MadDog

I'm interested in how people are dealing with LTFT and the other undesirable effects of piggyback fuel management with their turbos. According to GReddy, the LTFT shouldn't come into play since the fuel is only adjusted under open-loop conditions. That makes sense, but there are some with the kit that would seem to disagree.

For those controlling with the eManage, have you witnessed the LTFT responding to the added fuel? I don't mind disconnecting the battery every once in a while if that's all it takes, but I want everything to be predictable. I already have a WB02 running to my profec e-01, just to keep an eye on things. i don't want any sudden surprises from the eManage/ECU combination while I'm driving and mash the gas.

Some folks seem to be getting good results from the eManage and others aren't. Any thoughts on LTFT or the use of a piggyback in general? ( I'll shoot anyone that says "the eManage is a POS" without any supporting data! )

rkostolni

Since the car is in open loop during boost thanks to one of the dongles, there shouldn't be any fuel trims. However, I think most people using the emanage do experience some, I would like to know how if anyone knows. But, Greddy runs the high rpms soo rich that it should be fine even if the ecu does trim some. But the ecu is definitely learning something. The car drives different after a while and definitely looses power over time until you reset the ecu by battery disconnection. If you want to go turbo, I would really recommend another fuel management option.

It seems our choices right now are the Megasquirt, emanage ultimate and the Interceptor, in order of pricing.

I would really like to see someone turbo'd try the Megasquirt or emanage ultimate. I know MazdaManiac is soon trying the emanage ultimate, which will provide some insight, but it would be nice if a Greddy owner tried it.

This would be a good place for a discussion of these various options for us who are going to go to a better system, and just can't decide what.

MadDog

Well, I have noticed that on the baseline GReddy map, the temp. dongle isn't activated until 10kPa while the injection maps start at 5kPa. So It looks to me like there is a little but of room where the ECU will read rich conditions prior to going into open loop. Maybe this is where the trims are coming from?

By the way, I installed my eManage, AFR sensor and the Profec e-01 last weekend and I'm doing the hardware this weekend. Driving around with the emanage set-up but without boost is a -GREAT- way to learn the system before getting into trouble. I've learned a lot about the system this way, and worked a few bugs out of the system in the process. Hopefully, things will go a little more smoothly when the turbine gets installed now. Doing it this way let me F some things-up without worrying about damaging the engine. I would recommend this to people doing a turbo install.

-MD

zoomzoom_8

I definetly experience LTFT during boost, have no idea how the ecu is doing it but it is. I can watch my a/f gauge under boost after running the emanage for a week or more and it goes lean under boost. Reset ecu and it is back rich under boost. I am definetly going to another fuel management solution other than emanage, just have not decided which one yet.

MadDog

You should call Benny at GReddy and ask him how this is possible. They claim its not. Maybe they don't fully understand it. That damn ECU is almost self-aware...

rkostolni

I remember MazdaManiac saying a while back that this car does not have a defined open/closed loop like most cars do, in is always inbetween the two. Not really sure what he means, but perhaps the inability to force it completely open loop shows this to be true.

Zoom, how lean do you A/F's get and how long once you reset until the ecu begins to adapt?

TORacing

there is undeniable evidence that LTFT still exists with Greddy owners which is why many are switching to the InterceptorX, the Ultimate Emanage r some other advanced EMS.

zoomzoom_8

Really Lean! like 16s and 17s, happens almost overnight! I constantly keep an eye on the a/f gauge now.

I disconnect the negative terminal on the battery, let it sit from a few minutes and connect it back, good to go, back rich again.

the first time, everything was cool until about two weeks ago, now I have reset twice in two weeks.

This ecu IS self aware. . like Cartman's trapper keeper on south park. I am scared to go into the garage sometimes late at night, it may just eat me for messing with it!

PUR NRG

Does anyone know what Keep Alive Memory (KAM) is or what it does? I know one of the later flashes expanded KAM functionality so there were some post-battery connection operations that were no longer necessary. I wonder if LTFT is one of them.
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adrian-1

I've got proof.
My car was dyno tuned alittle over a month ago (070705). The shop removed alot of fuel from the stock map and was able to keep increasing the power above 6k instead of it flatlining out like before. Here's that thread if you want more info.
The car pulled much better above 6k rpms. It was too rich before and the power dropped off which also affected the boost curve and dropped earlier. My boost would now stay around 5psi after 6k rpms instead of dropping down.

I had been resetting the battery every two weeks. The shop advised me to do this since they knew about the 8's ecu learning and changing the fuel trim. After the first reset, I did notice a slight increase but it wasn't as strong as the first week of having it tuned.

Last week, I had alot of backfiring and not just at cruising speeds. It backfired 6 times in a row and later on that drive, a CEL came on. Got home and checked it with my Canscan.
Code- P0172 System too rich (Bank 1)
I checked the emanage to make sure it had my tuned map loaded. I cleared the code and reset the battery. The backfiring went away.

Yesterday I made it out to San Antonio Raceway to see what kind of times I'd get after the tuning and other stuff (fixed boost leak, gapped plugs to 0.030).
I got a 14.0 and 13.9sec plus one 14.5 due to a bad launch. My previous best was a 14.0, so I didn't improve that much.

