GroupA242

Edit: See post #32 for the conclusion. TLDR: it was just a setting in the iDash that needed to be changed.

Hopefully, the title has grabbed some of your attention lol. A little context:

I bought the car back in November of '22. It has some modes to it: MPx turbo back cat-less 3" exhaust, ZZP short shifter, ZZP upgraded intake elbow (to replace the factory plastic that always cracks at the PCV hook up), and the Injen hot side IC pipes. I have reason to believe it at one time also had the MPx IC and a Hahn CAI, but suffered a small yet big enough accident to break those, and now the factory IC is back on. I think that detail matters because the car also has a switchable tune, activated with the cruise control button. I assume the tune was optimized for the intake, IC, and exhaust combination.

Fast forward to now, and I just got the Banks Power iDash Super Gauge and a dual gauge pod from ZZP. It's really nice so far, kinda like an aftermarket RPD. Now that I've worked through the normal boost leaks and other basic stuff the car runs good and pulls hard.

However, now that I can see many of the PCMs measured values I am confused. Idle, cruise, and part throttle it holds around 14.7 AFR, but the first time I did WOT and watched the gauge it climbed all the way to the high 17's before I let off. Now after a few days, I have realized the car must have been doing this all along, because I have not changed the tune, and if anything the work I have done puts the car closer to stock. On the iDash I have 8 things showing at once, and these are what I have observed at WOT so far.
- AFR goes to 17.5 - 18.0
- AFR Command goes there too 17.5 - 18.0, the actual is always within a few tenths of the target (if I do the same with the tune off, boost is 15-17psi and AFRs stop around 16)
- Ignition timing ends up around +10 - 15*
- Fuel Presser is up around 22-2300 PSI. (could be more than this? I wasn't really paying attention to this number, but it definitely increased into the 2k range)
- When let off and coasting in gear in the DFCO rpm range the AFR goes all the way down to the 7s??? I though it cut fuel for coasting?

All of these values behave steadily. That is to say, I know there is some latency in the readout on the gauge but they are not jumping around wildly. And the car runs strong?! I do not hear any knock (not that the KR would let me hear it anyways), it doesn't hesitate or skip a beat.

Anyone got any ideas what's going on????

GroupA242

Also, a little internal combustion fuel mixture theory:

A stoichiometric mixture is the point at which all 'ingredients' are consumed completely in a reaction. In the case of our glorious gas-powered engines that is 14.7 parts of air to 1 part of fuel (14.7:1 A-F-R). This point of total consumption (or combustion in our case) also means the highest heat produced as EVERYTHING is burned.
- If you 'richen' the mixture, there is excess fuel left over and the temperature is lower (peak power is found on the rich side of stoich. The idea being you are leaving no air molecule left unburned)
- If you 'lean' the mixture, there is excess air left over and the temperature is also lower (any mixture of gasoline and air less than stoich will have less power potential because you could not burn all of the air).

Said another way, you can produce the same EGT (exhaust gas temperature) at TWO different fuel flows. One producing a mixture richer than stoich and another producing a mixture leaner than stoich (all other variables being equal).

And finally, the temperature change is much steeper on the lean side of stoich.
A rough example: 13.7 AFR= 1500*F 14.7 AFR= 1600*F 15.7 AFR= 1425*F (you see how one point leaner is cooler than one point richer from 14.7)

AfterShok

Have you done leak down / compression?

Do you know who tuned it ? (Trifecta by the sounds of it if you can toggle with cruise control)

I doubt the tune is leaned out that much so I would think towards something being wrong. What are the fuel trims?

Fuel rail pressure will raise to 2k+ doing WOT so that's perfectly fine.

fst100

any trouble codes on by chance?

GroupA242

I have done a compression test, just a few days ago (it didn't thrill me): 1/115, 2/155, 3/155, 4/120. The engine doesn't use any coolant. I added a few drops of oil to cylinders 1 and 4 to see if it came up (would indicate worn rings) but they changed less than 5 points. I'm guessing they could be low due to leakage at the valve? Though the number didn't drop in the 60 or so seconds it took me to get back to the engine, look, write it down, and then finally press the little relief button. I don't have the hardware for a leak down at this very moment.

I do not KNOW who tuned, it, though I know for sure the car was once tuned by Trifecta. Since it is a 4 door, it's on the SSsedan registry page with a list of mods. One of them was an "OTS Trifecta 23 PSI tune" whatever that means. So I think it is still that tune.

I also don't think it was done intentionally but the Target AFR and Actual AFR stay very close to each other (I am assuming the the "Commanded AFR" is what the PCM wants to see the AFR at). I am not remembering specific fuel trims ATM. I was showing both LTFT and STFT at the same time but the LTFT didn't ever change much so I swapped that out for Catalyst Temps (EGT I believe) and just kept the STFT to watch. I don't usually see big numbers on STFT unless its right after a throttle chop or blip (or maybe on startup) and then they quickly go back to 0 +/- 5 or 6. I will drive it later tonight and do some more observing/logging.

