Any general discussion around the firmware, what is does, how it does it etc.
I am still on the way for firmware upgrade for flex fuel (LPG Propane Etc.) and returnless fuel system with rail pressure sensor. anybody care with that.. as you know fuel is not cheap anymore in most countries like Uk Netherlands Turkey and Australia too...
returnless fuel system with rail pressure sensor.
This is of interest to me. Though I'm thinking PWM controlled fuel pump and NOT using any rail pressure sensor (may not be safe in boosted applications). This is implemented in other EFI systems - the catch is that the ECU is programmed to match the supplied fuel pump.... There would be a need for user input regarding the fuel pump max flow rate(at a known or configurable psi rating) depending on fuel pump application(s).

I doubt it would be anything other than a PWM (current) setting, and you have to test for correct pressure at that setting. Unfortunately, most of the cars with no sensor have other means to detect filter clogging or pump pressure loss, and consumption rate to control the pump. Speedy does not, and might not go so far as to use approximated consumption to extrapolate pressure, and therefore assumed pump current to meet it. Also, if fixed PWM was always running at full setting, there would be no current curve to change current during high or low demand like those OEM systems have, so the pump would have to run at peak level all the time for if the demand goes that high. In any case, a pressure gauge or test sensor would have to be used at least during setup to tell Speedy what PWM DC to use. As I certainly would want a real-time check on pressure, It would seem a sensor would be prudent to install for both operator info and potential future PWM control schemes.

For others reading this for new projects, be aware a large number of returnless systems are simply a pressure regulator with return in the tank providing a single line out, rather than up at the injector rail. Be sure which of the systems yours uses in order to choose the best way to control it.

Interestingly the s type jags have both returnless and intank regulator.
The ecu controls the pump via pwm from a module over j1850pwm bus.the ecu has a pressure sensor in rail to use for reference.
The regulator in tank is set at pressure max at max demand as a kind of failsafe you could say in case of a control failure.
Yes, that system is one example, and I have exactly that in one of my cars. Effectively, it is PWM controlled to simply reduce pump loads, pump and electrical wear and tear, and reduce fuel heating compared to running at 100% as previous MAP-referenced regulator systems did. Most of this type reduce the pump current to a level slightly higher than required by the bypass regulator, so it's just like without PWM, but saving the pump and power. This type of system would be fairly simple to incorporate with Speeduino, as the resulting controlled pump flow is not critical to system pressure (the FPR handles that), but efficiency is increased.
Hello i have a simple question about this topic. As today there is no PWM control for fuel pump in speeduino, so i´m thinking in building one, using a arduino nano just for this job, using a pressure sensor to maintain a pressure of 3 bar (around 40 psi) and control my PWM for my pump.

The application would be fueling a single injector for a 250cc motorcycle engine, i´m planing to do this because i don´t want to use a pressure regulator or a return line, just one line from the tank to the fuel filter, to the pump and to my injector.

Can any one give me a inside if this can work? I m planing to use a commercial available fuel pump (from Honda XRE 300cc bike), on that bike the pump work at full speed, it has a pressure regulator and a return line (i want to get rid of this), my pump will overheat? It can be driven like my plans, with PWM ?

If anyone has some inside about this it will be deeply appreciated. :D
It has been done more than a few times, there was someone used to sell a very simple cheap controller meant for atv/bike pumps (edit found the link for that one )

Maybe this might give you some inspiration, nothing to do with me but saw it while browsing. ... 49766e8a2d
dazq wrote: Mon Apr 15, 2024 11:31 pm It has been done more than a few times, there was someone used to sell a very simple cheap controller meant for atv/bike pumps (edit found the link for that one )

Maybe this might give you some inspiration, nothing to do with me but saw it while browsing. ... 49766e8a2d
Hello brother! Thank you very much for the answer, you gave me more encouragement to build my injection system! :D :D
+1, the simplest solution without changes to Speeduino is an inline PWM controller to the pump. @dazq's link is one example, or a DIY version using the code link or your own brew. If looking for pressure regulation or increasing pump efficiency, I used VVT control on old code to control the fuel pump and rail pressure for testing. It's the same thing, just using a different data source.

It worked OK, but the new VVT code is much more complex and limiting. Point is, the basic functions might be integrated into Speeduino and TS for fuel pump control, to provide PWM control, either simple or PID. The methods used in Boost Control, VVT, PWM Fan, etc, could be lifted into the pump control code perhaps. This could be simpler(?) and maintain the flow and style of the current code. Same goes for alternator control, which I have also done, first as a standalone for testing. ;)
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