1988 iroc z28 355 heavily modded
auto tranny
165 ecm, 32b, maf tpi

I am trying to learn some tunning but i am missing the background. I have read a lot of articles including Tim's infamous one so now i would like to take a real life example.

Frame number 4135 (ease s/w converted to excel) shows
blm cell 3
blm # 126
integrator at 128
long term fuel trim at -1.6

a few frames later i have
blm cell 7
blm # 126
integrator at 129
long term fuel trim at -1.6

the next frame i have
blm cell 11
blm # 114
integrator at 129
long term fuel trim at -10.9

in the frames that follow the only value that changes is the integrator which tracks as follows:

127,126,126,127,129,131,132,134,134,134,134,134,134.....

Can you tell me what table i should be adjusting and why?

Is it desireable to try to attain 128/128 or do i really want to run rich here or have i not given enough info - e.g. o2 sensor readings (not from the stock one).

What can you tell me? Anyone?

Dave

 

Individual frames of data don't tell you much. You should look at the graphs of your scans, looking at several variables at the same time. I use Ease also, and I can look at 6 graphs at the same time. Try to look for trends, IE BLMs or INTs real low or real high. Then look at the airflow numbers. Then you can make changes to the MAF tables to get the BLMs and INTs closer to 128.

I would start with making changes to fuel curves first, then work on the spark tables. That is what I am doing now. I have left my spark table alone, trying to get my BLMs close to 128.

PS. You would have more adjustability switching to the '89 ARAP bin, which uses TC's $6E tdf calibration. It comes highly reccomended!

------------------
Best ET 14.413 @95.57 without
pulling valve covers or manifolds.
Also with stock 2.77 rear end!!!

 

When you say the MAF tables - are you talking about raising or lowering the gm/sec. In the 32b logic I think the ecm measures the air and then adds or subtracts fuel based on the counts it is fed. Is this correct. I have graphed this table in excel. Initially the counts go up in jumps of 32 then later 16. But my gm/sec increases don't match the ramp in the counts. They look more like the curve in a clothesline or a wire strung between two poles - they swoop!


I just wanted to know when it was appropriate to +/- fuel vs +/- spark.

Also I have both 32b and 6e. What tables would i mod in 6e for fuel. I have barely looked at that one yet.

I am quite willing to switch to 6e when i learn a little a little more {:~)

Thanks for the comeback!

David

 

You are right about the MAF tables. You would adjust the gm/sec up or down at a specific count number. The ECM takes the number of counts the MAF sensor is reporting, and uses the tables to convert that number to an airflow reading. It then uses that number to calculate load, or the LV8 number that you see. It uses this number, and several others, to output a pulse width to the fuel injectors. At least that is how I understand it!!!

The graphs of the MAF tables probably won't be linear, I don't think the sensor is. The MAF tables are the same in the $6E tdf vs the 32B, just that there are many other tables and constants to play with. Also, TC seems to be making more updates to that TDF, than the earlier MAF tdfs. Another neat feature of TC, is that you can graph a table and look at the numbers at the same time, then use your mouse and move a point in the graph, to make it more linear. (OR NOT!!)

My MAF tables start out changing by 64 counts, then by 32, and by 16 in table6. I think that is how they all are.

 

I have been looking for the BPW formula for a while. I know i saw one but i have been unsuccesful in finding it again.

My idea was to use the bpw formula and work backwards with the data dump from the ease s/w to figure out or get more insight as to what was going on.

Do you or anywone else have the BPW formula?

David