I'm have being speaking with different tuners, and all of the says that the ECU only makes adjustements when it runs in closed loop mode, and that is when the car runs on low load and below 3500rpm +/-.

They also said that there is no adjustement made (learn) at WOT, because the ECU at WOT doesn't use the lambda sensors...it's all of this true? if this is true why are not recomended the piggybacks?

Another point is, if at WOT the ECU doesn't use the autolearning feature, why when you make a reset you feel diference in power?

 

This is all specific to the EMS that you are discussing. What EMS are you looking at using?

The Pro-EFI I just had installed will automatically adjust for a lot of different things. Search the site for that name and you'll see more details in other threads.

 

I'm talking about the stock ECU and the use of a piggyback with it.

 

I reflashed my ecu with Orisis so it would stop trying to adjust around my UTEC tune. Orisis locks the ecu to one of five maps that can be toggled manually. Car runs much more consistently now.

Without the flash the ecu randomly switched it's own internal maps and tried to 'auto learn' around my UTEC tune. Totally annoying.

 

With the MAP sensor, when you're in boost doesn't the UTEC control the injectors. How does the factory ECU change these settings when they are programmed into the UTEC?

 

Yeah~ When the Open Loop threshold is passed (usually 25%TPS and 2,000RPMs), UTEC does have full control of timing and fuel. But keep in mind UTEC is basing it's fuel offsets from it's ECU interpolation for MAF, hence the term "Piggyback". If the ECU is trying to adjust around the UTEC in MAF mode, then the UTEC offsets will be off.

I believe MAP tuning is independent of the ecu though. Hopefully someone can validate that statement...

 

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Yeah, for the F/I guys using MAP, the UTEC completely takes over in open loop (when in boost). Low load though it's piggy back style.

 

For the FI guys this won't be problem b/c the fuel is adjusted based on the MAP sensor. But I guess NA guys with the UTEC need to worry about this.

 

Actually, it doesn't matter if you're FI or NA. NA guys running a MAP tune won't need to worry about it either. I believe I8acobra is running MAP on his NA setup. Maybe you could PM him for details. I chose to reflash my ECU to get around the problem.

 

I think that even using MAF as reference with the UTEC you don't have to worry about any correction, BlackTuner confirmed that, always that you select the Open Loop mode in the UTEC parameters section.

Anyway my question was if there is really any correction made by the stock ECU at WOT

 

If you try to run Open Loop 100% of the time, you'll be in for a very harsh/jerky ride (I know cause I tried it). Most people run a Closed loop/ Open Loop combo for this reason.

Just got off the phone with TXS. In MAF Mode, the ECU still controls injector pulse width, and that is what UTEC bases it's fuel offsets from. The ECU does actually try to 'correct' back to the factory AFR values in MAF mode (but UTEC is still able to retain full control over Timing). This 'correction' process does take the ECU a good amount of time/ miles to 'learn' around the UTEC tune though.

I was also able to confirm with TXS that in MAP mode, the UTEC does have full control of both fuel & timing in Open Loop. The ECU is completely out of the picture here.

So to this end, an ecu reflash or MAP tune will alleviate the problem. If you are NA and wish to tune to MAP, you'll need a MAP sensor. If you're MAF tuned, you'll need an ECU reflash to compliment it.

Yeah, expensive hobbie we have here. Lol.

 

Yea gothchick, this is an expensive hobbie!!!!

Look at this post of BlackTuner, and you will see that you can have full control of fuel with the UTEC https://my350z.com/forum/showpost.ph...4&postcount=10

Anyway, the question was, if it's real that the stock ECU makes compensations at WOT? If that's real, why are cars that run rich and others lean?

If the stock ECU doesn't makes corrections at WOT, then a piggyback won't be so bad, isn't it?

 

Hmmm, I'll have to let BlackTuner elaborate more on that thread then... There may be subtle differences between year-models of ECU.

For instance, UTEC can change the redline on '03~'04, but can't change it on '05~'06 rev-ups. Maybe that same kind of dynamic is at play here as to how much control the UTEC actually has in MAF. Another difference may be the version of UTEC firmware that is running.

I know for my '06 rev-up, I couldn't hold a stable MAF (fuel - AFR) tune for more than a month or so with UTEC v2.8d. It would gradually run crappier and crappier, until it finally ran like ****. Resetting the ECU would temporarily solve the problem, until it started learning around my UTEC tune again. Very frustrating.

So, per Jeremy @ PF's advice, I reflashed the ECU... Then tuned using the re-flashed ECU as a reference point. Bingo - seven months later and it's still running like the day I tuned it (minus slight variations due to ambient temps - Winter vs. Summer).

UTEC isn't so great at Global Temp Compensations, so I've created several seasonal maps that can be switched manually.

 

Well, the problem with the limiter is that the rev-ups have a soft limiter, closing the throttle body plate when it is reached, so, with UTEC, you can change the limiter because the UTEC doesn't control the DBW system.

I don't have that problem (I think). I have variances in the AFR, but they are due the temperature changes.

If you take the page 32 from the UTEC manual, in the definition of Open Loop Fuelling, you can read...

...Whe Open Loop Fuelling is enabled, the UTEC uses its own background fuel table to determine injector on-time instead of the factory ECU's fuel table once the car is past the Open Loop Threshold parameter setting. This allows the UTEC to drive the injectors completely independent from the factory ECU.

Yea, that is the best option, but also the most expensive

UTEC is very bad in temperature compensations you can see a lot of change in your AFR in 10ºC. I think that it should interpolate