ECU Load cap shattered!

[Realgib3]

Originally Posted by djuosnteisn I don't think you were have the calc load capping issue... So i don't think this will fix your afr's. My best guess for your situation would be that your maf table is too low in the higher g/s values (higher volts). Check out where your lean on your logs (while logging maf volts) and adjust the maf table up in that area. You may also want to play with your OL PT fuel tables and transition delays.

Yep all you should need to do is raise your MAF up top BUT, when you do that, you will see your calc load go up... which could bring you into the clipping zone.. which would then make it so you need this fix.

This is the exact chain of events that really brought this about. We raised our MAF's more, and more and more to combat lean AFR's but then nothing happened... hence the "car was acting a fool" thread.

[manelscout4life]

i never really messed with my mafs because dont people get less boost after adjusting them?
my ltfts are always pretty close to 0 as well

[AFcadet]

Just an update for how my car is reacting to it...

So far so good. After I first bumped it down 5% I was getting a peak calc load of 190. So I bumped it down another 5%...and now Im seeing a peak of 177. Fuel is holding perfectly at 11.3 now. So I am going to try to use this MAF table (-10% OTS...stage 2 SF + FMIC 93 oct).

I bumped up fuel .3...so I should be now seeing 11.6 AFR at WOT...and I bumped up load .05 in the upper RPMs because Im peaking at about 18.5 psi tapering to 16.8. And I want to be more around mid/upper 19 psi tapering to 17.5-18 psi. Ill have to monitor load and make sure I stay in the 180s and not bump up into the 190s and run into load clipping again.

If I get to close to 190...Ill have to take off another 5% of MAF to be a total of -15%.

I was also getting .35 and a flash of .7 of knock during my WOT runs @ 11.3 AFR...so I bumped up the Ign OL tables one block...and the ign tables at 1.94 are now lined up with 1.75

I know you all have already made these discoveries and had it work on your car...so Im not trying to take credit for finding the solution...but I thought I'd keep you posted on how my car is reacting to confirm that all this shit is working...and triple/quadruple check that this is a universal fix...and not a fix for just your car.

[Dano]

Originally Posted by AFcadet Just an update for how my car is reacting to it... So far so good. After I first bumped it down 5% I was getting a peak calc load of 190. So I bumped it down another 5%...and now Im seeing a peak of 177. Fuel is holding perfectly at 11.3 now. So I am going to try to use this MAF table (-10% OTS...stage 2 SF + FMIC 93 oct). I bumped up fuel .3...so I should be now seeing 11.6 AFR at WOT...and I bumped up load .05 in the upper RPMs because Im peaking at about 18.5 psi tapering to 16.8. And I want to be more around mid/upper 19 psi tapering to 17.5-18 psi. Ill have to monitor load and make sure I stay in the 180s and not bump up into the 190s and run into load clipping again. If I get to close to 190...Ill have to take off another 5% of MAF to be a total of -15%. I was also getting .35 and a flash of .7 of knock during my WOT runs @ 11.3 AFR...so I bumped up the Ign OL tables one block...and the ign tables at 1.94 are now lined up with 1.75 I know you all have already made these discoveries and had it work on your car...so Im not trying to take credit for finding the solution...but I thought I'd keep you posted on how my car is reacting to confirm that all this shit is working...and triple/quadruple check that this is a universal fix...and not a fix for just your car.

Great info AF!!!

it looks like you have your issues resolved and all you need to do now is polish it off a bit.

Keep in mind that as the weather warms up your Calc load will drop so I am targeting to stay right at the cap for my load.

Some speculate that a KR of <1 is just the ECU trying to fine MBT [VE effency crap] and can be safely ignored.

[fjames]

Originally Posted by manelscout4life wow i didnt even see that your right though thats definitely not good. it appears that the the flat shift to 4 did that o well no more flat shifts till I can richen that up a bit.

Your pedal position is weird in 4th, so look into that before you do anything. It's always been 99.x to my memory when WOT, and yours is 95.x. It looks like you think it's floored since it's holding an exact number, but it should be higher. If you didn't have it floored on purpose, then you can't really compare AFR to 3rd. Yeah, it's high for that boost, but it could have been following your map for all you know, since you're not at WOT apparently.

Originally Posted by AFcadet I know you all have already made these discoveries and had it work on your car...so Im not trying to take credit for finding the solution...but I thought I'd keep you posted on how my car is reacting to confirm that all this shit is working...and triple/quadruple check that this is a universal fix...and not a fix for just your car.

