2013 LSA fuel pressure drop at higher rpm

[Vicster]

Hello,

2013 ZL1 LSA modified engine with over 1,000hp.
Livernois dual fuel pumps.
I use the Beta software.

My fuel pressure drop with higher rpm's, I am sure it is due to the fuel pumps not being able to keep up with engine demands. Still a lot of room for the injector duty cycle.

I have searched the forums for the info I need but just ended up confusing myself. I am including the log from the dyno run. I have just installed a 3rd fuel pump with a 5psi hobbs switch. So I do not know if the 3rd pump will correct this issue yet. I read in other posts that with a boost pump installed that the FPCM = Mode Conditions = [ECM] 17022 - High Flow Upper, [ECM] 17023 - High Flow Lower, [ECM] 17020 - Low Flow Upper and [ECM] 17021 - Low Flow Lower need to be adjusted.
Some of what I read said to adjust them higher and some say lower...

Any advice and help would be greatly appreciated. Please ask if you require more information.

Thank You, Victor

[hjtrbo]

Run a log again with fuel pressure sensor volts. That will tell us what's really going on. The fuel pressure we log is calculated and as best we can tell is a modelled value.

[Alvin]

Hello,

2013 ZL1 LSA modified engine with over 1,000hp.
Livernois dual fuel pumps.
I use the Beta software.

My fuel pressure drop with higher rpm's, I am sure it is due to the fuel pumps not being able to keep up with engine demands. Still a lot of room for the injector duty cycle.

I have searched the forums for the info I need but just ended up confusing myself. I am including the log from the dyno run. I have just installed a 3rd fuel pump with a 5psi hobbs switch. So I do not know if the 3rd pump will correct this issue yet. I read in other posts that with a boost pump installed that the FPCM = Mode Conditions = [ECM] 17022 - High Flow Upper, [ECM] 17023 - High Flow Lower, [ECM] 17020 - Low Flow Upper and [ECM] 17021 - Low Flow Lower need to be adjusted.
Some of what I read said to adjust them higher and some say lower...

Any advice and help would be greatly appreciated. Please ask if you require more information.

Thank You, Victor

You shoudl log fuel pump short term and long term trims. I forgot the actual name. But be sure that the pump is being commanded 100% when you are dropping fuel pressure. If it is trimming itself down in part throttle because it has too much pump it can bleed over into pulling it down at wide open. Just how like fuel trims from part throttle an stick at wide open too.

[Vicster]

Run a log again with fuel pressure sensor volts. That will tell us what's really going on. The fuel pressure we log is calculated and as best we can tell is a modelled value.

Hello,

Set up a channel for fuel pressure sensor volts and a few others. Will post log as soon as I can car is on the rack right now with the rear tires off and I have to fix the OEM (Livernois) fuel pump output fitting.

[Vicster]

You should log fuel pump short term and long term trims. I forgot the actual name. But be sure that the pump is being commanded 100% when you are dropping fuel pressure. If it is trimming itself down in part throttle because it has too much pump it can bleed over into pulling it down at wide open. Just how like fuel trims from part throttle an stick at wide open too.

Hello,

Set up a channel for fuel pump short term and long term trims. Will post log as soon as I can, Thank You. You got the names correct.

[Vicster]

Hello,

Here are 2 logs since I got the car back on the road.
I have run into another issue, I hope someone can help with. Since putting my fuel pumps back into the fuel tank the fuel pumps do not spin up to pressurize the fuel system at startup anymore. I do have a fuel pressure gauge on the fuel injector mainifold.

Thanks for your time and help!

[hjtrbo]

Fuel pressure looks alright. Be nice to see a full pull.