RevGTO

iTrader: (12)

How important is linearity in the progression of the MAF Hz scale? I'm tuning my MAF for full-time open loop. Comparing commanded AFR to WB AFR, around idle I'm fine. Cruising and light throttle I'm a little rich. WOT I'm a little lean.

I have to increase some sections of the MAF table and decrease others. Is it important to keep the transition between cells very gradual as they are stock, or can the transition be more abrupt in certain areas without causing trouble.

I hope I'm making myself clear ....

YellowToy/A

iTrader: (1)

They should start from small and get bigger. I have seen some with a pretty good jump. I have not seen them get bigger than smaller. It should be smooth from cell to cell.

I have to ask why do u want to go open loop. I hope it is a summer car and you keep a wideband in it. I have a few friends that do it because they can. Not much to gain, but if you go lean it could hurt alot.

RevGTO

iTrader: (12)

I was getting constant 02 sensor codes with my LT's and tried all kinds of options with no satisfaction. I decided that if I could tune my AFR and MAF tables with the wideband I could get AFR where it needed to be and get rid of my 02's.

I've been running the car with the LM1 in it for a while and constantly adjusting the tune. I'm really getting close now, but I need to tune certain areas up and others down as I mentioned. If I get it right, I'll pull the WB until October or so and check my AFR then.

I realize the scale can only go one way - up - but wondered if a bigger jump in a couple of cells here and there would be a bad thing.

The only thing that has concerned me is that the car goes somewhat leaner when it gets really hot outside and the A/C is on. I haven't seen anything dangerous - 16.0 idle, 15.7 cruise is about as lean as it has gotten.

Right now typical readings (operating temp) are 15.1-6 idle, 14.4-15.1 cruising, 12.7 WOT on a commanded 12.5 PE. I'm shooting for 14.9-15.4 cruising and commanded=WB WOT.

2Tightwads

So what happens when your MAF takes a dump one day?

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Disable LTFT and log MAF vs STFT, try to stay in each cell long enough to get good data than copy/paste special multiply by %.

Then highlight the table and smooth between horizontal bounds.

If you do this a few times you should be able to get the maf table dialed in perfectly without any odd jumps or transitions in the table.

RevGTO

iTrader: (12)

That's a good approach - thanks. In the absence of this information, what I did was start over with the stock table and multiply it by a uniform percentage to values that I knew were close by my trial and error method. Then I adjusted the areas that needed it and smoothed the transitional cells manually by comparison of the percentage difference from stock. I'm getting very close now ... test drive and logging this afternoon will hopefully show me to be there.

I'd be running SD and fairly lean until I replaced it.