A friend has an 89 Formula with a 383 he just got running. We need help with the programming aspect. The car is a MAF, and we've sucessfully burned several chips for the car getting the idle and such corrected.

The question is at idle the BLMs are around 120, the Intergrator is showing about 108, and the Cell is showing 4-6. I understand the car is idling rich, but what does the Cell number represent? I cannot find anything to reference the Cell number with a MAF car as you can with the SD cars.

From what I can understand so far, the MAF tables need to be modified to adjust the BLMs to the 126-128 range with the Integrator maintaining 128, or as close as possible.

Going on that basis, the car is pulling about 14g/s at 1000 rpm. We've got it idling at 850-900 right now. Do we use the MAF calculation (15/24*256) to get the value for the MAF table at idle and insert this value into the scaler table?

Also, would this value go into Table 1 at 0, 64, etc? How do you know which Table value you need to change, or do you find the one which comes closest to the gm/s you need and adjust that value? for example, the stock values for table 1 are:
0:64
64:36
128:50
192:68
256:93
320:212
384:153
448:193
512:246

Which would make the 384:153 the scaler it is using for our idle? since the 153 would give us the closest gm/s flow rate to what we are pulling (14.3 vs 15).

While we are on the subject of MAF tables, in theory, the higher the number in the MAF table, the more fuel will be used at that gm/s?

I'm just trying to make sense of the MAF programming and how to adjust everything.

Any input would be great.......

 

What does the Cell number represent?

Cell# is based on RPM and LV8.

The question is at idle the BLMs are around 120, the Intergrator is showing about 108?

Yes, you are runnign rich. Let the Integrator stabilize (keep at the same RPM until INT gets to 128) then adjust MAF#1 table accordingly. I use the % method to change MAF tables if needed.

Yes the higher the MAF gps the more fuel will be injected.

I am no expert but this is how I do my chips.

Good luck.

 

OK, so the idea is to let the car run at the RPM until the INT stabilizes at 128, then see what the BLM is at and adjust the MAF scaler table accordingly. so if the BLM was at 120 INT at 128, then you are ready to adjust the tables. In this case you are running rich and you would lower the value in the MAF scaler table which corresponds to the gm/s you are pulling at the RPM being tested. Does this make sense?

Thanks for the help....

 

Ronnie, if you look through the archives of the GMECM mailing list* you will find references to the BLM Cells of a MAF system. I found it very interesting.


DANIELEK, how do you choose which MAF table to be in at the certain gr/s if that value appears in more than one table? I'm a bit confused about that point.


*if you type site:www.diy-efi.org into the google search box it only looks at that site. add the additional terms you want to find.

 

Alex: it's ROTTIE, not Ronnie.

As for the MAF tables, there are six of them. The first table covers 0-22 gm/s, the next one covers the next range etc.

If you open the first table, it has 9 values you can change. To get the gm/s for the value use the following: value/256*Table Scale Factor = gm/s

If you calculate the first table out, you can see the gm/s ranges from like 4 to 22, pick the one which is closest to the gm/s@rpm you want to adjust, and then change that value accordingly (up for richer, down for leaner).

Does this make any sense to you?

I'm just starting to figure all this out......

 

I THINK YOU GUYS GOT IT RIGHT.

The values in MAF table should not be the same IMO, they could be close within eachother but not the same.

Are you using ARAP based MAF tables?

They are the best to start with. That is what everybody is saying.

 

LOL, sorry Rottie!

DANIELEK, I guess I didn't explain it very well. What I mean is BLM cells 0 - 3 (not maf table)... these are the similar gr/s airflow, but different RPM. I get different BLM values depending on what cell I'm in. I was wondering if you knew how to deal with this.

 

Ok, i see what you mean my .

Actually i am going through the same problem as you.

This is what i can suggest:

- example: if my car spends most of the time in cell#6 at 23 gps and it has the BLM of 128 and if cell# 7 kicks in at the same gps (but does not stay on for a long time) and it has the BLM of 119
I leave it alone. Unless I am a way off.

In the above example I would lower the spark table a little bit at that particular RPM/LV8 to compansate for that.

Lowering it gives less fuel and increasing it give more fuel.(i think i got it right)

Try it and see what happens.

Let us know what happens

 

Good idea!

I'm actually playing with the cell boundaries right now. My car is almost dead on in cells 4, 5, 6, so I lowered airflow boundary 1 and raised #2, so I run in these cells more often (instead of 10, where I am rich). I'm not sure if it's the right way to do it, but I'll do some more serious testing next week to see if it helps.