Keep it up man, you're doing us all a favor, applying the theory to a real-world tune.

[djuosnteisn]

I'm not sure you even need to "undo" this fix as the weather warms up. Yeah your load will drop some, but that would happen even if the fix wasn't needed.

Only time you should have to adjust anything is if you decided to further up the boost, or further mod the car, thus pushing you back into the clip zone.

But as i see it, this is a one time adjustment.

[Smoker6]

Well I paid extra attention to load on my way home and my DH was showing me hitting and holding 230 (tapering off towards redline to mimic torque curve) which matches my requested load. I suppose this may do nothing for me. My AFR's are a solid 11.8 dropping to 11.4 by redline, also no issues.

This was just me watching the dashhawk, so I'll take some actual logs on the weekend to see if I even need to bother with this.

[djuosnteisn]

yeah supers load cap was right around 240 IIRC.


You should up the boost so you have an excuse to do this, lol.

[Smoker6]

I'm already at 21.5psi. :O And yeah I have an '06 so perhaps mine is at 240 as well.

[superskaterxes]

heres my first log from the dyno, you can CLEARLY see that the load is pegged but im also not closing my throttle

[JmkC]

i do have one question and something strikes me as odd. i get the closed loop max load tables. but doesnt changing the closed loop max throttle table to higher values, make the car stay in closed loop longer, wouldnt lower values be better?

[Lex]

Super, is that knock that pulled 2 degrees from your timing or something else?

[djuosnteisn]

Originally Posted by JmkC i do have one question and something strikes me as odd. i get the closed loop max load tables. but doesnt changing the closed loop max throttle table to higher values, make the car stay in closed loop longer, wouldnt lower values be better?

You have to force the car's CL -> OL transition to be based solely on load to avoid any issue with lean or rich afr's.

[Realgib3]

Originally Posted by JmkC i do have one question and something strikes me as odd. i get the closed loop max load tables. but doesnt changing the closed loop max throttle table to higher values, make the car stay in closed loop longer, wouldnt lower values be better?

nope all it does is make the transition strictly based on load, rather than pedal position, rpm, or anything else...


Again though guys, this information is all over in the links I posted...

Originally Posted by superskaterxes heres my first log from the dyno, you can CLEARLY see that the load is pegged but im also not closing my throttle

I can only speculate on this, but I would have to say that although your throttle is not closing, it may still not be open as far as it could be, because as soon as your calc load stops rising, your throttle is also going to stop opening, as your throttle position is a product of your load calculation.

Also, on this log, were your DBW tables set to 100? or 80?

And now is when we need you to do this fix... and turn up the boost, and see what kind of power you can make

[AFcadet]

Alright...looks like a final update for me. I am pretty much one flash away from having my car identical to previously when it comes to AFR and boost.

I just have to tweak my fuel tables a little bit. After I bumped up my fuel by .3...I now have a very slight taper which looks like this....12, 12, 12, 12, 11.9, 11.9, 11.9, 11.9, 11.8, 11.8, 11.8.

Im going to bump the 12 AFR RPM areas down by .2, and the 11.9 RPM areas down by .1...and I should have a flat 11.8 (11.76) actual AFR line.

Boost is basically exactly where I want it. Peak boost of 19.5 @ 4700 RPM...tapering down to 17.5 psi.

Now here is the great part...My Calc load is peaking at 185 on this new map...where before on the same boost...it was maxed out at 195.

Also...I got no KR on any of my pulls...which Im sure it was because I bumped the timing tables up one box.

I may bump up boost @ redline to 18 psi...but my calc load will still be quiet low since it tapers down alot after 5000 RPM.

Only thing that confuses me a little bit...is my throttle position closing a bit after 5500 rpm. It goes from 75.66 @ 5500...and tapers down to 73 @ 6000. Not sure why...but its kind of the least of my worries at this point. Gotta tweak other stuff first.

[NJSPEED3]

Looks like my calculated load clips at 210! 2 secs after going wot

[GQ_WhiteMS3]

My AP is gone and I'm back to stock prepping to sell the car ... but I just had a question regarding this. What does playing with the MAF tables do to the stft and ltft's? Does it throw them all out of whack?

