What is the different between Short Term and Long Term BLM?
I have run my 87 TPI 305 with a APYS (89) EPROM and do some data logging (17 minutes) with DataMaster and when I read the BLM in L Term and see that it is rich above 3000 rpm and lean above 1600 rpm till 3000. This doesn’t show at the S Term.
So what is the different, where should I look to got to the next step (Lean out by height revs)
See the pictures to understand what I mean.
Please let me know what you think!
Regards,
Cobra289

 

Her is the screen shot

 

THe Long Term (BLM) will adjust when the Short Term (INT) can't adjust enough to get the desired mixture. In normal operation, the short term will cycle across 128, above and below, which in theory, that should get your O2 going above and below 450 mV. When the INT stays below 128, the BLM will adjust to below 128 to keep the INT cycling across 128.

The reason GM did this is for a catalytic convertor to work properly. The run it a tad lean for a few ms to get some extra 02 into the converter, then a tad rich to keep the car running right, and the cat use the extra O2 to burn the extra fuel.

Sounds strange, but that's how I've had it explained to me!

Now, in burning your own chip for power, all that goes out the window, excepr for how the BLM and INT work together.

HTH....

 

Cobra289,

It appears your Long Term corrections are maxed out at some of these points. I think you should use your long term graph to guide you to the changes you need to make and ignore the short term graph (for now). From what you've posted, you're swinging from lean to rich throughout the operating range rather severely. Once you can run the same test that generated these graphs and have the long term graph indicate neutral, start looking at the short term graph to finalize the tune.

Good luck!

 

OK thanks for your explanations guy’s I learn two things today, but what next?
Sorry I am a newbie, I have only play with the “Flags” and “Constants” but now I need to go in the “Tables”

I use the TunerPro to edit the EPROM (PROMinator) ($6E mask in a 165 ECM)

I have selected the Table “Maximum Air Flow vs. RPM” is that the correct way?
See the picture with the changes that I made.

If you are so kind to see my DataMaster UNI file you can find at:
http://www.donostia.demon.nl/20-05-2004.zip

Regards,
Cobra289

 

If you save your data logs as CSV files anyone can look at them.

The “Maximum Air Flow vs. RPM” table is a limiter table. I would add 60 gms/sec to every point of that table (the one you already changed to) and be done with it (to a max of 255 gms/sec).

To get the closed loop (non-PE) fueling correct you need to change the MAF scalar tables. There are six of them that cover the 0 - 255 gms/sec range. Lots of info on how to do this in the sticky's up top.

RBob.

 

Thanks RBob,
I will change this table and MAF Tables.
I have read every thing on the sticky's and I think that I have a brain cooking disaster.
The more I read the more I loose my confident. I thought that I know something about cars.

I put a CSV file of the same data logging I hope that you are willing to check and give me a hint about what next.
http://www.donostia.demon.nl/CSV.zip

Regards,
Cobra289

 

Have you zero'd out the SA term at $23? This is important as it is an ALDL SA adder value. Whenever you data log this SA value will be added to your current SA.

Another reason I bring that up is because of the knock retard that is happening. Look at the run starting at record # 6061.

Another problem is the BLM cell 15 value of 117. Someplace in the MAF tables BLM cell 15 is being learned in to remove a lot of fuel. This becomes a problem in this run. See #6072 through 6082 and how lean the O2 is reporting, then the knock starts.

There is also knock at every shift. Change the SA term at $23 to 0, find the rich area that is dropping BLM cell 15 and lean it a little. Then data log some more.

RBob.

 

Looks like the MAF scalar term for 50 gms/sec is rich. See the area between record #4320 and #4327. The INT is dropping like a rock dragging the BLM cell 15 with it.

What I did to find this was to start at the end of the log file and go back in time toward the beginning of the log. I looked where cell 15 was in use and where the BLM was dropping. This showed where it was being learned in.

RBob.

 

Hi RBob,
Thanks that you have look to my data log.
When you talk about SA term at $23 what do you mean? Is that and “Spark Advance” the $23 is the hex location?
I use Mark’s TunerPro where can I find this to bring it to zero?
Is that the “Spark Reference Angle – Base Timing”?
So this value should be zero during the data log and then after that should be changed to the original 5.98? is that what you mean?

I see that at the #6072 the BPW is dropped to 0.27 that is Cell 15 and the spark advance is 42.2 degrees that is beyond the max. at the “Spark Advance Table” (40.08)

Thanks for give me a change to learn.
Regards
Cobra289

 

The $23 is the address of the SA term to set to zero. It is not the “Spark Reference Angle – Base Timing”. If it isn't in the ECU then use a hex utility tool, go to address $23 (hex address 23) and enter a zero.

Re-calc checksum and burn.

RBob.

 

Thanks again.
That’s make more sense.
I am not used with hex, but I will find the way.
Regards,
Cobra289

 

RBob -

What was GMs reason for adding the (standard in $6E) 8.09 degrees of advance when ALDL is present? It doesn't make much sense to me.

Mark

PS - Cobra - thanks for the email. I'm happy you were able to add the ALDL S.A. item to the 6Ev011.ecu using TunerPro.

 

That explains why vehicles run different when in ALDL mode! I noticed it the other day when working on a car that was running a newer flash ECM,and I'm sure it has this same term in it's code.