7875 + 5.9 + E85 + Megasquirt
Got a response from SnakeEater. Their only suggestion is that maybe I don’t have enough fuel delivery to satisfy these thirsty injectors. OK. But even at idle they run hyper lean?
So I decided to just tune them. Reset my required fuel, dead time, etc to match the 142lbs, added a bunch of fuel to the VE table to get it to idle, added 20% across the entire table to get it going, still too lean off idle. Add 20% more. Now we’re closer. Enabled the AFR short circuit so that it cuts spark if we go too lean while in boost. I get into low boost, it’s still lean, add some fuel to VE table, hit it again and we’re rich. Come home, pour over the logs. Although it’s really rich and I know I need to pull some fuel from the VE table what gets me is that the duty cycle is essentially the same as my old injectors with all other variables being igual; TPS, RPM, LOAD, AFR, FP, etc. it’s like 40% duty cycle at 6psi which was the same as my old 80lbs.
:wtf:
Here goes something I have zero personal experience with but I just saw a video about something similar to this so take this for what it’s worth which is damn near nothing.
Last week there was a 2 day webinar called Engine Performance Expo. It covered all manner of topics, but they built a Pro Charged LS and Ben Strader of EFI University did most of engine specs and the dyno tuning.
I can’t remember the exact RPM they were going to turn the engine but it was at least 8k. Not that that matters much, but it’s part of the story.
Anyway, they broke the engine in NA and then installed the PC. They started making pulls and about 7k and up it started looking lean. So he added more fuel. It was still lean. And then more fuel. Still lean. More fuel. And still lean.
I also can’t remember how much more fuel he had added but it was a big number...like 120% more fuel and it was still lean.
So he decided to stop and really look at the data. What he found was the fuel system in his dyno room wasn’t capable of feeding the injectors so even though he was “adding” more fuel it really wasn’t because the pump couldn’t keep up with the demands of the injectors.
So there may be something to what Snakebite is claiming. I don’t have nearly enough experience with EFI to give even a little advice, but I thought it was interesting what I saw last week and it appears to mirror your situation. Or not!!! I just don’t know but it sure seems similar.
I don’t think the Expo from last week has been published to YouTube yet, but if you go to engineperformanceexpo.com you should find a link that will hook you up with both days of it. There should be separate links to all the various segments they did, or you can open up the entire 8 hour or so long link and scroll through until you see the engine the dyno and watch from there.
There’s some really good info on webinars like this.
I hope this may help you sort this out. You could even call Ben at EFI University and pick his brain to make sure I’m not nuts and wasting your time.
