Running out of fuel?

Audiophyle
Posts: 76
Joined: Sun Aug 18, 2013 8:16 pm

Running out of fuel?

Post by Audiophyle »

I keep running out of fuel in boost and it doesnt seem to matter how much fuel I add the AFR remains the same, and this section of the fuel map goes dangerously lean. Is there something I am missing here? Off boost driving seems to be fine at all RPMs.

https://www.dropbox.com/s/hrj85zct8s0l2 ... t.JPG?dl=0
KTuner
Site Admin
Posts: 3744
Joined: Mon Jul 22, 2013 8:13 pm

Re: Running out of fuel?

Post by KTuner »

Use datalogging to spot anything that seems out of whack, if you think the ECU may not be receiving correct data from sensors. Beyond that I'd highly recommend contacting a professional tuner if you're getting stuck during the tuning process. We've seen what the factory ECU is capable of with a proper mechanical setup and you're nowhere near that level of power.
Audiophyle
Posts: 76
Joined: Sun Aug 18, 2013 8:16 pm

Re: Running out of fuel?

Post by Audiophyle »

Sensor data all seems accurate, 650cc fuel injectors are new (& have been flow tested), fuel pump & filter are new (using 265lph DW pump), and I am at a loss for what else to check. General consensus from other tuners is run ridiculously oversized fuel injectors (1000cc or larger), or upgrade to a return-style fuel system (typically required at 450hp+ & I am still below 250hp), & to ditch KTuner for Kpro (rolls eyes) or Haltech. All of which I do not believe to be valid or worthwhile suggestions. The setup I have should be more than adequate for my current system goals, so I must be missing or overlooking something.

I was hoping the datalog screenshot might provide insight into what the issue could be, and am just looking for ideas to follow up on.

How are the injector duty cycles calculated? I am seeing 17-18% at most when I hit this lean condition and that doesnt seem to change like I would expect when I am increasing fuel by 20-30% at a time based off lambda table values. At 8psi & ~4k rpms my fuel map values are now almost maxed out & I would expect to see the duty cycles nearing their maximum too.

How does the injector sizing setting work? Currently it shows 310 as stock & 650 as the new size, but it does not seem to change the fuel map values so is this just a blanket scalar value? What would happen if I changed it to read 600cc or 700cc as my injector sizing while using 650's?
KTuner
Site Admin
Posts: 3744
Joined: Mon Jul 22, 2013 8:13 pm

Re: Running out of fuel?

Post by KTuner »

The calculation for injector duty cycle can be found online easily. It's a simple formula.

You can see the base fuel value and final fuel values to ensure everything is following as you expect.

Injector sizing calculation is simple division so you can easily do the math to see how final fueling is affected. Applied globally.
Audiophyle
Posts: 76
Joined: Sun Aug 18, 2013 8:16 pm

Re: Running out of fuel?

Post by Audiophyle »

Okay, so it looks like the fuel values are not changing as expected.

At the start of the pull the Base Fuel Value is at 6000 & is running a little rich.
https://www.dropbox.com/s/e2qle1thhbssz ... l.JPG?dl=0

Through the pull the fuel table values go from roughly 6,000 to almost 60,000 but the Base Fuel Value remains consistently hovering around 6000 the entire time.
https://www.dropbox.com/s/sf5flz003rh4b ... g.JPG?dl=0

Every drive the lambda tables tell me to add 20-30% more fuel, and after a couple rounds the fuel tables hit the ceiling (65,535).
The engine should be drowning in way too much fuel but it is clearly not, and would explain why the injector duty cycle is not increasing either (because fuel values are not increasing). This would also explain why every datalog appears the same, because regardless of the fuel changes I make it seems the actual fueling is not changing so it just keeps asking for the same amount of fuel.

Why is this not working?
KTuner
Site Admin
Posts: 3744
Joined: Mon Jul 22, 2013 8:13 pm

Re: Running out of fuel?

Post by KTuner »

Did you start with a forced induction base code?
Audiophyle
Posts: 76
Joined: Sun Aug 18, 2013 8:16 pm

Re: Running out of fuel?

Post by Audiophyle »

Of course, isn’t that the only way to get boost support enabled?
KTuner
Site Admin
Posts: 3744
Joined: Mon Jul 22, 2013 8:13 pm

Re: Running out of fuel?

Post by KTuner »

You actually have full control of the columns at the top, so they could have been altered on a standard codebase.

I don't have any suggestions. If you're on a forced induction base code it wouldn't be stopping at atmospheric, so try to correlate it with something else. You are still using PRB I'm assuming.
Audiophyle
Posts: 76
Joined: Sun Aug 18, 2013 8:16 pm

Re: Running out of fuel?

Post by Audiophyle »

This is the PZD MT with forced induction base for the Element, adjusted for larger injectors and only a couple settings changed for operability. If this doesn’t work then it means your base tune for boost does not work.

The PRB base has completely different VCT tables, so I am reluctant to us it as a base platform

The Element only goes to 20* VCT with 0*, 10*, & 20* CCAM angles. The PRB cam tables don’t directly compare, so the only way I can tune for 10* VCT is by interpolation between the 0* & 15* tables, and to then tune for 20* VCT I have to do the same between the 15* & 30* tables. This just seems impractical compared to using the PZD base.
Audiophyle
Posts: 76
Joined: Sun Aug 18, 2013 8:16 pm

Re: Running out of fuel?

Post by Audiophyle »

Edit: This post was wrong so I removed it, thanks KTuner.
Last edited by Audiophyle on Sat Jun 25, 2022 7:20 pm, edited 1 time in total.
Post Reply

Return to “03-06 Element Specific”