Fueling adjustment ??

[2QUIK6]

I'm using TunerCat for an editor and I don't see anywhere to adjust fueling vs load or rpm or anything like that in a table??
The only table for fuel trim is the "PE Fuel Trim vs RPM" but what about non-PE? Am I missing something here as this was very straight forward on the TPI?
Thanks

 

[ijames]

There's basically two cases: in PE mode and not in PE mode. Not in PE mode the fueling is controlled by the MAF, the table of learned BLM's, and the O2 sensor, and there isn't any thing for you to change. In PE mode the pe-rpm and pe-tps tables get multiplied in on top of the fuel it would use in the same circumstances if it wasn't in pe mode. Yeah, there's also ae which gets done in pe or not but that's transient
PE is power enrichment and AE is acceleration enrichment

 

[2QUIK6]

Originally posted by ijames
Not in PE mode the fueling is controlled by the MAF, the table of learned BLM's, and the O2 sensor, and there isn't any thing for you to change.

hmm, maybe I don't understand my GN's ECM quit the same as my SD TPI since its not MAF controlled, but I would think that somewhere there has to be a table of fuel efficieny values, otherwise everyone chips would run the same when not in PE mode. For example, we all know that KB chips idle pig rich, somewhere there has to be a factor that is used to determine the pulse width at idle speed and all other non-PE rpm and MAF reading ranges. The BLM/INT values are used as a factor multiplied to the efficiency value, along with the PE values added on and temp adj values. The O2 sensor come into play determining if that value is "perfect", otherwise if it not the BLM/INT are adjusted to make that "perfect" AF ratio.
On Speed Density(non-MAF) cars its the Volumeteric efficiency tables are the main fuel curve settings.
Ok, so what do I have wrong here cause I'm confused as to how this ECM works if this isn't right??

 

[ijames]

That's the whole point of a maf system - you don't need that table of ve's. About all you can do is tweak the injector constant and the blm limits - maybe those kb chips (which I've never heard of as idling rich) have the inj const and blm limits such that the chip is sitting with the blm on the minimum at idle so it can't lean it out any more?

On speed-density you have a table of ve's indexed by rpm and map to calculate the maf. On a maf system you just read the maf. The basic fueling equation is:

inj pw = maf * desired far * blm * int * inj const * (corrections like battery voltage and coolant) * (pe-tps * pe-rpm if in pe) / rpm

If the engine isn't warmed up yet it stays open loop and adds in the coolant enrichment. Once it get warm enough to enable closed loop (and it's okay to go closed loop based on not-in-pe or other such) then it starts twiddling the int based on the O2 sensor. Once it finishes warming up and it's not-in-pe or other such, it enables learn control and starts twiddling the stored blms based on the int.

 

[2QUIK6]

Ok, I think I'm starting to see the picture. So if I needed to lean it out a tad in the lower rpm ranges like for better spool up as its pretty fat now off the line, I would first determine if I'm in PE mode, if so I could tweak the PE Fuel trim vs RPM table, and if lean on the higher rpms, I again could tweak it in the same table.
If not in PE< then really the only place to go is the inj. constant which will effect all rpm ranges and loads, but really only want to tweak the inj constant if the BLMs are bottomed out one way or the other.
Is that pretty close to what I have to work with...
Inj Constant,
PE fueling vs RPM
PE fueling vs. TPS%
Fueling based on temp
*
What about the MAX Inj. PW based on Temp?? Could that be tweaked to help get the needed results?
THanks

 

[bruce]

Originally posted by 2QUIK6
I'm using TunerCat for an editor and I don't see anywhere to adjust fueling vs load or rpm or anything like that in a table??
The only table for fuel trim is the "PE Fuel Trim vs RPM" but what about non-PE? Am I missing something here as this was very straight forward on the TPI?
Thanks

You have PE, and in there you have.
PE AFR as a function of coolant temp.
PE AFR correction for RPM
PE AFR correction for TPS

No none PE you have.
Commanded AFRs, and the min/ max O2 voltages.
You have a coolant temp enable for Closed Loop or Open loop.

Then you have the MAF tables and scalers.
The table entry times the scaler, divided by 255 gives you an interpretation of what the ecm thinks the gm/sec is.

It takes a ton of time to go thru the MAF scalers and tables to get things really correct. Then once you get the gm/sec and corresonding Gm/sec stuff right you have to go thru allllll the LV8 to get things into shape again.

Save dinking with the MAF scalers and tables until you're really clear on all the code, and have a WB. It takes alot of effort to get it all correct.