Has anyone ever figured out how to add lean cruise tables to a 2000 LS1 PCM? I know it's "there" and "disabled" in the 01/02 OS...just curious if anyones ever been able to add it to the 2000 OS.

 

If you have EFILive, PM me, I can fix it

 

Opp, didn't realize you where looking at a 2000. This only works on the 01+ tunes

 

I think your only option is to either 1) use open loop, tune your VE, and log your cruise conditions and then lean out the OLFA under those conditions or 2) get a raw bin of your calibration and alter it in the raw code. I have nop idea how to do that, though.

 

Yeah, I don't want to run open loop, my VE is tuned right now running speed density, my fuel trims are great...but I prefer to keep closed loop control on the car. I can flash a 2002 OS into the current PCM and do some hex editing...but I think I might be better off putting a newer PCM into the car and running a 2004 GTO operating system...the hardware to run that operating system is in practically everything GM built in 2004...very easy to find it in the junkyard.

 

aren't some/most 2004 pcm's non IAC, so you will need a gto service number pcm?

Ryan

 

The GTO PCM is the same as most of the trucks and whatnot...just need to run GTO code in them. Far as I know the hardware is the same.

In fact, I believe that code would work in any of the following hardware part numbers (from 2003 through 2007) 12576106, 12586243, 12586242, 12583560, 12583561, and 12589463. The 2004 GTO is the only one of them (that I know of) thats drive by cable (normal IAC) AND has lean cruise enabled without a patch.

 

So something else I just thought of...why can't I just run 2001 Holden Commodore code in my PCM? Those care ran lean cruise, didn't they? Looking through a stock 2001 Commodore program from the HPTuners repository shows data in those tables.

I'll have the car back this week I hope...and I'm going to try it (it'll cost me a couple credits to license the file to my software...but I think it's worth it).

 

If you have EFILive you can upgrade to a 01 OS and do the cax file modification to enable it.

 

I don't have EFI Live...I have HPTuners...but I don't think the Holden code will need the patch at all anyways.

 

10-4. I don't know what to tell you about the running the holden code!!

 

After looking at the Holden program more...I don't think there's a fuel gauge segment in the code...or at least not one like the F-Bodies segment...so I guess if I were to flash it in, I'd have no gas gauge.

I'll look into patching a 2001/2002 Camaro program instead.

 

Your other option is to push the O2 sensor switchpoint
values, in the Airflow Mode cells that pertain to highway
cruising, to lower voltage levels. This can get you into
the 15:1 - 15.5:1 range but closed loop. You can be
very specific about the airflow "binning" into mode cells
(airflow mode vs airflow) if you want. Use the wideband
to see where you're really at, and tamp down the levels
incrementally until you get the leanness you want, or
run into KR or something.

I wouldn't go below maybe 150mV, but look at your NBO2
bottoming voltage to see what's normal for your car and
give it maybe 50-100mV extra slack.

This is not lean cruise per se, but it has a similar effect
and is not open loop.

 

I don't want to do that though...because then I need to re-figure what all of my other actual calculations are in the PCM...the PCM has a constant that defines what Stoich is, and all of the equivalency ratio's work off of that. If I change that switch point, I am changing stoich, and then I need to measure what that is, and put it into that constant in order for my equivalency ratios (for open loop fueling, power enrichment fueling) to be "right"...I'd prefer not to do that as stoich with the fuel I'm able to run up here is something like 14.67:1...I am an engineer, so in my head numbers need to be right...by telling the PCM that stoich is a leaner value...thats not "right" in my opinion.

Basically it all comes down to...I want my VE tuned perfect, so when I am in open loop (when it's cold), it's actually achieving the commanded AFR...and so that when it's in power enrichment, the commanded AFR and the AFR on the wideband are actually the same number...and I want my stoich value that all of those numbers are based on, to be the actual stoich value for the fuel I can buy at the station down the street from my house.

I know that may be a bit ****...and I'm not trying to call the other way of doing it a hack...I'm just an OCD engineer and I get upset thinking numbers like that aren't actually right (although I don't care if the car thinks it's a holden, or a pontiac, or a chevrolet, or anything else lol).

