You are tuning the high octane table and do not want it to default to the low octane table

On ethanol cars that we race i leave them the same most of the time

 

When I'm finished tuning a car I generally do a -5 blanket on the HO table and copy it over, with even more pulled wot. If it's kicking over to LO for some reason, I want the driver to feel it and know in case they're not paying attention to (or haven't noticed) other gauges/warnings/etc.

 

That makes a ton of sense. Thanks guys.

I copied in a better timing table last night. (Both tables for now) thanks jp1600

The car is WAY better. Surges a fair bit at low throttle angle in first gear.

I need to figure out what else is just WRONG with my base tune, and I need to study up on building a proper config, pids, sensors, and configuring histos properly.

Study, study, study

 

Yeah gotta get that throttle body dialed in

 

color me amused.

gm flex fuel vehicles will never hit 9.85 stoich on pump ethanol. i know this for a fact.

the reason behind the 10.368 stoich is that you put ethanol in the car as an "advertised" 85% content, you will not see 85% even with the cute testers people use. throw them away. you're looking at a sticker. you want hard fact, get an ethanol content sensor. you will not see 85% out of the pump.

the 10.3 stoich adds an error cushion in there for trim control and variations in blends at the pump. you fill up once in the morning and go back 2 hours later, the trims will change. over fueling is just as big of a killer of engines and running too lean.

 

^my hero

 

I know how much you love the tube testers but unfortunately, and I'm not advocating them as the end all for alcohol testing but, people who are much smarter than you and I use test tubes such as this in a lab with similar techniques to test alcohol levels, so it seems like it would be a relatively legit process. Also the Delphi report released a few years back examining fuel characteristic in GM DI engines, even tested pump grade e85 and rated it's stoich as 9.61. Even if the test tube was say +/-2% off, it's still quite a bit closer than throwing caution to the wind and guessing.

Another thing I'm considering here is maf skew. When comparing apples to apples using a stock air box, I saw hardly any maf skew when using a 9.83 stoich tuning for e85, which I of course verified with my crappy ethanol test tube.

Please keep in mind that I'm not trying to start a fight here, but there's also nothing wrong with a healthy and mature debate. If I learn something from it then great, but please don't be condescending just because I question a post you make.

 

in 100% box stock trim my 10 silverado never hit 9.85 on the stoich on the commanded afr. all of the other flex fuel vehicles i have tuned as well never hit more than 75% here. This is in the dead of summer as well so it wasn't a "mix". Unless you're getting it out of drum, you're not getting a perfect e85 mix. Use a content sensor, or calculate error in the maf scaling and run with it.

another fun side effect of of the 10.3 stoich is slightly more head room on the injectors.

 

with the coarse control on the P12 pcms there isnt much in the way of improving trims with big injectors other than scaling the MAF.

+/- a few percent is about as good as it gets most of the time. on LSJs you need to leave them a little loose on fueling to get the thing to idle and respond well

 

i got mine to hold 14.7 "afr" at idle and not move through the maf. moving it would jump from 14.4-14.9.

 

He had mine the same on a m62 as well

 

Doesn't help 90% of cars are using the wrong offsets.

 

well you cant fix stupid

 

With major help, my car has come a very long way in a short time.
I'm picking it up a bit at a time too

Now my issue is an inop IC pump. My IAT2's are ridiculous. I'll fix that and then get back to the tuning stuff.

EDIT; IC pump is working, but no flow out of the intake, so I believe the laminovas are in the manifold backwards. One more flow test to verify.
Not looking forward to tearing it all back apart, but it goes pretty quickly.

 

does you guys disable the MAF in order to run full e85 in LSJ? I have a problem getting the car started yestederday cuz my MAF was bad .. I order a new MAF

 

nope. I default the maf to primary air flow source.

 

as does..... everyone?

 

wow !
just saw this thread was back from the dead!

to update -- my car is WAY better now. I had BAD injector data, unfortunately from multiple sources. Once I finally got decent injector data the rest started coming along rapidly.

I still need to pull some fuel at WOT, just haven't had the time.

for anybody jumping in first time, like I have.......PERSISTANCE is key ! STUDY and READ your ass off, and just keep swimming....

 

Tuning tool, in addition... Start with the injector tables. Once those are correct, the rest will follow

 

I did an E85 conversion and setup ID1000's on a turbo LSJ, it's really not as bad as people make it out to be. If you know what the numbers mean and have some decent histograms set up (they are widely available if you don't wanna make them yourself), it's actually pretty easy.

VE tuning is a waste on this platform in my experience, you need a MAF to make the car drive nice and if you have a MAF it will be doing all the work anyway. Scale it to your piping and let the error % do the rest.

 

exactly right

if you don't -- you will drive yourself insane trying to tune around the bad injector data -- this is EXACTLY what I went through, and it was maddening.