Losing fuel control in upper RPMs

[tvanlant]

I've been fighting this problem for months now and can't figure it out.

Issue: Leaning out 6600 rpm. Fuel pressure holds at 50+psi throughout the pull.

The car will respond to tuning changes below 6600, but no matter how much the MAF frequency is changed, it will not change above 6600.

I've tried:
Changing the load by adjusting the injector scaling, engine displacement and MAF curve.
Moving the MAF location to read less air.
Changing anything & everything in the tune that I could think might affect fuel contol.
21V BAP


My setup: Stock engine, E85, bosch 105lb injectors, KB 18V BAP, 10 psi with a Procharger D1SC, ~650rwhp


Here is the datalog:
https://www.mediafire.com/?gvrdelw2cku5knc


Any suggestions would be greatly appreciated!

 

[Voltwings]

If i'm looking at this right, your MAF frequency is incredibly turbulent, and your AFR's are kind of all over the place during this pull. Typically as you accelerate your MAF readings should steadily increase as your motor ingests more air. Your Voltages tend to bounce in this pull, and your AFR's bounce anywhere from mid .7's to high .8's / low .9's ... I Dont know if it has to do with your procharger set up's MAF placement, Which im assuming is a blow-through configuration, but it is an issue. The Odd thing is when it leans out your AFR's are almost more consistent than the rest of the pull... i'd almost check for something silly like actually commanding the right fuel targets in that region. Shit happens you know, gotta go back and check the basics.

 

[tvanlant]

Thanks for reviewing. I think you might be looking at sections of the log that aren't during the pull (the log starts a bit before the pull and runs a bit after the pull).Highlight the RPM pid to see where the actual pull begins and ends.

 

[Voltwings]

Derp, you're right haha, i just glanced at it real quick. Trying to do this subtley at work.

Well, i retract my previous statement ... i have no idea man. Seeing as how the Short terms are trying to add fuel and its not richening up, i'd say theres a mechanical issue somewhere. I believe the short terms have authority up to like 40% adjustment, and yours only go up to 14% or so, so it should be well within the computers means to add fuel if it could.

I'm just going off my basic tuning knowledge and experience, i dont really have any experience tuning Coyotes directly, so there may be some background logic im not understanding.

 

[tvanlant]

Yes, the short trims show how the tune is very close (3-5% correction), then at ~6400 the A/Fs lean out and the short terms are showing up to 15% correction needed, but it won't respond to any correction in the tune.

So...
1. It is running out of fuel.
2. Something in the tune is overriding the commanded Lamda of .80


Problem #1 seems unlikely due to the fact that it's holding fuel pressure at the rail, and I'm not anywhere near the HP limit of the typical stock pump/BAP. And I've tried a 21V BAP and it leans out exactly the same, at the same spot.

 

[Steveespo]

Restriction in the fuel line. Maybe some gunk from the E85. Sounds like you are mechanically short of fuel volume, you have pressure so maybe it is pushing against a blockage.
Just a layman's view, not a tuning guru by any means.
Steve

 

[wile2k]

What are you tuning / logging with?

My first thought was that it is using open loop tables and not actually responding to O2 feedback. The newer Mustangs aren't supposed to do that though, it should be closed loop at all times. Odd thing in the log is that it has a flag for "open loop status" which switches to "1" shortly after you go WOT on the pull.

I've been messing with the HPTuners beta but I'm not intimately familiar with the Ford parameters yet. Do you recall changing something that might have affected that?

 

[04compgt]

This is perfectly normal and can be adjusted in the tune, the returnless system has no way to adjust fuel pressure as boost goes up like a vacuum referenced return system with a boost reference regulator. A returnless fuel system has no way to raise fuel pressure as boost goes up. But you can adjust this fueling in the tune.

 

[tvanlant]

So I put a different stock pump in and it appears to be a bit stronger. .. it doesn't start leaning out until 6900 now.

Other than changing the MAF tf and the desired lambda at wot, what can I do in the tune to compensate for the pressure drop?

 

[SStampede]

Are you running a boost-a-pump?

SStampede.

 

[Ill_W1N]

What kind of bap are u running? If its jms set the dial to 75 which should be around 19.5v. Setting it to 100 was causing a similar issue with my friends car.

Edit:your op is throwing me off, you said your running an 18v kb bap then u said a 21v... Not sure which one it is. Jms is the only 21v i know of.