COS3 OLSD to SemiOLSD

I've had enough of fooling around with tunes every major season change. I always feel like I have it nailed just to be disappointed next year :lol:

I've installed o2 sensors and changed stoich to 1.0 where I had it at 1.01, and drove a little while logging STFTs and got zeros.

How do I test to see if these O2 sensors are functioning, or if something is amiss in my tune file?

After more than 5 years of screwing around with this I'm still not seeing consistency. I'm actually considering getting some kind of Holley setup or something else for a non-expert.

:help2:
Attachment 22528

Hi Jim,

Your B0101 VE table looks bad.

Are you getting any DTC's (other than for MAF failed)...?

How long have the NBO2 sensors been there...? Are they fouled...?

The narrow band sensors look fairly new. I haven't had them installed in years, I don't even remember where they came from.

I hunt and chase the VE every time. I think I have an untunable car. Seriously, I've been doing and re-doing the VE for 6 years.

No other DTC's. I have occasionally getting Limp mode when it gets hot outside, but it doesn't give any specific code for it. The longer I sit here and sip on my beer, the more I realize I either need a professional and $5000 cash to pay them, or I need to just get a Dominator and hope it can cure itself.

I've put over 80,000 miles on this car and have never found a place where the VE is just a little off in either direction across the board based on weather changes. I would get the VE in +/- .02 in all cells, re-log over the next few days when the weather was consistent and I'd get similar results, but as soon as the seasons changed the BEN will start going lean in one area, rich in another, and I'll still have a small area where everything is OK. It has become a vicious cycle.

Last fall, when the temperature was in the 60'ish +/- a few degrees, I believe I did my last large-scale VE tuning (it looked nice at that time!). At that point I locked it in and attempted to correlate the IAT/VE scaler as the weather turned colder, then back to full-on summer heat, only adjusting the IAT scaler since I knew I had a good VE tuning session. But alas, through a fall, winter and back to summer, I'm in a mess again. At some point I probably tried to do VE logging with the IAT/VE scaler turned on out of frustration or curiosity hence the messy main VE table.

I probably convinced myself that if I had the IAT/VE scaler nailed down as I thought I did, that I could possibly adjust VE throughout varying IAT temperatures.

Quote:

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Originally Posted by Jim_PA

I've installed o2 sensors and changed stoich to 1.0 where I had it at 1.01, and drove a little while logging STFTs and got zeros.

How do I test to see if these O2 sensors are functioning, or if something is amiss in my tune file?

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You need to allow closed loop to enable... see table {B4205}

Quote:

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Originally Posted by Jim_PA

The longer I sit here and sip on my beer, the more I realize I either need a professional and $5000 cash to pay them

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I wouldn't charge you that much. :laugh:

So I started doing something I've never done, which is wipe out the VE coolant temp charge blending and VE/IAT modifiers. I'm going to try to start at ground zero with the VE and all the modifiers and see if I can't get a tune out of this. I'm just not sure if I've missed a VE modifier somewhere along the way. My o2 sensor has started reading way off the charts, I'm thinking it's dead? It will seem to work for a little while then pegs out in the 30's or 40's and hang there for quite a while then start reading again.

Here's some light reading for you....

https://forum.hptuners.com/showthrea...IAT-Bias-table

Good point made by statesman in pointing to that thread on the HPT forum...

Quote:

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Originally Posted by Bluecat @ forum.hptuners.com

. . .
Main thing to remember is that if at a certain air flow the PCM is over correcting with the IAT (Gets richer when its cold, leaner when its warm), make the bias bigger. If the PCM is under correcting (Gets lean when its cold, and rich when its warm), make the bias number smaller. Don’t think of it as cold/warm or rich/lean because your always going to have to redial in the VE. Remember that since the ECT is pretty stable and constant on a warmed up engine, biasing towards ECT (1.00) will make the IAT less aggressive (Less IAT correction) and making the number smaller will increase the IAT’s authority and make IAT correction stronger.
. . .

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Good reading in there.... I think it's part of the problem that may never be resolved for me. The supercharger has an IAT inside the housing that is not consistent with outside air temps. Once it gets hot and you shut it down for any period of time then re-start, it will never get back down to where it was during your first 30 minutes of driving, with all other conditions being very similar. Then again, the VE before the supercharger was never close enough through varying conditions, so time will tell if there's anything I can do about it.