A few questions about fuel pump pwm

[techno]

Hello! I have several questions about connecting a fuel system with PWM pump control on ms3pro evo

I want to use a Ford FPDM unit to control two 380lph pumps. Explain how to properly connect the wires to ms3? I read a lot of posts about the pull-up resistor, but English is not my native language, I can not understand the sequence of connections.

Will this module suit me? and if it's not difficult to draw a diagram with wiring on ms3

[goodysgotacuda]

Tagging. I have set this up on an arduino successfully.

You are aware of the 50% duty cycle and frequency requirements?


Sent from my iPhone using Tapatalk

[techno]

Tagging. I have set this up on an arduino successfully.

You are aware of the 50% duty cycle and frequency requirements?


Sent from my iPhone using Tapatalk

I know that the block multiplies% of the load, but did not understand about arduino ... Perhaps it would be easier to use a solid state relay? In any case, I need an approximate connection scheme, so far I can not figure it out using the translation

[goodysgotacuda]

Here is what I know..

FPDM - Pin chart as tested.JPG (118.26 KiB) Viewed 2085 times

I ran a bulb and fan off of this

https://www.youtube.com/watch?v=R7-KgCiqUbQ

[vw_chuck]

Dude run a Dorman 902-310 SSR. It is a 40 amp solid state relay. Low side drive just like a normal relay. None of that Ford clusterfuck above.

[techno]

and yet which scheme is better to use?

if ssr, then how to connect control - + or -?

[vw_chuck]

The SSR I posted uses lowside drive or negative control. Just like a normal relay.

[techno]

This is the right scheme? I heard that I need to add a diode, but I can not understand where. Mark the missing items on the diagram pls

[mjhughesgt]

Dude run a Dorman 902-310 SSR. It is a 40 amp solid state relay. Low side drive just like a normal relay. None of that Ford clusterfuck above.

I recently bought on of these, and I'd like to confirm the wiring to the MS. Do you send +12v to the signal wire, and then let the MS PWM the ground side? Really, I'd just like to make sure that the module isn't expecting +5v. Would hate to burn it out. Thanks.

[vw_chuck]

You just hook up I believe pin 4 to the MS fuel pump signal and pin 3 just gets hooked to ground. There is NO 12vdc needed.

[OkayDriver]

One benefit of the Ford FPDM is that you give it a 150Hz PWM signal and it does the actual switching of the device (fuel pump in this case) at 10kHz PWM.

[mjhughesgt]

Thank you vw_chuck. You are correct! For the Dorman 902-310 module:
pin 1 - Fused +12V
pin 2 - Output to load
pin 3 - ground
pin 4 - Control wire (Megasquirt PWM to ground)

[OkayDriver]

Just as a follow-up on this, if you have a MS3Pro you can hook the Ford FPDM up to one of the Stepper outputs (either Stepper 1A or 2A should work fine with "Normal" polarity selected). The Stepper outputs will drive to +12V and ground to generate the required square wave. I bench tested this setup and it worked great with no pull-up resistors required. I thought that the Tach output might work as well, but I didn't have much luck with it. Anyway, depending on the resistance of the pull-up on the Tach output the Stepper outputs will probably allow less noise at the FPDM on the receiving end anyway (since they likely have a lower source impedance than the Tach output when it's pulled up to 12V).

I set the PWM fuel pump control with the following parameters:
Output: Stepper Out 1
Output Frequency: 150Hz (verified from stock Ford control signal)
Output Polarity: Normal (probably want to reverse this if using Stepper 1B or Stepper 2B)
Off Duty %: 75%
Minimum Duty %: 5%
Maximum Duty %: 50%

Also, for bench testing you can change the "Off Duty %" on the fly to whatever value you want and see the Ford FPDM do it's thing if you hook an 12V lamp, LED, motor, or whatever to the output of the FPDM.

Now if only I could figure out how to disassemble the silly FPDM connector without breaking it. I tried remove the white face piece and the terminals with my terminal removal set, but didn't have any luck without taking a risk of breaking something inside there. I'd like to locate the part numbers for the terminals they use so I can build a harness with new crimped on connectors instead of splicing into the stock pigtail I cut from the salvage yard...

IMG_1350.jpg (63.39 KiB) Viewed 1540 times