KingTal0n

it depends on the engine management. Some factory computers are three or four times more technical than any stand-alone and can be tuned precisely so that in open loop the vehicle performs extremely well. It also depends on experience of the tuner and accessibility. Some computers like Power-FC have hand-held units which make spot adjustments (for those rare days of weather) easy. If the ECU is difficult to access, involves some kind of non-real time tuning process, etc... then of course it makes sense to keep the closed loop.

nor11384

iTrader: (1)

Thank you for all the info. Finally some action in the thread. Ok so yes it is the dreaded lean tip in. I’ve added fuel in the accelerator enrich tables and it’s weird because it will work but it’s random. For example I’ll take off and it’ll hit 17afr. Then I’ll take off again and at the same kpa around the same rpm it will hit 14.7 - 15. Now, I’m on stock injectors. As far as I understand, the latencies should not be touched.I will try and take a log for you guys. I believe I have one from the other day but idk how good it will be. I’ll post it any way.

* one thing I tried and seemed to work was adding ve and in the maf comp table pulling fuel around idle to try and keep it from being too rich. I’m idling around 13.4 now. Here is 2 logs. I will have to take new ones because on these i added accel enrich like crazy to try and mask the issue. I beleive youll still see some 18afr here in the while taking off.

Evo9_Dubai

Please log o2 sensor to make sure voltage is within range.
Also, try reflashing a completely stock sd rom and see if the problem persists. Was the car tuned before or after the S2 cams?

nor11384

iTrader: (1)

I’m not using o2 sensor. I’m in open loop. Car was tuned before and after cams by me. Car runs perfectly fine except this issue. I have tried using 9653 and it has the same issue so it’s not the rom.

nor11384

iTrader: (1)

Ok guys I’ve been messing with it and the issue is a lot better. Now if you blip the gas at idle it’ll go rich instead of lean. My main issue here is that cruising it is rich. 13.1 - 13.4. I had to add ve 60 - 90 kpa because it helps with lean take off issue but now how in the hell do I lean out cruise without affecting these areas? I mean, if I wouldn’t be having the lean take off issue my instinct would be to pull ve around 60 - 90 kpa because that’s where we cruise.

KingTal0n

You've got to get or figure out how much resolution the map offers between transitions and steady states.

For example, for these basic ranges (made these numbers up for this example):
1. 50mph cruise range 15-16" Hg (45-50KPA)
2. 60mph cruise range 14-15" Hg (50-55KPA)
3. 70mph cruise range 13-14" Hg (55-60KPA)

ex
In range 1, around 50mph, the engine steady state vacuum is say 45KPA. It fluctuates down and up a little bit, 43, 44, 45, 46, 47 so that is our range for steady cruise.
If you hit a hill it will drop to 47, 48, 48, 50KPA (new range, no longer steady state)
So even though you consider hills "cruising" they are technically transitional. Some cars have significant variance between steady and transitional situations, which is why logging and reviewing is necessary to gain insight.

In range 1, if you take it one step further than "going uphill" to a "mild part throttle acceleration" the KPA range would be even higher, say 52-55KPA
So the a/f ratio for steady cruise could have been 15:1
going uphill at 14.7
And slight enrichment for part throttle acceleration (13.8~)

Even though they all fall within the range of 45-55KPA a "cruise range" you want to fatten up the regions for that RPM (MPH for locked trans/manual) where the vacuum dips into part throttle acceleration regions near the same KPA.
What this boils down as a worst case scenario to is a resolution conflict, if you cannot alter the map to tune these regions separately. For example in AEM, MS, Haltech ecu, you can alter the graph to provide each KPA value where it needs fine tuning separately.