GroupA242

Most recently I have been having a p2188- system rich at idle. I think this was due to me having just cleaned (and probably over-oiling) and then installed the K&N filter. So I then swapped back to a paper filter and cleaned the MAF and have not had the code again, though it has only been two days so maybe the filter and code were not related. But, I did observe some weeeeiiiiird fuel trims when it was acting up last time for the p2188 code and it was clearly very rich for some reason. So much so that I stopped halfway home and cleared the code to continue on (on Saturday). The next day I swapped the air filter back to paper (on Sunday).

I also just got a p2176- throttle idle position not learned, but that popped up right after I did the compression test which involved much cranking with the throttle floored and then shutting the key off over and over and over and over. I cleared that on Sunday afternoon and it has not come back in about 100 miles of driving and maybe a dozen on/off cycles.

fst100

yikes at cyl 1 and 4. i ran across the below "ranking" for what's considered acceptable and not acceptable in compression drop:
Under 5% - awesome
Under 10% - good
Under 15% - acceptable
Over 20% - bad news for your bank account

GroupA242

Yeah, I know it’s about a 27% drop from 3&4 to 1&2. I didn’t exactly did the test when the engine was still hot. I had been probably more than 2 hours of sitting. So maaaayyyybe those being the outside cylinders had cooled enough to loose those points?

But then, it’s not the HG (never uses coolant and no mayonnaise oil). It didn’t leak down so valves are sealing (though I could wait longer next time and really watch). Do I just have two missing pieces on 1&4 or bent con rods but then how does the car run pretty perfect otherwise?

I will recheck this afternoon after I get home, right after a shutdown in the garage.

After more driving last night I observed consistently at WOT:
- AFR commanded reaching 17.0 above 5500
- AFR reaching 17.0 above 5500 (always within 2 or 3 tenths of commanded)
- STFT stayed at between 0 and +2 during accel
- LTFT stayed between 0 and -2
-Ignition timing retarded to +10 and stayed steady
- Fuel system stayed in Closed Loop
- MAF was reading 25+ and increasing all the way to shift

Coolant temps would stay in the 190s and immediately cool back into the 180s when not flooring it.

I did all this with the tune off so there was more time to read stuff. The effects are the same with tune on, but it’s goes faster haha.

fst100

so with the aftermarket tune off, where does it boost to and hold and with the aftermarket tune on, where does it boost to and hold? do you have any other means of scanning besides the iDash?

GroupA242

Tune Off: 15 PSI then ramps up to 17 PSI at higher rpms

Tune On: 20 PSI then ramps up to 23-24 at higher rpms

No other means besides the iDash right now. I have decided I want to remote tune via ZZP since they can supply all of the items needed. But I wanted to wait until after I had purchased at least the IC kit since a factory one is installed right now and I know that's only a matter of time before it will fail. They also say "we don't tune around problems" haha though I think this could be slightly different.

Seriously, If I had never hooked up the iDash I would not have worried at all because there is no indication anything is wrong. I guess this could be an indication problem, but then why to the target and observed AFRs stay so close, and show reasonable levels otherwise?

Does anyone have data on what their ignition timing advance/retard is at WOT? That could give me something to compare to since I cannot find KR in the iDash.

fst100

im surprised the iDash doesnt provide knock retard as a PID to scan. knowing if you're getting KR when going WOT and especially if the AFR is showing lean is important. thats how you get chipped pistons. is your car a manual or auto? if you know anyone local that has hptuners or maybe invest in one may be beneficial.

GroupA242

It is a manual, F35 (ya know, it's an SS thang). Yeah, I am surprised by the lack of a KR read out too. Maybe it's because Banks deals a lot with diesel stuff where that is completely irrelevant hah.

Yes, I am looking around now for someone in the SA to Austin Texas area.

fst100

yea i keep forgetting about the cobalt ss being only in manual, i have a hhr which comes in either auto or manual but still shares the LNF motor. if you have a bluetooth obd2 dongle, can download the torque pro app for $10 which actually scans KR. i dont know if the torque app lite trial version has it available or not.

GroupA242

Crazy idea: I realized after watching the AFRs for long enough that they behave almost exactly backwards.

Everything stays around 14.7 but instead of any power enrichment it's as if it is "power leaning." If it went in the other direction under load it would be in the high 11s or low 12s.

14.7 to 18.0 = 3.3 points difference. 3.3 points difference in the other directions would be 14.7 - 3.3 = 11.4. Maybe even too rich for WOT but reasonable instead of what I am seeing now.

Even when coasting in the DFCO range it says AFR 7.3?? Shouldn't it go super lean since it is essentially in fuel cut off? Could this actually be an indication problem somehow showing the AFRs backwards?

I did go ahead and order the remote tuning suite from ZZP (HPT interface and laptop) so hopefully that is here by mid-week and then I'll have some real data logging abilities and get an updated file to flash onboard regardless. I will let update with what I find.

fst100

thats possible and if so, maybe the setup is incorrect or defective iDash software? did it come with any instructions for troubleshooting? usually when you let off the gas, say at freeway speeds, the DFCO ought to be lean and show somewhere like 18.0:1

AfterShok

Waste of money! Invest in HPTuners which will be slightly more BUT you get to keep the interface for future logging AND if you decide on changing tunes with a new tuner.


