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I have a cobalt that has a zzp cai on it and a magnaflow catback. At idle the afr jumps around from lower 14s to higher 15s is this normal for a stock tune? Also when you touch the pedal and raise rpm toAttachment 85740 around 1200 rpm it goes to mid 16s then goes back and holds around a 14.7 everywhere else. What would cause this is it something in the tune?
Stoich for pump gas is 14.68 roughly, a little less if your fuels have up to 10% alcohol content at the pumps. O2 sensors will bounce lean and rich of stoich because that is how they function, so seeing the wideband show 14-15's bouncing around is normal because it's just showing you in real time what the o2 sensors are doing.
Seems like you have a lean spot if the fueling bumps up into the 16's and then back down to stoich.
The afr will sway a little bit back and forth to keep it at stoich and If you raise the rpm up a little bit at idle I'd expect it to lean out a little bit. Do you have a p0171 dtc? or any dtcs for that matter? If you havent been tuned for your cai that will make you run lean also
I dont think that i have a p0171 but ill check to make sure tommorow i had some other codes for an o2 sensor ill have to look exactly what they are tommorow
this may sound stupid but i tried to raise the maf calibration for the cai but that didnt seem to do anything so i just set it back to stock Im really new to tuning
sounds like the lower MAP pressure are of the VE table from 1200 rpm up needs some work. seems like the values aren't big enough and when it hits those cells it goes lean until the STFT being in closed loop can bring the AFR back to stoich
just looked at your file and it appears to be a gm stage 2 stock file for a 06 and depending on how off your airflow models are you may have to add quite a bit to get the trims back in line - do you have a log?
for tuning each airflow model you need to put them in each of their modes - you cant tune maf with ve still enabled or vise versa it will give you incorrect readings ... maf or ve ... for maf only set dynamic airflow disable to 200 and re enable to 100 and tune the maf chart - for ve only set dynamic airflow disable to 8000 and re enable to 7900, copy ho spark to lo spark and set maf hz to 0 (engine diag/airflow) and set dtcs p0101-p0103 to mil on first error - then after you get the trims to be + or - 5% then you can run a blend tune of maf/ve or just maf or just ve (i run maf only) - you can only tune wot with a wideband o2
heres a 07 stage 2 file Attachment 85742
Thanks for the info. I fixed the tune to make sure it was just a stock gm tune, seemed to help. I checked the codes only ones are p0420 which is catalyst system below effeciency. I also got a log today after i put the stock tune on. Attachment 85752
well a p0420 means the cat is junk or if you have a high flow cat it may set that dtc also.
idle seems to be fairly inline but your part throttle is lean so put your car in which ever mode you choose - maf or ve - and fix the airflow model to get the trims in line and shoot for a -5% average ltft
when you get a wideband work on that pe afr. the gm pe enrichment table is not ideal and fixing it can net good gains because fattening it up can allow for more ignition advance in boost.
to properly tune with trims you can use system filtering. its not ideal because you can run defaulted in maf or sd mode and not have to blend but you should have histogram filter that includes the annotation [50121]=14.7. this will exclude any data from your histogram where the ecu ignores the O2 sensors for power enrichment phases.
Attachment 85759
im not sure which mode your last recording was set up to be but by comparing the maf and ve tables with full rpm range and removing any data that isnt when stoich is commanded you get results that look like this.
Attachment 85758
this tells me you likely have to work on this but the data also tells me its a waste of time trying to go at it little adjustments at a time. in your case i would copy the recorded data apply an ecu correction by "paste multiply by percent" (whole)
this should close the gap pretty fast and allow you to move onto those smaller adjustments without wasting time.
* iat spark modifier table -multiply by .40 and set the mult table to 1.00
Im really new to this but can i use that info and just copy it into the ve table of the stock tune or should i set it up as an open loop and the re do the log and the copy that info by percent into the ve table of that tune
It's a copy and paste percent deal.
Make sure you doing the adjustment for the correct device in the correct mode. Sd=ve table. Maf= mag enabled