How to use this data without high resolution fuel maps
There is a technique I call "checkerboard hypothesis" whereby I cause certain cruise cells at lower speeds (lower rpm) to be slightly leaner than near-transitional cells at higher MPH(rpm) and then blend between them.
For example, if these are cells [ ]
rpm increasing to the right ->
VE table
[45][48][50][52][55][58][60]
[43][46][49][50][53][56][58]
[41][44][47][48][51][54][55]

That is something 'appealing to the eye' you might see, all the values 'make sense'. However it may be inadequate because basic variations in sensors, temperatures, and map resolution.
I colored the cell orange to simulate a range for cruising vacuum, notice vacuum drops as speed increases to the right, so you can see how I "checkerboard" a solution next,

[45][48][50][53][51][59][60]
[43][45][51][46][50][57][58]
[41][43][47][47][49][54][55]

SO here is the same map, checkerboarded up. The basic idea is to understand that the ECU does not use 1 single cell at a time for it's VE injector spray. Instead, it uses a combination of all nearby cells.
It is very rare to cruise or stay steady state in 1 cell for extended periods. Even with cruise control, variations in the road cause the cell to drift left and right, up and down all the time.
What we have done is allowed the cells to "pass through the region" of reduced fueling for cruise situations (say the 46 represents a 15.5:1 air fuel ratio for example) but since it won't STAY there for very long, it will constantly be mixing in with the nearby values which as you can see have been increased in the fringes of the cruise situation to slightly richers values which will compensate but only for a limited period of time before the cell moves away again and the a/f swings one way or the other. In a way this is a "closed loop" effect for open loop maps, i.e. it will create an A/F pattern on the Gauge which gradually swings from 14.7's to 15.5's for cruising and still gives enough fuel (adequate transitional fuel as you can see to the right and top) when the engine begins to fringe into the cells where the engine is accelerating mildy.

nor11384

iTrader: (1)

I get what youre saying and maybe if i was using the 3d version itd be easier to tune it out. Here is a log of last night me cruising at around 80 - 100 mph or so on the highway. Kpa goes from 55 - 90 depending on rpms. I upped map ve in these areas to help with the lean take off. You can see how rich it is cruising. in the day time cruising at the same speeds it was 13.2 - 13.8 afrs. At night time which is this log it is richer. some spots it even saw 12.8 afr. I guess this is a result of being inopen loop. Cooler temps cause richer mix. Now, what would be the best way to lean out the cruise areas if i want to leave map ve where it is? Should i use the afr map? I thought about maf comp but it will mess with other things and it will only complicate things. Im thinking of just starting from scratch on the tune.

*Will also attach my rom.

KingTal0n

Define limits.
At some speed/rpm/load there are cutoffs. At 90mph you are no longer 'cruising' even if engine speed is not increasing, if KPA is high enough to upset compression ratio in a heating combustion chamber.
In other words, with some engine/transmission combos, at 90MPH in overdrive can be high enough rpm and enough load to require more fuel than 14.7:1
Especially is map is higher than 75KPA with 10:1 and more compression using gasoline.
You have to use some common sense. When RPM or LOAD is high beyond a certain point (define your own limit) you don't want the engine in a fragile state, i.e. 14.7:1 or close to it. Just in case.
because at high RPM or high LOAD things can change quickly.

In 4-cylinder 2.0L application 9:1 compression I think 75-80kpa s okay 14.7:1
if everything is clean (no oil/normal carbon)
Also RPM can be a factor. After say 2800rpm that is no longer really a 'cruise' rpm I am comfortable with.
"cruise" is usually defined with limited below that KPA and RPM value

1. I don't have your software so I cant see any logs
2. I never tuned that software so I dont know how it is 'normally' tuned'
3. Generally the tuning is done to the VE map first, while MAF is disabled. This from other platforms that use both I am familiar with.
Some computers have PE mode, enrichment modes, which ask that the VE table be tuned to 14.7:1,
whereas most stand-alones have no such mode, and the tuning for higher load is done directly in the VE map (my preference)

Overall the way its done can vary dramatically. For example in Power FC application I tune the global injector constants and delay times first, while driving,
Then spot tune the VE,
Then adjust global MAP constants (if not using a laptop)
Then finalize in the VE map

maybe (hopefully) somebody who has tuned using your exact software/engine can comment on an easier way to progress.
Whereas I typically find my own path (rarely doing things 'everybody elses way' can be common once you get some experience)