Also OTS means off the shelf so it was a quick flash by Trifecta which don't have the best reputation. Also there are claims that trifecta tunes = bricked pcm for tuning as they lock it. So if that's the case you might need to source a new one.

GroupA242

I did order the HPTuners interface and laptop from ZZP. I have the option to keep both things if I want to, or I can send them back and get reimbursed (if you send everything back then the only cost out of pocket was about $310 for a whole 14 days of remote tuning. I think that is a pretty good deal).

Thank you for clarifying what OTS means.

As far as Trifecta and the "bricking" of PCMs -> I told ZZP my situation and asked if they could just email me a stock file to flash right away and start from that, and they said: "... We will have to wait and see when you get the HP Tuners, sometimes you can write over trifecta files and sometimes you can't. When you get the HP Tuners see if you can read the file or not and we can go from there."

I also read and have been told by other forum members that you can simply write over a Trifecta tune when needed. But you cannot specifically edit the tune itself unless you have the Trifecta hardware or it is done by them. So..... we'll see.

fst100

once you get the hptuners and laptop, like what ZZP suggested, do a read file first and save a copy and name it something. that way you have a starting point. any changes/flashes afterwards, just save as a new file name and not overwrite the existing one, if that makes sense. yes i also heard that some trifecta files cannot be overwritten as the company actually decodes and make changes in the OS unlike how hptuners can just edit the tables only. thats how trifecta is able to do the switchable tunes on the fly with the cruise control button for example.

GroupA242

Yup. I have watched their instructional video several times and I have it loaded in another window to watch again once everything shows up today. UPS says it is out for delivery

In a correspondence from months ago, ZZP actually told me they had switchable tunes that were not from Trifecta. It was unclear if it was from ZZP directly or if that worker was just referencing some other tune they had/made that was switchable. I'm happy to not have that anymore as I understand that has negative side effects in the long term (See this post #27 from a nearby thread). There is SO much info floating around about stuff like that and often it contradicts. I will, at least, be able to put this to rest in my case this once. Hopefully, by the end of this, I can have a good summary of all my findings so this thread is useful for someone else later on.

fst100

one thing to note is the e69 pcm is an older OS, meaning that unlike other model years, in hptuners they dont have the ability to set any DTCs to no reporting. what that means is even after doing all of the GM driving relearn cycle, any DTCs that are turned off will show in the mechanics's computer as "Not Ready" and automatically fail. i dont know if otthers got around this or not, but my only method is every year when i take my car in for inspection in PA, i would have to reflash back to my stock tune and complete the necessary drive cycle and then pass all of the emissions/diagnostics.

GroupA242

I'm not in an emissions county here in Texas so as long as the CEL is not illuminated (and everything else is working) it will pass. So I would like to see them optimize for power, reliability, and then efficiency, and really nothing specifically for emissions. (I don't think emissions = efficiency in most cases. But if you can make something as efficient as possible good "emissions" will follow).

It will be interesting to see what they say/do though. I am having a hard time finding threads and posts about tuning that are less than 10 years old (I guess I just need to start reading all the threads backward). So surely some things have changed in the last decade as far as what has been "unlocked."

GroupA242

I just got the laptop/HPT interface from ZZP.

Got it all plugged in, turned the key to on, and after using the "Gather Info" button, then selecting "Read" it goes to an error message:

"Reader Upload Request: x7F Negative Response Code"

It did correctly identify the VIN and the hardware as E69 ECM, and an Operating System 12629314.

Is that what it looks like when being shutdown by trifecta?

fst100

that i dont know, but aside from waiting on what others would say, did you take a screenshot and sent it to ZZP to review?

edit found this on hptuners site using google search:
Reader Upload Request :x7F Negative Response Code Error – HP Tuners
try this thread out as well
Reader Upload Request: x7F Negative response code error ???????? (hptuners.com)

also see post #27
New to me LNF - I think it's tuned. how to tell? - Page 2 - Cobalt SS Network

GroupA242

I did send ZZP a message. I couldn’t send a screenshot because I cannot get their laptop to connect to my internet?? Haha that’s annoying. It is an old dell, poor things runs like azzzzzz. And I only have a MacBook otherwise.

HPTuners support pages is pretty hard to navigate, but a google search lead me to one of their support articles (go figure). It said:

“If you receive the Reader upload request :x7F negative response code error, this likely indicates your vehicle has been previously tuned and the ability to read the tune has been disabled.”

So I’m waiting on ZZPs reply to this news. I think my options will be as follows:

1. They can send a base file and just “write entire” to hopefully get rid of the this
2. Maybe I’ll have to get the dealer to flash it back to stock
3. Absolute worst case a new PCM is needed

GroupA242

lol, edited as I was typing my reply. Yep. I had seen that. And good catch on post #27.

I had contacted trifecta months ago when I first got the car and they said it was not in their system (the VIN) as ever having been tuned so I don’t think asking them for anything will
help.

looking like options 1 or 2 are my best bet. All I can do is wait on ZZPs reply now.