[superskaterxes]

Originally Posted by Lex Super, is that knock that pulled 2 degrees from your timing or something else?

no, i only had like .7 knock on that run and all of my logs have this wierd timing dump at that same rpm. i obvi cant see the map so i dunno if its something he put in there. max timing at RL is also like 7-8 deg below stock values

Originally Posted by Realgib3 nope all it does is make the transition strictly based on load, rather than pedal position, rpm, or anything else... Again though guys, this information is all over in the links I posted... I can only speculate on this, but I would have to say that although your throttle is not closing, it may still not be open as far as it could be, because as soon as your calc load stops rising, your throttle is also going to stop opening, as your throttle position is a product of your load calculation. Also, on this log, were your DBW tables set to 100? or 80? And now is when we need you to do this fix... and turn up the boost, and see what kind of power you can make

lol my clalc load never stops rising, BT bitch haha. i dont really know if that was 80 or 100 but im gona assume 100.

we will know thursday if the fix works for BT. im hoping but not getting my hopes up.

[bioevolve]

I'm nowhere near the load you guys are talking about. I'm on stock turbo thou.
Why is there such a big load difference on a big turbo when the power is close in the same?
Here is my log on a pull this morning.


datalog10.csv

[Realgib3]

Originally Posted by GQ_WhiteMS3 My AP is gone and I'm back to stock prepping to sell the car ... but I just had a question regarding this. What does playing with the MAF tables do to the stft and ltft's? Does it throw them all out of whack?

Fuel trims are only used during CL, so no it does not affect them.

Originally Posted by bioevolve I'm nowhere near the load you guys are talking about. I'm on stock turbo thou. Why is there such a big load difference on a big turbo when the power is close in the same? Here is my log on a pull this morning. datalog10.csv

Hmmmm you got some weird stuff goin on in this log.

1) It looks like you might be stuck in CL for a LONG time till about 4800rpm @ WOT
2) Your AFR's are kinda all over the place... and idk why
3) You're keeping the boost pretty steady... but your Timing Advance is jumping all over...

Lastly, what is your MAF curve peaking at?

Again, the mods/turbo you have, and the amount of power you are putting down DOES NOT have anything to do with your load being clipped. The higher your MAF values are, the easier you will hit the load clipping area. It's all in the calculation, NOT in your power level.

[JmkC]

i hit 232 right now and its cold out

[Dano]

Originally Posted by GQ_WhiteMS3 My AP is gone and I'm back to stock prepping to sell the car ... but I just had a question regarding this. What does playing with the MAF tables do to the stft and ltft's? Does it throw them all out of whack?

We are only changing MAF above the voltage WE set to enter OL. no fuel trimming goes on up there. In a log this point is where LTFT and STFT go 0.

I think its outlined in the doc

[Cataphract_40]

any hypotheses on WHY this 'wall' is encoded into the ECU?

mazda usa just trying to rain on our parade yet again?

[Lex]

There is a slight correction - if your maf is calibrated correctly, load should mimic torque at the motor.

I have been wondering myself why put this load cap. It is below all fuel cuts on the stock car. I wonder if it's there to prevent the fuel system from being overtaxed, or to prevent "tuning" the car with bolt ons, or simply mandated by the EPA that the car should not fuel any more than a certain amount to meet emissions.

[Realgib3]

Mazda was having a well documented issue with people complaining of sputtering and stuff at WOT. They ended up replacing a lot of HPFP's. And Lex you are exactly right, this was put in place for that reason, to save some fuel pumps.

[AFcadet]

Originally Posted by GQ_WhiteMS3 My AP is gone and I'm back to stock prepping to sell the car ... but I just had a question regarding this. What does playing with the MAF tables do to the stft and ltft's? Does it throw them all out of whack?

No...because right when the ECU hits that big dip in the MAF curve (around 3.6v), is @ 1.1 load... which is when we switch over to OL (and we changed the CL max load to 1.1). And in OL...fuel trims are ignored and it only goes by the MAF.

[Dano]

Originally Posted by Lex There is a slight correction - if your maf is calibrated correctly, load should mimic torque at the motor. I have been wondering myself why put this load cap. It is below all fuel cuts on the stock car. I wonder if it's there to prevent the fuel system from being overtaxed, or to prevent "tuning" the car with bolt ons, or simply mandated by the EPA that the car should not fuel any more than a certain amount to meet emissions.

slightly off topic here or maybe only premature, but is it true that even if this MAF scaling works, and Super indicated that the Cobb tuners use this method when needed, we still have a fueling issue with BT motors due to lower than needed fuel rail pressure and/or injector timing? In essence we are still "capped" at a certain g/s airflow into the motor by fueling limitations?

