2009 C6 Z06 Flex Fuel PE Problem

[matthewstearman]

2009 C6 Z06 heads cam with DSX Tuning flex fuel kit, and 49.9 lb/hr L9H injectors. Car ran well on the dyno with 91 e10. Made 545 rwhp 450 rwtq on dyno dynamics hub dyno. When we switched to e85 (ended up being 65% after mixing with fuel in tank) it kept going lean at 4000 rpm. Logs show PE enabled and commanding .854 lambda EQ, but the wideband begins to ramp to 1.00 lambda right above 4000 rpm. Fuel pressure was good throughout all the dyno pulls. 2009 E38 operating system 12628988 only has EQ Ratio (Gas). HPTuners tech support says this operating system does not have EQ Ratio (Alcohol), however it is obvious in the datalogs that something is commanding the EQ ratio to 1.00 at what I suspect is 4096 rpm. I can find nothing in the editor that corresponds with this to correct it. I suspect there is either a setting or table I am skipping over, or there is a table in the operating system not accessible that needs tuned. After having this problem we emptied out the e85 and put 91 back in. This got it back to 18% ethanol, which we made another pull with and had no problem with the PE. Attached is the tune (which has some minor changes since the logs), and logs (2 with 65% ethanol and PE problem, and 1 with 18% ethanol and no problem). Has anyone else experienced this issue? 2009 Chevrolet Corvette Z06 7.0L Dyno Tune 4-27-2019.hptpull 9 18% 580 degrees.hplpull 7 e85.hplpull 6.hpl

[Ben Charles]

Sounds like you just ran out of fuel... on the early ECUs alcohol PE is just the same as Gas (both share same table)
So if running out and commanded is good, gotta be out

[SultanHassanMasTuning]

remove the RPM delay at 5000

[matthewstearman]

Thank you, I will try removing the RPM delay setting. I am 100% sure it is not running out of fuel. Pressure was good during all dyno pulls with a gauge connected to the fuel rails. Also the pulls on 91 octane reached 73% duty cycle with no problems, but when it went to 1.00 lambda on ethanol pulls, the duty cycle only reached 52%.

[Ben Charles]

If you are at 73% IDC and everything is correct and you change to high concentration of E85 duty cycle would be 100 is easy..

Something is off friend

Hope it’s not 1.0 on ethanol during PE

[Xjas]

Weird how the injector pulse width just flat lines at 12.8ms after peaking higher than that, are you sure you have the correct injector data?