Measured AFR way richer than Commanded - 33% E85/91 Versatuner Tune

AeonPsych

AeonPsych

Greenie N00B Member
Greenie Member
Hello,
Running a self-tuned base map with a 33% E85 and 91 premium mix. I have advanced ignition timing 4* so far over a couple logs, and no KR logged under any condition. I used an e85 calculator to change fuel gravity for my mix, and have increased fueling tables up to my max rich power calculation (which happens to be 0.8051) and interpolated between max and low load tables.
Under WOT normal, I have max rich set to .802 at 4500 rpm, and under overload/knock I have set to .7823 same rpm.

Watching the real time logs on my dash for torque pro app, I see my idle and cruising AFR measured around .986, when I have it supposed to target 1.034.
Under load, it measures as rich as 0.6136 transitioning from about 1.00 load to 1.3 load (4-5k rpms) and -5 psi to up to 10psi, to where it will finally lean out to around 0.8142 at 5k rpms, which is a lot closer to my expected target.

relevant mods: HPFP, stock DP/turbo/intake, with 3" straight cat back exhaust.

Basically, I'm wondering what would be affecting the car to run slightly rich under idle/cruising, and up to .1687 more rich than the richest I have any table set to for that specific area, and up to .1884 more rich than I am expecting.

For those that don't read lambda, I'm targeting roughly 11.8 AFR, when it's measuring roughly 9.1, and I'm trying to figure out why, or what I might be missing in the tune.
 
Which tuning solution are you running? If it's Versatune, do *NOT* change the AFR targets; leave them as normal pump gas targets (yes, even on full e85). Also if genwon, you cannot command to idle at anything other than lambda, so you'll have to adjust for cruise instead (see my attached targets) like I do specifically to work around this issue.
 

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I didn't adjust MAF at all, I'm assuming since it's stock, I wouldn't need to.

Tuning versatuner on 2008.5, so yes, a genwon.

So don't change any of the targets to the newly calculated max rich? I think the new calculation is actually leaner than previous, so kind of odd if so
 
Correct, the calculator that's built in accounts for the scalar and density that the AP uses. I do the same for full e85, and still target .8 lambda (or something like that) for WOT.
 
ok, so if I have it right, I originally used the versatuner calculator to calculate 33% e85 which gives 0.785 specific gravity, 12.819 stoich, and 0.661 adjusted specific gravity. I went into the "Fuel Specific Gravity" table and changed it from .74 (stock value) to .661 (33% calculated value). I change nothing else for fueling? What if I want to lean out the mix from stock a little bit, is that not possible then?


The other tables I changed were:
AFR Target UNK
Closed Loop AFR Target Extended
Cold Crank after start enrich
and the handful of open loop WOT/Part throttles
 
From my current tune:

FSR.PNG

WOT AFR.PNG

And you already have my closed loop table.

Again, you cannot lean it out at idle, it will throw codes if you try. Best you can do is what I've done and set up a lean burn for cruise.
 
ok, but what about under some load like .8-1.4, where it seems to want to spike to like 9.3:1, roughly 0.6136 ?
 
Well you have my fuel tables up to 1.5 load, which is my hard transition into open loop.
Reset your fuel tables to stock; leave the scalar for your current mix as it should be and do a quick test. If it's pretty much on target, then you're good to adjust from there. If not, calibrate the MAF.
 
Enki said:
so you'll have to adjust for cruise instead (see my attached targets) like I do specifically to work around this issue.
Click to expand...

If you want to command AFRs leaner than 1Lambda you will have to disconnect the secondary O2 sensor. And of course disable DCTs for the secondary O2.
 
That must be the other part I knew I was forgetting. I've not had a secondary O2 for years.
lol
 
oh, so maybe that is my issue? The secondary o2 is overcompensating for the tune running lean?

Do you know off the top of your head(s) the codes to disable that specific o2? In versatuner, all it lists are a bunch of Ho2S heater control circuits. I'm guessing since it has an S at the end it is referring as secondary, but I don't see any other o2 identifiers to disable. I'm assuming they don't even have the option to disable the primary, but just want to make sure before I go and accidentally destroy something lol.

Would removing the o2 allow commanding of leaner idle too, or would that still not work like enki is suggesting?
 
Again, you can't command a leaner idle. You can try, but it won't go well for you.

Just unplug the secondary O2 and disable the codes that come up.
 
adjusted the tune fuel tables back to stock, left the fuel specific gravity to the calculation I supplied for e85, and then set the cruise area you posted.
Idle tries to command 14.3ish still according to torque pro, and can sometimes get 15+ while cruising, but it jumps back and forth between that and like 14.7ish.

Most I seen it under load was 10.5, so still a bit richer than what should be commanded (11.5 I think is the richest I have any part of the fueling. If not, 11.00 is for sure the richest, but only under protection tables)

Haven't removed the o2 sensor. I don't have a working jack right now to get to it, and I'm not going to try and use the OEM jack for this lol. I'm thinking maybe the secondary o2 delete might help. I know my cat is likely destroyed anyways. I have had a lot of crackling and popping during shifts and occasionally during decell , even before tuning , and I'm sure that's not healthy for cat or secondary o2 readings. Not sure how I haven't thrown a code for something related by now.

Also, I might have a vac leak somewhere now. My LTFT were around -8%, but I've noticed it getting worse after switching over to e85, where it's creeping up to -14% now. When it was -8%, I didn't pay much attention to it, as my logs were showing close measured AFRs to Commanded, and what I put in the tune, and MAF logs seemed to check out as well... Now, not so certain, which I guess could also be the reason for over rich AFR readings.
 
It's the same leak but on E85 it needs more fuel per given measure of air, so, well, there you have it.

As for the secondary O2 sensor, no need to lift the car, just pull the intake and inlet to the turbo and it should be right on the top rear of the transmission, right there. I forget which one it is but it should be pretty easy to identify; just unplug it and ziptie it out of the way for now.

For the rest, I'd consider a boost leak test then MAFCAL for the rest.
 
Re-upped the tune with stock idle fuel values. Logged a long ass cruise with moderate 1st gear pulls on them... Seems like the measured AFR likes to spike to the low 9s when I give around 30-50% (possibly more) throttle from idle or low rpms in 1st gear, as it switches over to open loop maps. I checked in my maps and the values in the log still don't even command less than 11.00 AFR, so not sure why the spike way rich, unless it's big boost leak, but from what I remember (I didn't log any this time), it will snap back to what I command shortly after the spike, and I'm able to hit boost targets as well, so not sure if there really is a leak or not. Definitely planning to do a full leak check at some point soon.

I've posted a screen of the log I am referring to. begins braking to idle, idle for a bit, and then a 40%ish 1st gear pull where it will spike up to 9.52 even when it is still commanding 14+. I'm assuming it transitioned to open loop right in that area as my fuel trims snap to 0. Also right where I begin building boost according to the log.

Still looking to disable the secondary o2, just not about working in the heat, rain and/or mud. I have no garage or carport lol.

Also, idle seems to want to command mid to low 14s, which I am kind of sad about especially since I'm running more expensive fuel now. Don't remember what it was commanding before, but I could have sworn it was higher 14s
Log.png
 
disconnected the secondary o2 sensor, and disabled 2 codes that popped up for it. Still wants to run super rich seemingly during transition to WOT, have not confirmed this specifically yet. It's almost like their is a throttle tip in fuel table that it's running off of.

Other than that, it seems to be commanding and measuring leaner cruise now
 
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