Fuel multipliers and tuning VE

[CDeeZ]

I've read around and I don't know if there is consensus on this issue but I know that some people prefer to totally disable fuel multipliers when tuning VE so that the process goes easier....

When I drive around datalogging it seems almost too easy to get into PE in the lower RPM.. ( 0 and 400 RPM cells both use a value of 25, 800-2400 RPM cells use 60 and so on...

I'm not as sure about how to go about dealing with AE for tuning the VE, but why couldn't I temporarily set the PE enable TPS table to say, all 60 while tuning my VE, and perhaps also turn off DFCO and/or DE?

I would think that disabling or limiting the fuel multipliers while tuning your VE would make it easier, and as long as you're not hammering on it with these multipliers modified I would also think that the engine would be fine.

Thoughts?

[EagleMark]

I don't know why anyone would do that? I would never mess with multipliers. Disableing PE is a must to get correct BLM numbers for VE tables.

I have a new $42 but not thouroghly tested, use the catagory instead of Paremeter Type and there is a folder for things to turn off for data logging. It all works, just haven't used it enough to know if it is complete. There are also hacks to bin file built in to data log other items, use the Read Me Paremeter comment option for details of each.

[CDeeZ]

THanks for sharing that new mask. You wouldn't also happen to point me in the direction of the datastream def to match, the v4.xdf.....

So the only things I need to deal with when getting ready to record BLM for tuning VE are the things under the "Turn off for data logging" Does that list cover everything that should be dealt with before datalogging??? Air diverter? That's some emissions stuff right? If so I don't think I ever had that so I should be able to turn that off and leave it off right?

[EagleMark]

Here's my newest ADX file, they are upgrades to old ones and will work together, when I have time to proof them they will replace the ones in the $42 info thread. Since I have a factory $42 rig and do lots of off road conversions with this ECM I am constantly working on these, but I don't think there's much more to be found other then hacks.

Some $42 vehicles don't have air diverter, when you look at it, it will be Max temp already.

Yes things in the Turn off for BLM are what is needed to get good BLM data to adjust VE tables, then when you turn them back on your PE etc... will work properly. Everything is an adjustment to perfect VE tables.

I'll throw you a few more bones, look at the spark table in the bin attatched with graph view and learn to use the compare function and see which spark table you would want to start with? Remember spark or fuel is a calculation of the cell your in and four surrounding cells, smoother is easier. This table puts out almost exact spark advance as stock spark table at all times except where GM needed to pull or push and area to meet emmissions. You can add 2 to 4 degrees to this table outside idle spark on stock motor safely for all weather year round.

Also attatched is spreadsheet for doing VE tables built by Dave W. Once you learn to use it you can take your BLM history CTRL C for copy, use the spreadsheet and have entire VE table adjusted in one minute.

Datalogging should always be done totally warmed up and driven or at least a WOT blast, then start data. When your close and totally warmed up pull batterey power to clear learn, start vehicle and watch for closed loop, then do one more data log and adjustment.

[CDeeZ]

Thanks for that Mark. What exactly IS the air diverter?

I compared the spark table in that bin you posted to that of the one I'm using and the difference is minimal, just looks like mainly a little more spark in the 30 and 40 KPA columns

Yeah I've been using Dave W's VE spreadsheet for a bit. One thing I notice though is when I copy my BLM values from TPRT and paste them into the spreadsheet, there are values showing up that were NOT recorded BLMS... Did Dave make that spreadsheet so it extrapolates certain cells or what is going on here?

I've been logging by getting up to operating temp, then clearing all tables and starting a recording of the log... Would it be better to fully remove power from the ECM as you're suggesting??

[EagleMark]

Air diverter is a valve that lets air from pump into exhaust system for emmissions. Most $42 vehicles don't have it.

When using the spreadsheet highlight your BLM history table completly, hold down Shift and click on bottom right cell then top left cell then copy ctrl C. Then highlight the entire table in spreadsheet, same way, bottm right and top left and hit backspace to delete everything, then ctrl V to paste and when box opens check tab. Should fill in the blanks just right.

There's very little change in the spark other then it being smoothed, compare both with graph view and you will see it.

The batterey disconnect is a faster approach, it clears BLM learn so you get starting BLM, not learned BLM.

[CDeeZ]

Is and air diverter the same thing as a smog pump?? If so I don't have that.

How many runs with Dave W's spreadsheet should it take to get the BLM dialed in???

I'm still at a loss as to how the 3200 RPM range of cells in VE1 can cover EVERYTHING BEYONDthat RPM range and still be accurate for the 3200 RPM range...

[EagleMark]

Yes Smog Pump.

I don't know how many times through the spreadsheet? I do mine live and rough them in, then maybe 3 times and can't get any better.

It uses the last cell after 3200 RPM, same as it would without VE2, but now no adder, or in most cases limiter as usual VE2 table gets lower as RPM increase.

What bin did you have that was the same VE2 throughout? I've never seen that?

[CDeeZ]

OK good to know.


I was just thinking that the VE would be different at 3200 RPM than it would be at say 4000 RPM, I'd assume it would be less at the higher RPM, so I was thinking that if you tune for one then the other will be off? If the ECM uses the last cell in VE1 that it was in, whenever the RPMs exceed 3200, and if VEs typically decrease with RPM, how do you tune for less VE at the higher RPM, W/O screwing up the VE values for running along AT 3200 RPM?


ASDW9544 is the bin I started with. And it has the value 39.06 from 400-3200 RPM in VE2

[EagleMark]

VE does not decrease with RPM. Look at any VE table and it always goes up with RPM and load, never down. Except in a case where it is a limiter like VE2.

I see what you mean about the same till 3200 RPM, but after that they all drop as a limiter, not because of need. Before I did mine this way it would fall flat on it's face and shift because of the limiter, now I have to lift the pedal to let Auto trans shift or it would keep reving. I changed PE to 11.5 to 1 AFR to get it to read 12.8 to 1 on Wide Band.

[CDeeZ]

I stand corrected.

So any time you're dealing with a 7747 you just zero out the entire VE2 and only worry about VE1 that only goes up to 3200 RPM??

[EagleMark]

You can ask several differant ways several more times and the answer will always be the same.

It's worked for Tuners better then I and has worked well for me, from stock to slightly modified to a 440 Mopar Six Pack Engine converted to TBI that revved to 5200 RPM...

It's such an easy, popular and available ECM that I think I'll give a shot a reworking the fuel table to 6400 or? as Robert suggested, but ain't happening till winter. It's been so long since I have seen sunshine and it's almost here!

[CDeeZ]

Sorry for beating this question to death, just trying to wrap my head around it.


That would be awesome if you whipped up a full size fuel table for the 747, I'd offer my help but not sure I have the expertise to tackle such a task, but nevertheless.

[EagleMark]

I had a hard time with it myself the first time. All is well.

Wish we could get Robert to buy an old 7747 truck so he had something OLD to play with, he'd have this whipped in no time...

[CDeeZ]

You can add 2 to 4 degrees to this table outside idle spark on stock motor safely for all weather year round.

What do you mean by 'outside idle spark'? I'm going to try adding a few degrees to the whole table as you mentioned and see what kind of effect that gives me.... Is there a range of cells I should stay away from when adding these few degrees of spark or can I hit the whole SA table with 2-4 additional degrees???