Problem with my Head/Cam 98 LS1 camaro - files attached

[ScarabEpic22]

Also, if you had a 99-02 PCM you could run COS5 and use the built-in N2O retard tables. Get the tune sorted first, then think about that.

[blackflag]

Added 23% to B5001 (MAF Sensor Calibration).

Also modified B3618 (PE Modifier based on RPM). It was really rich so I faded it into 12.61 to see how it does.

I'm going to go log some more data before getting into the VE table

[joecar]

...

I had the CC set under Edit > Log File Information > Vehicle Information. I closed EFILive Scan and opened it back up to make sure it would load the new calc_pids.txt. I guess it didn't save it when I re-opened the scan tool.

...

Yes, you have to Save the log file before closing it.

[joecar]

B5001(MAF) and B0101(VE): PCM calculates cylinder airmasss from these.

B3605(OLFA) and B3618(PE): PCM looks up these to know what EQR to command;

B3601(STOICH): PCM uses this to know what is stoichiometric AFR;

PCM uses those 3 pieces of information (cylinder airmass, commanded EQR, stoichiometric AFR) to calculate fuelmass required to meet the commanded AFR...


STOICH converts airmass to fuelmass, and commanded EQR multiplies this to obtain commanded fuelmass
( or another way of looking at it:
commanded EQR multiplies airmass, and STOICH converts this to obtain commanded fuelmass
can you see how this is equivalent...?)


e.g.
- if you increase the cylinder airmass, you cause an increase in fuelmass (can you see why...?)
- if you increase the commanded EQR, you cause an increase in fuelmass.
- if you increase the stoichiometric AFR, you cause a decrease in fuelmass.


So, the idea is to get MAF and VE correct, and set STOICH to the fuel being used... now what ever you set OLFA and PE to is the EQR that the PCM will deliver (as confirmed by wideband).

Edit: you have to start with injector tables that correctly model your injectors.


Some points:
- view all the fuel tables in EQR units; this makes you independent of the stoich AFR for different fuels (E00, E10, E85, and all in between).
- view the VE table in g*K/kPa, because this is what it is; this makes you independent of cylinder volume.
- log GM.EQIVRATIO instead of GM.AFR; this gives you 2 things: independence from fuel stoich, and the correct commanded fueling (see below).
- use the wideband lambda to calculate the BEN correction: e.g. for V2, BEN = GM.EQIVRATIO * EXT.WO2LAM1.

Some of us have observed GM.AFR and GM.EQIVRATIO being slightly different... we're not sure why/how, but GM.AFR seems to be smoothed over.

[rpmauto]

don't forget that on the 98's you will need to do your back up VE table as you get the main ve. (copy)

Forgot about the cos for n2o. I will have to look into that now that I have done the pcm swap.

[DrkPhx]

don't forget that on the 98's you will need to do your back up VE table as you get the main ve. (copy)

Forgot about the cos for n2o. I will have to look into that now that I have done the pcm swap.

Len - The backup VE table in the 98 PCM is worthless for a highly modified car because it's so "coarse" compared to the Main VE. Last year the MAF on my TA failed completely while driving which sent the car to the backup VE. Even though the values in the backup matched the main VE, the car would barely start let alone idle.

[rpmauto]

Gino,
interesting, I know the values were rough on the backup ve, I never even gave that a thought. Would work good enough on a stock engine to limp home, but not on a modified engine.

[WeathermanShawn]

Len & DrkPhx..

Are you guys saying that even if you fail the MAF on the 98 PCM, it is not using the VE Table we are calculating?

Us 1221256 OS's users need a little educating on this..

[blackflag]

Hey Guys,

Just got back from making a decent log run using the same CALC.VET PIDs used in the first log file. Only changes made were made in post #46. Added %23 to the MAF table and leaned out the PE table.

Before I started logging I went into DVT > Fuel Trim Reset > Fuel Reset.

How to the logs look? Car seemed to run strong and more responsive but roads were still a little wet. But I did get some good WOT pulls in.

I think max fuel trims were still %25 but I havent looked at them close yet.

[DrkPhx]

Len & DrkPhx..

Are you guys saying that even if you fail the MAF on the 98 PCM, it is not using the VE Table we are calculating?

Us 1221256 OS's users need a little educating on this..

The 98 PCM has a secondary backup VE table that is used when the MAF fails. The MAP columns are in increments of 10, not 5 like the main VE. Hence the coarseness.