Transient fuel causing lean spike?

[Tferrellsn95]

Hello Everyone.

I have a 2008 G8 with a 408 LS and FI billet 88mm T4 turbo. E38 PCM using 2 bar SD. TH400

I have been fighting a lean spike upon acceleration for a few days now. I suspected the issue was related to Transient fuel but nothing seems to improve the spike.

My question for you guys is what does the PCM reference for impact factor gain when using a Speed density OS and no MAF? The MAF is obviously long gone on this vehicle so the scanner always shows 0HZ as you would expect. I will include a copy of my current tune and log but you can see the huge bump in my VE table trying to combat this. See the 11:45:57 area for the most dramatic instance.

Any help is greatly appreciated








G8 turbo (changes).hpt
log 5.11.21.hpl

[Mr.z0611]

What type of injectors and fuel system?

[Tferrellsn95]

It's a Squash dual pump system feeding FIC 1200s

[Mr.z0611]

Which scaling method did you use to scale the flow rate?

[Tferrellsn95]

I used the ERM scale calculators