Fuel Pressure Dip - Deutschwerks Fuel Pump - PWM Ctrl

Jason Bentley
Posts: 29
Joined: Sun Jul 02, 2017 6:17 am

Fuel Pressure Dip - Deutschwerks Fuel Pump - PWM Ctrl

Post by Jason Bentley »

Does anyone have any experience with this Deutschwerks DW440 fuel pump, configured for PWM control? We're experiencing a dip in fuel pressure (see attached log). We are controlling the PWM with output/pin A20 and have tried with and without a 1k ohm pullup resistor across 5v and the pwm signal. We've also tried multiple PWM frequencies, per the pump manufacturers suggestion.


Brushless_Pump_Controller_-_DWC1_rev_1-3-22.pdf
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Attachments
Vandervlugt_v35_fuel_pump_logging.SD
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nmerdan
Posts: 30
Joined: Mon Jan 27, 2020 7:40 am

Re: Fuel Pressure Dip - Deutschwerks Fuel Pump - PWM Ctrl

Post by nmerdan »

What ECU do you have? Post your calibration or at least the relevant fuel pump tables.
Jason Bentley
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Joined: Sun Jul 02, 2017 6:17 am

Re: Fuel Pressure Dip - Deutschwerks Fuel Pump - PWM Ctrl

Post by Jason Bentley »

It's an S7 Plus. A better log is attached (has pump1duty).
Vandervlugt, Jason S7-Plus- 1.693 1200cc v41.SC
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Vandervlugt_v41_warmed_up (1).SD
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stevieturbo
Posts: 1321
Joined: Sun Dec 07, 2008 2:04 pm

Re: Fuel Pressure Dip - Deutschwerks Fuel Pump - PWM Ctrl

Post by stevieturbo »

The advert for the controller seems to suggest the DW440 is a dual speed pump, not a PWM pump ?

And it mentions 68% and 100% ? Is it just that you trying to use 30%, the pump or controller just isn't happy ?

Or is it the C103 controller ? The instructions don't seem so clear, and which one do you actually have ?

I just PWM my fuel pumps via a SSR and for the most part it seems to work ok. If it is a PWM pump/controller ok, have you tried a base higher duty ? I run mine at 38%.
Anything lower and they just didn't sound happy.
stevieturbo
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Re: Fuel Pressure Dip - Deutschwerks Fuel Pump - PWM Ctrl

Post by stevieturbo »

Although in the first log, you just have the pump ON ? no PWM ?

So it should be running at full power ? Can you hear the pump ? Does it sound any different when the dip is occuring ?
Jason Bentley
Posts: 29
Joined: Sun Jul 02, 2017 6:17 am

Re: Fuel Pressure Dip - Deutschwerks Fuel Pump - PWM Ctrl

Post by Jason Bentley »

stevieturbo wrote: Mon Jul 18, 2022 7:09 pm The advert for the controller seems to suggest the DW440 is a dual speed pump, not a PWM pump ?

And it mentions 68% and 100% ? Is it just that you trying to use 30%, the pump or controller just isn't happy ?

Or is it the C103 controller ? The instructions don't seem so clear, and which one do you actually have ?

I just PWM my fuel pumps via a SSR and for the most part it seems to work ok. If it is a PWM pump/controller ok, have you tried a base higher duty ? I run mine at 38%.
Anything lower and they just didn't sound happy.
We have it setup for PWM, using the C103 wire/controller. We confirmed there's no native pull-up on the controller itself and installed a pull-up ourselves, per Ryans suggestion. You can see out duty is around 30% (IIRC) in the latest log, which as you say, seems to be what the pump likes. As far as hearing any change on the pump - we do not hear any difference when the dip occurs. It's a brushless pump and everything on that system is pretty quiet when idling.

I do have experience with a fuel pump driven by a pwm signal to a hella SSR with no issues. I'm not sure what's going on here though.
stevieturbo
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Re: Fuel Pressure Dip - Deutschwerks Fuel Pump - PWM Ctrl

Post by stevieturbo »

The little Hella SSR's don't handle much current, realistically about 10A is their max. I use one for the water injection which is only short duty though. I wouldn't use it for a fuel pump.

Even in the first log though, Fuel pump status is simply ON ? and it still has the little dropouts ? So that would be at 100% duty ?

If you manually applied a ground to it, ie 100% does that make a difference vs the ecu's 100% ?

What about different control frequencies ? Does that make any difference ?
Jason Bentley
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Joined: Sun Jul 02, 2017 6:17 am

Re: Fuel Pressure Dip - Deutschwerks Fuel Pump - PWM Ctrl

Post by Jason Bentley »

stevieturbo wrote: Mon Jul 18, 2022 8:46 pm The little Hella SSR's don't handle much current, realistically about 10A is their max. I use one for the water injection which is only short duty though. I wouldn't use it for a fuel pump.

Even in the first log though, Fuel pump status is simply ON ? and it still has the little dropouts ? So that would be at 100% duty ?

If you manually applied a ground to it, ie 100% does that make a difference vs the ecu's 100% ?

What about different control frequencies ? Does that make any difference ?
Ideally, we need to scope the signal from the Syvecs just for some assurance that it's not an issue with the output/signal. I've asked the Owner of the car to purchase an affordable scope for this. Once I confirm the signal is good, then it's something on the DW pump side of things.

We'll try the manual ground test method - thanks.

We have tried multiple frequencies, but no luck and no difference from 100Hz to 10K Hz
stevieturbo
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Re: Fuel Pressure Dip - Deutschwerks Fuel Pump - PWM Ctrl

Post by stevieturbo »

Although not quite a scope, at lower duties it can work fine....

Log the "output"....on a spare input at 1000Hz

If you're applying say a 50, 100Hz output, it should display pretty good. Then you could use some time/measuring tools in SView if needed.

I've used spare inputs to mess about with in cylinder compression tests before both cranking and running. 1000Hz not ideal. Fine at cranking speeds, loses resolution quick at running speeds
stevieturbo
Posts: 1321
Joined: Sun Dec 07, 2008 2:04 pm

Re: Fuel Pressure Dip - Deutschwerks Fuel Pump - PWM Ctrl

Post by stevieturbo »

And FWIW, with a current clamp on my pumps that also gives frequency...it reads bang on 200Hz which is what I feed to the SSR with the PWM control with an open loop table
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