COS3 OLSD to SemiOLSD

[Jim_PA]

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:
22528

[joecar]

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...?

[Jim_PA]

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.

[Jim_PA]

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.

[statesman]

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?

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

[statesman]

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

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

[Jim_PA]

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.

[statesman]

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

https://forum.hptuners.com/showthread.php?15225-ECT-IAT-Bias-table

[joecar]

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



. . .
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.
. . .

[Jim_PA]

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.

[Jim_PA]

For example, on Saturday when I wiped out the VE modifiers and attempted a logging session, I started at outside air temp of 37 degrees. After about 15 minutes, IAT maxed out at around 70 degrees. I pulled into the garage, read the data, made some changes and went back out to confirm. On my 2nd trip, IAT's never went below 90 degrees.

[statesman]

How much did you lower the compression when you installed the supercharger?

[Jim_PA]

How much did you lower the compression when you installed the supercharger?

None. I figured the stock LS2 has more compression than the LQ4, so I actually went down a pulley size on the S.C.

[statesman]

How much boost are you seeing?

[Jim_PA]

About 7psi if I remember correctly.

[statesman]

Do you have a MAF sensor that you can temporarily enable?

[Jim_PA]

No, but I've thought about it. I'd have to re-do my PCV and air intake though.

[statesman]

My suggestion to you is to abandon SD... get a MAF sensor and run a MAF only tune. At 7psi you should just avoid pegging the MAF. Just be aware that GM utilized two different MAF sensors, one reads up to 512g/s (which is the one you want) while the other only reads up to about 465g/s.

The problems you are having with SD is firstly, that your IAT is getting badly heatsoaked and... secondly, that SD in general has another problem which not many people know about, but it's basically a compromise which GM had to make... and it means that you'll never get SD perfect even if you never suffered any heatsoak at all. Combining those two issues means your tune will always suck. Your only other real option is to create three tunes, summer/winter/fall... and keep swapping tunes as the seasons change.

[Jim_PA]

Thank you. Will take it into consideration. Is there a commonly used acronym for that config? OLMAF???

[statesman]

Why are you so obsessed with running open loop?

[Jim_PA]

Why are you so obsessed with running open loop?

I don't have an obsession with it. At the time I started, less things interacting seemed to be better.

[Jim_PA]

I believe I still have the MAF that came with the Eforce, but it's a Gen4 based maf. Probably not compatible with the Gen3 PCM. Will have to look for it.

[statesman]

If you want a really good open loop tune, then you need really good injector data... and very few people have that (just because injectors come with data doesn't mean that the data will be good). Closed loop will clean up any fueling errors and, provided your tune is in good shape to start off with, it has benefits over running open loop.

[statesman]

I believe I still have the MAF that came with the Eforce, but it's a Gen4 based maf. Probably not compatible with the Gen3 PCM. Will have to look for it.

It's preferable to have a MAF with an integrated IAT.... the IAT controls the conversion of desired airflow from mass to volume (complicated, but that's how it is) and proper IATs will give the PCM better idle airflow targeting. Using the heatsoaked IAT sensor in the supercharger means your PCM will have to do a lot of airflow trimming at idle.

[Jim_PA]

It's preferable to have a MAF with an integrated IAT.... the IAT controls the conversion of desired airflow from mass to volume (complicated, but that's how it is) and proper IATs will give the PCM better idle airflow targeting. Using the heatsoaked IAT sensor in the supercharger means your PCM will have to do a lot of airflow trimming at idle.

I could move from the IAT MAP to the IAT MAF, no problem. The IAT portion of the TMAP in the e-force is already calibrated in my tune for the LS3/7 IAT signal. Just not sure about the LS3 MAF sensor being compatible with the Gen3 PCM.

[statesman]

It'll work... you just need an adapter.

[Jim_PA]

It'll work... you just need an adapter.

Assuming you mean a physical adapter... -->? https://www.eficonnection.com/home/product/maf-sensor-connector-pigtail-4

[statesman]

Yeah, a physical adapter to connect to your LS1 harness. The product you linked to doesn't make it clear if that adapter services both MAF and IAT... just check to make sure the one you get does actually service both.

[Jim_PA]

Thank you, will give it a try. --

[joecar]

sounds like a plan :cheers:

[Jim_PA]

Is it safe to assume that the IAT/VE scaler needs to be just as perfect as the VE table before adding in any MAF or O2's?

2 classic blunders with my tune from last year... Baro update was set to 4,000 RPM (I could easily be in boost at that point) and I failed to realize my IAT scaler was in degrees Celsius, while I was entering values assuming it was degrees Farenheit. Easy to do, seeing as that when you flip to deg. F, the table goes all the way up to 284 deg. :throw:

VE is looking really good. Trying to get the IAT scaler reeled in and only making small ve changes at my 1.0 IAT scaler values at this point.

[statesman]

I'm a bit lost on what you're doing now. Do you have the MAF sensor fitted and working?

[Jim_PA]

I'm a bit lost on what you're doing now. Do you have the MAF sensor fitted and working?

No, I got a new wideband 02 sensor. I've been working on VE only for the last week. Wondering if I have to have the IAT/VE scaler perfect before adding something else in. And what is the logical next step? MAF? O2's? both at same time?

[statesman]

Oh man, that's funny. :laugh:

There is no logical next step when you're still wasting time on the VE table.

Try to understand this... the VE is NEVER going to tune up while you're using the IAT sensor on the manifold. You need an IAT sensor on the intake tubing. Fitting the MAF sensor and using the IAT on the MAF was the solution... but you're not implementing it. I told you to abandon the VE, but you persist with it. I really can't help you while you're maintaining your current trajectory.

[Jim_PA]

Oh man, that's funny. :laugh:

There is no logical next step when you're still wasting time on the VE table.

Try to understand this... the VE is NEVER going to tune up while you're using the IAT sensor on the manifold. You need an IAT sensor on the intake tubing. Fitting the MAF sensor and using the IAT on the MAF was the solution... but you're not implementing it. I told you to abandon the VE, but you persist with it. I really can't help you while you're maintaining your current trajectory.

Yeah, that's fing hillarious. So ve doesn't matter? Thanks for all your "help" good day sir.

[statesman]

Yeah, that's fing hillarious. So ve doesn't matter? Thanks for all your "help" good day sir.

Go back and read this whole thread. I told you to go MAF only... so yeah, the VE doesn't matter in that situation. With a MAF only tune, the VE only gets activated in the event of a MAF failure, so you still have to tune the VE but it's not critical and only gets tuned after you have the IAT in the intake working and after the MAF is tuned. In other words... it's the last thing to look at and it doesn't have to be perfect even when you do look at it.

If you don't like my "help", then that's okay... do things your own way.

[Jim_PA]

Go back and read this whole thread. I told you to go MAF only... so yeah, the VE doesn't matter in that situation. With a MAF only tune, the VE only gets activated in the event of a MAF failure, so you still have to tune the VE but it's not critical and only gets tuned after you have the IAT in the intake working and after the MAF is tuned. In other words... it's the last thing to look at and it doesn't have to be perfect even when you do look at it.

If you don't like my "help", then that's okay... do things your own way.

Maybe you should re-read the thread. If your help is at the cost of your condescending answers, please go away.