 

PCM has a stoich value, but the actual O2 voltage that
corresponds to it is variable. I've seen 450mV turn into
a 13.5:1 idle AFR out the back, and pulled it back to
14.7 (ish) by pushing down the voltage threshold to
300mV or so. F-bodies use 350mV range, stock.

The whole reason for the table is to "fix" the variability
of the sensor. It only alters closed loop, not your VE
accuracy (unless you were using the LTFT+STFT as
your guide, in which case you'd have been embedding
any of the O2 sensor : AFR=stoich error all along).

 

I agree...but my point is, in my car, it's already at ~14.6-14.7:1 with the switching values I am using, first it was not at that AFR, and the VE was a little off...I corrected the switching values to correct the stoich AFR at idle and outside of PE mode (different airflow modes), so they're not stock values in those tables, I run NTK sensors and I've found they switch very fast and seem to work very nicely, they have good heaters in them...after I had that right, the LTFT and STFT were off, and correcting the VE tables cured this (the car is running speed density, not MAF), the VE tables don't affect your final AFR in closed loop as long as they don't push you beyond the limits of the fuel trims...they affect your AFR until the fuel trims have had time to learn.

By calibrating all of that the way I did, I know that my airmass calculations inside of my VE model are very accurate and my constant that my PCM knows to be stoich is what I believe the fuel I'm buying to be. I setup the numbers in my power enrichment tables based on that stoich value and math with the equivalency ratio, and measured it with a wideband (my own as well as the one the dyno owns...they both read the same numbers) and found that it was extremely close to what my PE tables were commanding. Again this tells me that the tables in the PCM for everything from my O2 switch points, my stoich constant, and my VE are calibrated properly allowing closed loop to function as it's intended to function. If I were to put the car into open loop today, and drive it 400 miles staring at the wideband, I would fully expect it to read the same values that I have commanded in the open loop fueling tables.

Spark advance is referenced to cylinder airmass, which is calculated (in my car without a MAF)...I wanted it calculated properly which is why I went through so much effort to get the O2's switching spot on, and then get the VE tables nailed down as accurately as I could to teach the PCM where stoich is without it relying on compensation from fuel trims. That compensation is still there if I get a tank of bad or different gas though because I'm allowing it to run closed loop and not lieing to it.

Now that I have that all calibrated properly (or what is my view of properly), I want to use actual lean cruise to kick the car out of closed loop when it's cruising, and lean it out according to the equivalency ratios. When the equivalency ratio commands 16.2:1, I want it to be actually achieving that...I can verify it with a wideband, but the PCM cannot verify it on it's own, and I don't want to drive the car staring at the wideband wondering if it's there or not, I want to drive the car paying attention to driving the car, as well as enjoying the car and it's stereo, knowing that it's commanding and achieving the correct air fuel ration despite being out of closed loop.

If you adjust the switch points and use them to lean the car out or richen the car up, and don't change that stoich constant in the PCM, then the equivalency ratio's in any open loop tables (cold start, lean cruise, power enrichment) are not accurate. I agree with you, as long as you change that constant...they're right again, even if it isn't actually stoich...but just what you want your cars PCM to think is stoich(hence why they're not air fuel ratios, but rather the multipliers used in the calculation to determine air fuel), but stoich, with regular pump gas around here is currently between 14.6 and 14.7:1...it might be changing depending on additives during the different seasons, so that is the value that should be in the stoich constant in the PCM, and that is the value that should be worked with...again...in my opinion.

 

I should also mention...the other reason I want lean cruise to work properly, is that it will allow me to put the AFR Spark Correction Table to use to add spark when leaning the car out at light load to actually bring up the efficiency.

 

i have a patched calibration (not a holden platform, genuine f-body os), although i haven't tested it in an actual vehicle. whoever is interested can send me an email directly to programming@pcmperformance.com. i don't like to discuss this particular subject in open forums.

-alex

 

If alex cant do it for you. I suppose i can modify the code for you.

 

after the lean cruise is enabled can it be then be tuned with hptuner's or will it need to be tuned with efi?