posted by Dogsballs View Post
                      Seems a lot of headaches instead if shopping around for another pump or submerging a intank pump in a surge tank.
                      Sent from my HTC One M9 using Tapatalk
                      This is a pump submerged in a surge tank. No other pump type will work within this surge tank. Another pump is going to mean an external (likely Walbro GSL193) which means pump purchase, fittings and line and perhaps perhaps fab work for the existing fuel pump bracket. And once I’ve spent all that money there’s still the risk of having a noisy pump that is over heating the fuel.

                      Of course a lot of these issues could have been solved in the first place if I had of designed the fuel system differently. But very limited room in the bay meant a returnless system was the best option, I didn’t want a cell and the OE tank design doesn’t lend itself to easy conversion with an aero motive hanger or hydramat.
                      Rust is lighter than carbon fibre.

                      My Italian 510

                      Comment


                        #12
                        Originally posted by 200MPH View Post
                        I used a SSR and the PWM output from my adaptronic that was supposed to be controlling wategate solenoid. Shuts the noisy 044 up a fair bit at low rpm.

                        PWM output for wastegate is, well, wasted on my roots supercharged application now innit?
                        I had the same setup and it worked really well. Wiring is simple. As per the Range Rover one above you do need a decent heat sink or mount solidly to metal as they get pretty warm
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                        Comment


                          #13
                          Originally posted by Guido View Post
                          Thanks guys, really appreciated. I did come across that NZEFI one when searching. Looks like a winning option.
                          You dont need any extra IO.. if using a pump controller, you can feed the pump control module switched ignition power (this frees up your fuel pump signal DPO on the ECU). you convert the Switched DPO your pump is using to a PWM output in the haltech config and wire that to the FPCM/SSR. then use the Fuel pump duty cycle table to control the pump speed and have "fuel mass flow" as the axis and MAP as other axis (dont use injector differential pressure as you introduce a control feedback loop). then scale pump speed as required to maintain fuel pressure.

                          also if you go the SSR route please use a flywheel diode accross the pump +/-. at higher frequencies it a decent amount of energy and a naked MOSFET SSR can be damaged. an OEM grade FPCM is a better solution.
                          Last edited by burn is weird; 11-12-20, 11:09 AM.

                          Oo___oO

                          Comment


                            #14
                            Thank you so much! I'll track one down on fleabay and take up your offer on the plug and pins.
                            Rust is lighter than carbon fibre.

                            My Italian 510

                            Comment


                              #15


                              thats mine with speed mapped to TPS for testing

                              and this is why engineered OEM is better than just a solid state relay. inductors and capacitors inside the unit.

                              Last edited by burn is weird; 11-12-20, 11:24 AM.

                              Oo___oO

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