Do we really have control over the FSCM? 2010 CTS-V

[justhereforinfo]

2010 CTS-V 6sp Automatic.
Headers, no cats, 2.55 pulley, Airaid intake, FIC1200cc injetors, dsx flex fuel, cooling mods, and I just added Deatchwerks DW300 dual drop in replacement fuel pumps.

Initially my (stock pump) FSCM tune, the High Flow Mode commanded is 70 psi, normal is 50psi. This caused the new fuel pumps to instantly shoot to 100% duty cycle and overshoot the targeted FP to 99psi and throws code p069e. I've editted the FPCM tune, by reducing the High Flow Mode FP to 60psi (plenty of injector for this). As you can see in the logs, my commanded FP and actual FP are dead even at 60psi, until suddenly for some odd reason unknown to me, the fuel pump DC jumps to 100% and my FP shoots to 89psi.

From there I've lowered the Fuel Pump Openloop Duty Cycle tab so that the highest value is 80%. I flashed the tune and it made no difference at all. Goes straight to 100% whenever it wants to. After speaking with Justin White, he tells me this is common and he has tested it on all 12 CTS-V operating systems and there is nothing we can do about it.

So my question to HPTuners, you advertise that you've unlocked the FSCM, but do we really have control? Is there something else controlling the FP duty cycle that we dont have access to on this platform?

Damn, sorry I don't have my latest tune file. I will upload when I get to my other laptop. I've also added Instantaneous Fuel Flow to my scanner for future use.
DW300 WOT spike.hpl

Check out the FP riding perfectly and then it just shoots to the moon...

Edit: Here's the tune. Remember, my injectors are scaled by 50%. CTSV with FPCM DW300 pumps 60psi cranking.hpt

[PGA2B]

Common issue when replacing fuel pumps.

Check out this thread on CTSVOWNERS From Jesse and Adam:

https://www.ctsvowners.com/threads/r...-notes.156276/

There are also several other threads on this:

https://www.google.com/search?q=ctsv...hrome&ie=UTF-8

[justhereforinfo]

Common issue when replacing fuel pumps.

Check out this thread on CTSVOWNERS From Jesse and Adam:

https://www.ctsvowners.com/threads/r...-notes.156276/

There are also several other threads on this:

https://www.google.com/search?q=ctsv...hrome&ie=UTF-8

While I have read Random's note many times, they mostly focus on tips to increase FP, or keep it up. I'm trying to keep it stable. But, I did just think of something to try. He seems to think High Flow mode triggers 100% Fuel Pump Duty Cycle. I want to avoid this, as the DW300 pumps and 90psi PRV create too much pressure I will test this today by changing my tune so that at idle and cruise i'll be in Low flow, and then WOT will use Normal Flow, instead of High Flow mode.

[BigTuner]

While I have read Random's note many times, they mostly focus on tips to increase FP, or keep it up. I'm trying to keep it stable. But, I did just think of something to try. He seems to think High Flow mode triggers 100% Fuel Pump Duty Cycle. I want to avoid this, as the DW300 pumps and 90psi PRV create too much pressure I will test this today by changing my tune so that at idle and cruise i'll be in Low flow, and then WOT will use Normal Flow, instead of High Flow mode.

I was going to suggest trying this, let me know how it goes.

[justhereforinfo]

CTSV with FPCM DW300 pumps 60psi cranking DC80 Normal Mode.hpt
DW300 Normal Mode.hpl

Ok, in this tune file I have raised the fuel flow values to Max in the High Flow Mode tab, so it will never go into High mode. I've set the Low Flow Upper values to what I usually see when entering boost, call it 50lb/hr. So Low is set to 50psi and Normal mode is commanding 65psi. You can see in the log, the FPCM does not care what mode you are using, it shoots right up to 100% and Fuel pressure sky rockets.

I also lowered the max value in the open loop DC to 80%, and it doesnt care.

Is there a table we dont have access to?

[CaudleDynamicsLLC]

Was about ready to install a dual-fuel-type system and commit a credit to unlock my FPCM to do some custom controls but was worried about the same thing - not having full visibility/control. lurking to see how this turns out!

[justhereforinfo]

We seem to have great control over the stock pumps, but the aftermarket pumps maybe are hypersensitive to voltage.. not sure. I gave up and re-installed the stock Pressure Relief Valve in the pump assembly. The Deatchwerks kit contains a 99psi relief, and the stock is 72psi. I've changed my tune back to normal, except in High Flow mode, I command 65psi and of course the Fuel Pump DC goes to 100% and I get a steady 72psi tapering off to about 69psi at redline.

If it were not for the internal relief valve bleeding pressure, it would be 99psi. This sounds like it will shorten the life of the pumps, and is possibly why guys see failures. It is better than the low fuel pressure and lean condition I had before so... Fixed is fixed.

I've tuned out the p069e and p0231, since the FPCM is not seeing what is commanded, and is freaking out.

[mememe123]

You should be seeing ~89psi, and it will spike to ~90ish right after WOT. Due to us having a non return fuel system there is nowhere for leftover fuel to go. Just don't lower it too much, because injectors still need pressure for proper atomization/spray pattern.
I believe people had some lean issues originally with stock FPV, and that's why DW made their own ~99psi one.
This is my understanding on this, since it's not really talked about, and people that know don't really want to share the info, minus a few posts that most of us have read through already.

[justhereforinfo]

So my question for HPTuners Support Team becomes: At what point does the ECM/FSCM decide it needs to go 100% dc to the Fuel Pumps, and is this table accessible?

It's not Flow Mode specific. It seems to be directly tied to Fuel Flow Estimate pid. But there is no table for that to adjust.

[justhereforinfo]

Yea, thats about what I was seeing with the DW PRV. At my power level (600ish), and fuel consumption level, I decided to go back to the stock PRV, and I'm seeing 72-69psi. With 1200cc injectors, and 13 pounds of boost it seems to be working well. If I ever decide to make real HP (800+) then I can swap the DW PRV back in if FP starts dropping.

[Ctsv_96]

Any luck with this situation? currently have dw pumps and car keeps throwing p0231 and fuel pressure command is always at 100% causing the car to turn off the secondary pump and trigger the code.