LT5 ECM Tuning thread

[tpepmeie]

Look who's come out of lurker mode. How the heck are you Tyler? Figured you would join this thread eventually.

Dominic, what I posted was for the BFXB calibration. Ron has a '93 (?), so obviously the tables are not at the same address. Not hard to find, though.

Let's get some talk going about how or why things work in the LT5 calibration, rather than just table addresses.

Todd

[Tyler Townsley]

Originally Posted by tpepmeie

Look who's come out of lurker mode. How the heck are you Tyler? Figured you would join this thread eventually.

Dominic, what I posted was for the BFXB calibration. Ron has a '93 (?), so obviously the tables are not at the same address. Not hard to find, though.

Let's get some talk going about how or why things work in the LT5 calibration, rather than just table addresses.

Todd

Been a little busy.

http://www.ncrsfl.org/Events/30thReg...thRegional.htm

OK. Something to think about. Just what do the spark tables do and how can manuliptating them solve Rons problem?

Off to the Lions Den for awhile.

Tyler

[XfireZ51]

Todd,

I thought the $D0A Mask was for the 92 which is what I was asking about. Are you saying that the code varies by broadcast code?
I was curious about the Prop Gains for Shawn's issue since he was complaining about a decl surge.
If Ron's problem isn't mechanical, I would look at lowering the O2 sensor R/L voltages. I'll be glad to discuss why I think this may help as an exercise for the members of this forum.
I would also suggest that if the members here are interested in reading material there are several good writeups available on 3rd Gen dealing with tuning in general, PID Controls, and the function of various IAC parameters.

Jeff,

I had previously asked Todd about inserting the WB data into the ALDL datastream. He brought up 2 very good points however for keeping it separate:

1. The ECM only sends data up to 6300rpm

2. My ZT-2 WB captures 35frames/sec, a data rate about 2x as much as the ECM. At WOT having that additional data makes tuning more accurate. The ECM data will "lose" significant portions of the scan even below 6300rpm.

So tapping into MAP and RPM outputs for the WB scantool would be the better way to go IMO.

[-=Jeff=-]

While I agree the ZT-2 datalogging would be better since thereis no RPM limit and the speed is faster, having it being able to connect to the ECm and show up in the ALDL datastream would be nice if you are using it to troubleshoot problems, it helps to keep the W data correlated witht he BLM / INT especially when doing part throttle tuning (where you typically are MOST of the time). Even though I have my Z now it does not mean I am going to do WOT blasts form everystop light.. just 1/2 of them

[tpepmeie]

Yes, table addresses can vary by broadcast code (but are generally the same for a given Mask ID.).

I wasn't sure which problem we were trying to solve: 1) surging on decel w/ stock and modified chip, 2) passing emissions with highly modified LT5 w/ big cams.

$D0 is different than $AF in some areas, though I don't recall if these tables are in same place. Will have to check.

Todd

[Pete]

Originally Posted by Tyler Townsley

OK. Something to think about. Just what do the spark tables do and how can manuliptating them solve Rons problem?

Off to the Lions Den for awhile.

Tyler

Freaking computer geeks but still haven't answered this question.

Pete

[-=Jeff=-]

Originally Posted by Pete

Freaking computer geeks but still haven't answered this question.

Pete

That is because we were waiting for you

[XfireZ51]

Originally Posted by Tyler Townsley

Been a little busy.

http://www.ncrsfl.org/Events/30thReg...thRegional.htm

OK. Something to think about. Just what do the spark tables do and how can manuliptating them solve Rons problem?

Off to the Lions Den for awhile.

Tyler

Tyler,

The spark or SA tables are just that. Its 3D tables of the commanded
spark advance (SA). Based on the rpm and kPa at any given time, the ECM will command the stated timing. That's the simple explanation. However, there are several ancillary tables that are also used to modify the final SA depending on the parameters that are met (i.e. Idle, warmup, Decel, TPS, CTS etc.)With just what Ron has described I'm not convinced that the SA tables are the solution for Ron. Not sure that there is a solution for Ron. Getting some scantool and WB data would help in trying to narrow it down. But with big cams and more overlap, there's a tendency to overscavenge the chamber exposing the NB O2 to more air.
That causes the ECM to think the motor is running lean which in turn causes the ECM to try to "richen" the mixture which then increases the unburned HC. Lowering the O2 voltage swing points at lower airflow tells the ECM that the motor is not running lean. That's why the WB could be reading stoich but the BLMs show lean.
That's why I'm interested in the R/L O2 voltage tables. They're in the calibration just haven't been created in the .xdf or .tdf.
Make sense?

[XfireZ51]

So have we discussed everything that needs to be discussed for tuning our ZR-1s?

[-=Jeff=-]

Originally Posted by XfireZ51

So have we discussed everything that needs to be discussed for tuning our ZR-1s?

Apparently, since nobody has a Decent definition file for them. I wish I knew how to decode them , if I had the know how and the means to do itmost any ZR-1 owner would be able to benefit fom them.

Unfortunately I don't know where to start on decoding a MEMCAL (Bin) file for our cars or any for that matter