Hi, I have a 2005 ctsv that I just did a cam on (227/235 110+3) and has a few other bolt-ons (headers, full exhaust, fast 102, 92tb, CAI) and I've been having issues where it's going pretty rich (as low as 0.7 lambda on the WB) on decel. I just put in bigger injectors because the stock ones were maxed out, replaced with DW65lb injectors, ls3 style with adapters. DW provided data which I pasted into the appropriate tables but it still seems to run very rich when I let off. The min injector PW is at 0.729 but it seems that when it's running too rich the logged PW doesn't go below 2.4ms on decel, although it does dip lower at other times. It seems like it's riding on some limit because the fuel trims are pulling more negative at those points but inj PW is a flat line. I am also a bit confused about the IFR data they provided because they are listed as 65lb injectors but the data they gave goes from 85-93 lb/h? I'm assuming I need to mess with the SPA table and maybe transient fueling? Could anyone give some pointers on how to start? Any help is appreciated. I'll post the tune, log and injector spreadsheet with this.
Edit: I found another datasheet for the injectors that shows they flow higher than 65lb because fuel pressure is 58psi

 

16U-XX-0700-X_Injector_Characterization_Summary.pdf (shopify.com)

 

You are correct on the flow rate being different, base on the base fuel pressure. I haven't looked at your tune, but is DFCO enabled? If you're not sure what that is, it's decel fuel cut off.
Based on what you have said, it should be cutting it down lower though. Have you logged the map reading to make sure it is reading correctly?

 

Yeah I have DFCO turned off while I'm working on getting the VE and MAF dialed. I could turn it on, but that seems like it would be masking the actual issue, since I was able to be stoich in the decel areas with the stock injectors, but not the new ones. I also zeroed out the transient fuel min mg number although that didn't help. It looks like there is some sort of injector pulsewidth floor that is causing it to not drop below 2.4ms, although I just can't figure out what table that would be since the min PW table is at 0.729ms per DW data.
I'm not sure how I would verify my MAP data is correct, but it gives pretty consistent numbers in the chart and seems to make sense. KOEO MAP is 102kPa and I live at sea level so that checks out

 

Go into your injector settings and cut the min pulse width down 10 or 20% at a time up a few cells in the table until you see improvements. I’m away from my computer otherwise I’d actually look, but 5 or 6 cells over is where I typically do it.

Assuming you’re probably going back to enabling DFCO after tuning (for the crackles lol) but I could be wrong. It does help with MPG though and it’s cool to have a little crackle sometimes.

But yeah, to get rid of that you have to play with the injector boundaries.

 

Don't forget that the LSA injector has a bent spray angle to help aim at the back of the valve. When you put a new injector in with a straight cone, you are wetting the port wall a lot more. You'll probably need a big adjustment (~30%) to the Fuel To Wall Impact Factor (under transient fueling tab) to account for this.

**EDIT** I just noticed you have an older (2005) v, not the LSA Gen2. Regardless, your Impact factor table looks REALLY odd compared to what we normally see in an LSx. This may be a big factor in some of the behavior you're seeing. Try modeling it like a stock LS3 where impact factor decreases with temp rather than MAP and see what happens.

Then you can go back and check all the usual stuff like min PW, min transient fuel mass, and the accuracy of your VVE down low.

 

Thank you! I figured I wanted to get VE done first before transient but I will definitely work on that. Should I pull a stock LS3 or LSA file from the repository and use its impact factor table and trim it from there?
Edit: You mentioned decreasing with temp instead of MAP, but I did some research on transients and someone suggested that the table uses a percent change from row to row, is this just incorrect? Or do gen3 and gen4 do transient calculations differently?

 

You are correct that I'll be turning DFCO back on when I'm done tuning. So I figure I'll have to slowly lower the min PW until it's not rich there anymore. I did also see a drop in PW when I set the default PW table equal to the min PW table (now goes to 1.9ms) so I think this is the answer.