I recorded the Greddy E-01 graph and it shows I'm getting a boost spike of 6psi then dropping down to a constant 3psi after 6k rpms. I don't think it's a leak since it would drop even more if it was. I suspect the 8's computer to be the problem and I'll find out next month. I've put in an order for the Interceptor X EMS to replace my emanage.
Once I receive it, I will redyno with the current EMANAGE and see how "bad" my AFR's and hp/tq are. Then we'll install the Interceptor, dynotune it and compare.

I've also posted my dragstrip runs in the mutimedia section here.

Another note: I'm still using the stock boost, the E-01 boost settings are all zerod.

adrian-1

Here's the snapshots of the Canscan showing the LTFT and STFT before and after the battery reset. The 3rd is after a short drive. It goes back to what the LTFT was.
It does reset them but the car still doesn't seem as strong compared to the 1st week after tuning it.

r0tor

iTrader: (1)

Can you try tuning the system after running around on a very safe map without resetting the trims?

The reason LTFT were created was so the car could adjust to conditions as it aged - like air cleaners becomming more dirty, maf's becomming dirty, ignition system going downhill, ect. If your pulling a -21% off boost right after a reset, it would seem to me that even the non-boost area characteristics of the car are not even close to what computer considers normal - so you will have to let itself adjust things until it thinks that things are normal.

I mean from those 3 readings it looks like the thing is happy and settles at -21%. So why not tune with it at -21% rather then forcing it back to 0?

zoomzoom_8

or maybe the 30% max that it will take out, but it would be super rich while we were waiting for it to lean the mixture out. Or maybe let it do its ltft and then change the map and increase fuel by how much ever it took out, I dunno, may work, but I think I am just going to the ultimate or the interceptor real soon, this fuel trim is getting old!

DreamWarrior

I would rather reset it to zero rather than re-tune soley for the reason that sooner or later you'll have to change your battery and what are you going to do then? Change the battery and reload a really old map at the same time until the ECU "relearns" the LTFT?

cretinx

Celica GT-Ss used to do this with the S-AFC but not the e-Manage . . . . . weird.

So you're saying the car learns and compensates?

Xyntax

R flash here and this is what I noticed:
- Before driving for the long trip (4 hours), my LTFT was consistently at -5% for idle and some ranges.
- After the trip, it went to -3%
- Unplugged the battery and plugged back before taking the trip back home (4 hours). My LTFT was consistently at -8%
- The day after, it was still at -8%.
- A week later, I checked, and it was at -3%

...During that -8% phase, my car was running so much faster ever at all rpm ranges. Now, it drives like it used to, but with more throttle response. What do you think is going on there?

r0tor

iTrader: (1)

I'd rather worry about the 99% of my daily driving and not the 1 time in 3 years I have to change the battery.

r0tor

iTrader: (1)

First off, anything I say its just educated speculation...

From what I have read, the LTFT are basically like a grid in the greddy - different buckets to store adjustments in for load/rpm combinations. In closed look it is continually tweaking the adjustments trying to zero in to the point where no more adjustments are necessary. The longer you are in a particular area, the quicker it will adjust that area - but based on those adjustments it can also make an educated guess at other areas in the map and adjust them as well at the same time.

Think of it like a basic temperature control valve. You put in a temp setpoint, the valve opens/closes depending on what in needs to do - but almost always it will overshoot slightly, then undershoot more slightly, then overshoot a touch, ect until it finally stabilizes at its setpoint.


Just have to give it some time to settle.

zoomzoom_8

yea, may be true, but the bad thing is that the ecu is smart enough to take fuel away from the emanage under boost thinking that something is wrong with so much fuel and not knowing that boost exists but then it is dumb enough to not know that the car is running dangersouly lean and adding fuel back. It just senses a knock, retards the timing and continues to take fuel!

zoomzoom_8

mine got so bad that anytime boost came on the car stalled before I realized what was going on!

zoom44

dangerously lean as far as the turbo is concerned you mean? becuase it can defintely tell when it is too lean for its normal NA stock form.

zoomzoom_8

Yea, thats what I meant, too lean under boost, but you know, looks like the stock ecu could at least sense the a/fs are lean and re-add fuel it took it away in the first place. maybe throw a cell or something cause it could not figure out why it had to add fuel (cause of boost) but add the fuel. At this point, we could only pray that it would be that easy. Can we say standalone or interceptor?

PUR NRG

How so? The stock ECU is receiving conflicting information regarding how the engine should behave.

According to its programming it wants to maintain AFR around 13 or so. A boosted car should average 11.5 AFR. Therefore the stock ECU detects it's too rich and leans it out. By doing so the engine knocks so it temporarily retards timing and takes some fuel away. That cures the knock but then you're running too rich again and the cycle repeats.
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zoom44

bingo

zoomzoom_8

yea, but on my first go around before I knew what was going on with the ltft, the stock ecu had me running about 14.6 under boost! 13 would have been so much better! I was just saying it would be nice if the stock ecu would take fuel away, the engines knocks and the ecu says well, don't know why it did that, but here is so more fuel and let it be. Just wishing though, i am saving up for the interceptor, sick of the stock ecu.