So I filled my tank all the way up with e85 when my light came on just to try it out. The next day I couldn't get my pickup to start. Autostart wouldn't start it but if I turned the key and tapped the throttle when it popped off it would fire up, surge a few minutes then run completely fine. Runs amazing down the road. I sent some data logs of it trying to start, slow driving and a WOT to Justin. He said the logs looked really good.
i think he is trying to tweak a few things but in the mean time I want to check to see if there is something wrong on my part. I don't have any vacuum leaks, plugs and wires are good, and fuel pressure is okay. Not sure if my specs are included in mobile so here they are:
2009 Chevy 1500 5.3l flex 6l80
Tap 220r high lift cam, pac springs, new lifters for AFM delete. Tsp 1 3/4" long tubes with catless ypipe, rear O2 sensors tuned out and a custom BBP tune by Justin.
One thing I have noticed was even with 91 octane fuel I would random start ups where it would die out right when it fired off then cranked for a few seconds before firing again.

Any ideas are greatly appreciated

 

Unless you installed a flex fuel sensor the truck uses a virtual flex fuel sensor that is based off of what the O2 sensors read out. It's very possible that your trucks "virtual flex fuel" sensor is reading the incorrect amount of alcohol content in the fuel, thus leading to starting problems.

Like if you ran 91/93 forever before you did this, it's likely show less than 10% just about all the time. Then you go and dump 20-23 gallons of E85 in there which at this time of year is really like E50 to E60, it's likely to be off in most cases. If you can, data log the alcohol content and see if it's reading around 50-65% and if it's still showing like 10-20% or something way lower than what is really in the tank it can be an issue.

 

I will log in a bit a see. I was also thinking my virtual sensor could be messed up beings i am only running upstream o2's? Either way I will let you know I've what my alcohol reads. Maybe I will disconnect my battery, reconnect and reload the tune and see if that changes anything. Justin messaged me last night for a few more questions. Hopefully will be getting something back in a day or 2.

 

In order for the 'virtual' sensor to work, your base airflow calibrations have to be near perfect. Any persisting error in airflow calibration will get baked into the calculated ethanol percent because it must freeze fuel trims while learning ethanol content. As far as starts go, that's another task entirely. I'll wager you're probably lean on the start fuel

 

Snap on ethos tells me I am running about 72% alcohol. So my pickup knows what it's getting. I am sure I just need a little more start up fuel.

 

It thinks it knows what its getting..

 

dump that **** on for a cold start.

 

You're in ND and it's probable cold as ***** there. E85 does not like the cold... Probably needs more startup fuel. Personality, if it's really cold there, I wouldn't run it strait, 75/25-50/50 or somewhere along those lines.

You not gonna see much gain out of it being a normal compression NA 5.3 anyway. Just gonna get less MPG's. Only real advantage is if it's much cheaper than 93, Like 50 cents or cheaper per/gal.

 

I am getting e85 at a 1.36 a gallon compared to 2.75 for premium. I wanted to do a comparison to see if it was worth it. And once I finally get around to putting my turbo kit on I would like to run it as well. I don't know if it's just placebo but it does seem alot snappier than on premium.

 

you mite need to adj the choke in the PCM
for the E85. for start up.