How are the MAF counts calculated by the ECM, in regards to the Fq output in Hz?

 

Things are set up that way.
The table allows you to get a general idea of what entry is equal to what gm/sec.

It's Table Scaller x table entry divided by 255, equals Gm/sec..

So on table 1 with a scaler of 8, and a table entry of 128, that would be 4 gm/sec..

So in your data logging if you saw a lean spot at 4 gm/sec, you'd want to increase the 128 to like ~135.

Yes, it takes a little getting used to..........

 

In the LV8 vs Injector Pulsewidth table, I'm trying to figure out how the ECU comes up with Counts, specifically.

The MAF puts out a varying frequency, somewhere between 32Hz and 150hz, and the ECU converts that into 'counts'.

How?

 

Maf Fq = ?? counts *bump*

 

frequency = 1/(counts * 15.26 * 10^-6). Basically, the computer counts at 65 KHz and how far it counts between each pulse from the MAF are what you see.

 

How can that be? From what you are saying, a higher frequency should have less counts - @ 150Hz, the pulses are MUCH closer than @ 32Hz.

Yet the MAF tables show an increasing 'Counts' value. It would seem the higher the frequency, the more counts.

Plugging in 1600 Counts into that formula, yields a value of 40.96. Now, whether or not that's actual MAF Fq in Hz, I can't say.

Plugging in 1500 Counts yields 43.68. Again, not sure if this is actual Fq, but I doubt it. - The point is, that for more counts, you should have a higher Fq value. Or is there more going on?

 

I guess I should add in that there are two ways the pulse accumulator may work. It can either return the # of counts between each pulse which will be a period, or it can jsut count each time it recieves a pulse and return that. If thats the way it works then that number would be proportional to frequency input. Im not real familar with what hardware is in use so maybe someone can elaborate on exactly how it works.

 

Anyone familiar with the hardware?