What table to look at for base fuel map and how to see it

Discuss anything TunerPro related.

Moderators: Mangus, robertisaar, dex

Post Reply
bcollida
Posts: 12
Joined: Fri Feb 05, 2010 8:02 pm

What table to look at for base fuel map and how to see it

Post by bcollida »

Sorry, looked did some search but didn't see an answer to my basic question.

I am poking around on a downloaded bin file with tuner pro to feel my way around the file and Tuner Pro.

I was expect to see a table with rpm on one side and some type of load across the top that shows values in the table to control injector pulse.

Instead all I see are MAF table 1, MAF table 2, MAF table 3, MAF table 4 which are simple two column tables showing voltage and corresponding Grams per sec.

Or I was expecting to see a table in tuner pro that shows something that corresponds to cells 1 through 16 like I see in the hystogram presented to me when using DataMasters to log data.

Can someone point me in the right direction.
I can not find the table I was expecting to see
robertisaar
Author of Defs
Posts: 962
Joined: Sat Feb 21, 2009 3:18 pm
Location: Camden, MI

Post by robertisaar »

from the sounds of it, you're playing with a MAF based system, which won't have a table for load vs RPM for fueling. the MAF does that based on it's signal alone(well it does have slight correction due to air temp). spark on the other hand, does use a load vs RPM table to determine spark advance.

and the 16 cells from datamaster are your BLM cells. they are based on a 2D table that references RPM and airflow. they aren't terribly important, but do merit being looked at every once in a while.
bcollida
Posts: 12
Joined: Fri Feb 05, 2010 8:02 pm

Post by bcollida »

Yes. I have a 1989 Corvette MAF based system.

When I data log, the BLMs are mostly 15% lower that 128 meaning that the computer thinks the engine is running rich and it is pulling fuel out of the mix.

I have done a check of all things mechanical that I can think of so I thought I would experiement with the calibration. Kind of phase two of my self education process on tuning anyway.

The engine runs well. The spark plugs look good. the O2 sensor swings back and forth. Its just that the BLMs mostly show a rich running engine.

Except at low idle "fuel trim cell" 0 shows a lean condition and "Fuel Trim Cell" 6 shows a BLM of 128, right on the money.

One side of me say to just let it go and not worry about the BLM being off.
The other side says, something must be wrong either mechanicaly or with the tune and for the long term health of the engine I should figure it out.

The engine build and chip was purchased as a package so I have the option of calling for help. But being how I am, I wanted to have a pretty good idea of how all the moving parts work or don't work.

Also I suspect that the engine builder mostly tuned the engine to work at wide open throtle and probably didn't spent much time working on the part throtle parts of the tune. Again the engine seems to run fine.

The DataMaster "dyno" calculator pegs the motor at about 410 horse power which what the engine was suppose to make.

Given the above.

1) I'd like to see if I can improve the tune on this engine
2) Can you give me a clue on how to analyze the information I gained from the Data Master data log and apply it to these MAF tables?
3) I thought I would be adjusting injector pulse width timing instead, these MAF tables look like I am adjust Grams per sec of air. which makes no sense to me

I sound pretty lost.
robertisaar
Author of Defs
Posts: 962
Joined: Sat Feb 21, 2009 3:18 pm
Location: Camden, MI

Post by robertisaar »

MAF is still pretty foreign to me, and from what i understand, you have to change the injector constant to bring fueling in line. then if there are just spots left, you play with the MAF tables. or at least that's what i've read.
bcollida
Posts: 12
Joined: Fri Feb 05, 2010 8:02 pm

Post by bcollida »

OK, thanks that sort of jives with a brief conversation I had with the engine builder. the couple of efi tuning books I've read sort of gloss over this. they talk about MAF and Speed density and then continue the tuning example with a VE table.

Thanks for the direction I'll try to do more research taking the approach you suggested above.

I appreciate your thoughts.
robertisaar
Author of Defs
Posts: 962
Joined: Sat Feb 21, 2009 3:18 pm
Location: Camden, MI

Post by robertisaar »

either thirdgen.org or one of the turbo buick forums would be a good place to gather information.
Post Reply