And further, this is why DJ made his little ckt CDFP pressure scaling device and does this get us a little further along?

[AFcadet]

Not sure...when I hear fueling problems with big turbos...its due to injector problems because of lack of pressure...not volume. I think our upgraded internals have enough volume being pumped...its just turning up the pressure (our ECU limits pressure by re-routing fuel from the fuel rail back to the CDFP)

My only question...is big turbos will be able to put down A LOT more load. So will they turn down the MAF by something like 40%? That seems excessive...and I wonder if it would still work.

[Fobio]

Originally Posted by AFcadet My only question...is big turbos will be able to put down A LOT more load. So will they turn down the MAF by something like 40%? That seems excessive...and I wonder if it would still work.

I think there will be only so much room to scale at this end before we run into another limit at the fueling end, like fuel rail pressure?

I'd think that PTP's fuel rail valve will be coming at just the right time. Unless of course, we can have better control of fueling thru the ECU instead...

is Christian setting up a new shop?

[m4tic]

are there any issues with the 2-3 shift studder with this? (or is it gone with the ap)

[SpeedSixxx]

yea why is that? when I shift from 1 to 2 or 2 to 3 the car stutters? no power then BAM didggity niggity..gone./..???

[AFcadet]

i never had a stutter...

[Dano]

that vid in your sig makes me studder....

[Docnox]

Originally Posted by SpeedSixxx yea why is that? when I shift from 1 to 2 or 2 to 3 the car stutters? no power then BAM didggity niggity..gone./..???

What are your mods? Happens to me going 2 to 3. I think it's boost cut. Vroooom, shift, spike, cut, VRROOOMm. Stop double clutching and just Paul Walker it in and it might drive better.

[bioevolve]

Originally Posted by Realgib3 Fuel trims are only used during CL, so no it does not affect them. Hmmmm you got some weird stuff goin on in this log. 1) It looks like you might be stuck in CL for a LONG time till about 4800rpm @ WOT 2) Your AFR's are kinda all over the place... and idk why 3) You're keeping the boost pretty steady... but your Timing Advance is jumping all over... Lastly, what is your MAF curve peaking at? Again, the mods/turbo you have, and the amount of power you are putting down DOES NOT have anything to do with your load being clipped. The higher your MAF values are, the easier you will hit the load clipping area. It's all in the calculation, NOT in your power level.

Here is another log with MAF:

datalog1.csv

[FORZDA 1]

Originally Posted by Realgib3 Fuel trims are only used during CL, so no it does not affect them........ 1) It looks like you might be stuck in CL for a LONG time till about 4800rpm @ WOT ..........

Yeah, I've been trying to explain to some dude "matsuda" in another thread that the LTFT is dropped in OL and that is your ONLY true indicator of OL, but he just refused to accept it.

Anyway, I reviewed the last log posted to see if I could determine the CL/OL delay timing and it matches up quite nicely. I used the STFT zeroing out as the start of "WOT" which is likely what the ECU triggers from rather than pure TPS as well. The stock map has the CL Exit delay A set at "30" which equates to ~3 seconds in that log. I have mine set to 15 which would be ~1.5 sec and it fits nicely as well. I would assume the stock map value of "80" for CL Exit B & C would be 8 seconds to keep the ECU in CL possibly for TCS/DSC action or some other emissions testing reason?

I have mine set to 15 (1.5 sec?) and 30 (3.0 sec?) respectively and I go into OL right after I step on the gas and look up at the DH fuel trims screen. I haven't logged it because I usually don't log STFT, but I'll check it out.

Just another point of data on ECU operation.....

[superskaterxes]

i never get the 2-3 studder when i FFS. i think it has to do with FP recovering

[ATE BALLER]

So, if it were possible to raise the calculated load cap up to whatever, or even eliminate it, would that theoretically solve this problem all together?

[Realgib3]

Originally Posted by ATE BALLER So, if it were possible to raise the calculated load cap up to whatever, or even eliminate it, would that theoretically solve this problem all together?

Yep, problem is we can't, at least not right now, so we just stay under it to solve the problem just as well.

[FORZDA 1]

Originally Posted by superskaterxes i never get the 2-3 studder when i FFS. i think it has to do with FP recovering

All you guys with this studder on shifting try this: Using AP, raise your normal rev limiter to..., say at least 7k rpms and try again. It seemed to fix my occasional high rpm shift studder with simply raising it to 7k.

If you don't have an AP, try shifting about 300 rpms lower...