So I just got my UTEC tuned and dyno'd a whopping 306WHP (WOOHOOO). Head out to the roads to do some road tuning and I am running into a problem I never had before. I have been running 1.5 bar for boost for a long time but ever since the tune I am getting boost cut CEL's and fuel cut from the stock ECU during 4th gear pulls anywhere between 3800 and 6000 rpms. Searching here I found a post stating that around 280 to 310 WHP the MAF will be pulling in so much air that the stock ECU believes you are hitting boost cut because the wastegate cant vent it out properly. The ECU then does a fuel cut and throws the Overboost Condition code. Is there any merit in this statement? Anyway to have the UTEC raise this value? So far everything I have found says I need to send my ECU in for a re-flash. I would find it very disappointing if the UTEC cant fix this but the XEDE has no issues resolving this.

 

WTF utec can easily push back the fuel cut. Go to the parameters and probably in open loop fuel and change the fuel cut hz/

 

Are you getting only the code? or the symptoms too?

I too get this on occasion at part throttle, at least, it throws the code, but I get no symptoms of fuel/boost cut (I control timing boost, and fuel directly with the UTEC so utec actually doesnt care)

I'm not sure the UTEC OLF settings for fuel cut are relevent to passing information to the stock ECU, or are used for its own cutoff.. Hopefully turboXS can answer this, I am assuming its for the UTEC.

The issue is the annoying CEL for me, I also get another error for a bank1 rich because of the stock O2 sensor seeing a rich condition on my car just before boost ramps (its a portion of my map I haven't made much effort to tune at the moment)

Anyway, I think your solution may be in HOW you control your boost at the lower loads, the ECU may be seeing a more aggressive boost curve than before, and assuming its an overboost situation, I'm not sure how to resolve it other than setting the boost level in that area of the maps lower unless your at higher loads (60% duty in the 0% load column)

 

I am getting the symptoms as well =/
Its very jarring to say the least. I was able to get rid of the error though by simply dropping my boost from 22psi to 21psi.

I definitely build boost a lot quicker then before! Perfection Motorsports did one hell of a tune on my car! Its very very smooth insanely powerful at even %50 throttle.

So is stock boost cut normally at 22psi? I really could have sworn it was 24psi.

 

On my 03, stock boost cut is approximately 24 psi.

 

I think what is happening is while your still in closed loop fueling, your boost is ramping really quickly before you get out of that 10% column.. once the UTEC takes control (if your running the UTEC's OLF, and not the old style MAF offset control) the fuel cut/boost cut on the ECU is basically just an error code you will see on the ECU and you shouldnt get any symptoms...

The ONLY time I had gotten this to happen with boost/fuel cut symptoms was when the UTEC was in map 0 as I was logging, the airflow (MAF) reading would ramp much quicker when the car was closer to stock, so if I plotted the MAF/MAP readings and injector/AFR readings from before the mods and after, I'd get a very quick ramp of airflow after the intercooler/pipes/maf pipe, than before, so boost would spike at about 500rpm lower, right at that point, I'd get fuel cut, but the curve was slightly different so it would run rich, then lean as it ramps..

the 0% column you can turn down your boost duty (And/or use closed loop) so you never go over 19psi or so while in closed loop ECU control, that seemed to help on my car.. once I crossover into the UTEC OLF (35% tps) I can run whatever levels I like with no cut, however it will still occasionally throw the light..

 

Thanks for the feedback MJ.
I believe we have been doing everything in closed loop fueling right now. We are going to switch to OL today and go tune for a bit to see if we can get rid of the fuel cut. I tell you what, this car is amazing over 300whp.

 

This didnt make any difference. We raised it to 30 and the fuel cut still occurs.

 

The bottom line here is that the UTEC does not appear(I am no expert though I am experiencing the same aggravating problem as PDXEVO) to be able to do much to work around the factory ECU boost/fuel cut. With a piggyback system it seems as though a flash is necessary to get around this issue. On the Vishnu website the offer the Xedeflash for only $100(I suspect the low price because the flash is basically only there to deal with stuff that the XEDE cannot deal with). The explanation for the Xedeflash is: The XEDEFlash fills in the two small gaps left by our XEDE engine control computer: the boost and rev limits. It raises both limits to account for higher output applications. We also account for things like larger injectors within the XEDEFlash as well. If you’re an XEDE owner, ask us if the XEDEFlash is right for you.

I realize that the Xede and the UTEC are two different beasts but they are both piggyback systems and I suspect that this is one issue that they both share in common. I would not even post this information(as I am absolutely not an expert in this area) if anyone had posted a direct reply to your original post. I would be willing to bet you that no one from Turbo XS is going to come into this post and clear this matter up because it does not appear that there is an answer.

I really wish that TurboXS would furnish their certified installers with an ECU Flashing tool to eliminate the boost/fuel cut as I have read through hundreds of posts and all that I have heard is: turn down the boost(regardless of the fact that you are perfectly safe at 21-22 under many circumstances) or get a flash.

It just is a bummer to spend $1K plus on a system like UTEC and still require a flash to realize the potential of the device.

I would appreciate it if a few of you would reply indicating that I am an aboslute idiot, etc, etc and tell us how to get around this issue without a flash. It would make my month!

Good Luck PDXEVO

 

This is an absolutely incorrect assumption.. in Firmware prior to 1.7, you were altering the MAF signal, so at that point you would have been subject to a airflow related fuel cut and hard coded RPM limits.. However Timing and boost were always controlled entirely in the UTEC (no CAS offset or reproduction issues) In firmwares at 1.6 (1.7 was the first publicly available) you had Open Loop fueling, the injectors are now driven entirely by the UTEC and therefore **ARE NOT** subject to fuel cut, boost cut, or RPM limits set by the ECU after the the Open loop crossover point.

There are circumstances where you will occasionally get a CEL due to the ECU seeing a fuel cut condition, however the ECU has no control over the engine at that point and therefore will not affect your performance nor will you get symptoms of fuel cut. There is one rare exception, very very cold dense air where you may get a very rapid and high level of boost while still in closed loop control can trigger boost/fuel cut, however the way around that is to set your boost levels in the 0% column so they never go above 17psi when your in closed loop fuel control by the ECU.

 

MalibuJack,

Thank you for the thoughtful reply. I was actually hoping for someone to explain to me why my thoughts we off base. So as long as we are working with open loop fueling this issue should be eliminated when the engine is past the open loop crossover point?

In reading through this topic in other posts I can see that this has been addressed before. My bad!!

Thanks for the lesson.

Technov

 

That is correct, once your no longer in that 0% column, and you have the OLF features enabled, you are essentially running a standalone engine management. You can't beat the stock ECU for its ability to learn fuel trims, and part throttle low load driving and just allaround great drivability and adaptability to most driving conditions. The UTEC just makes things better by allowing you to take control over the portions of the ECU that most find to be a deficiency.

 

Hey Technov,

I need to go do some tuning in OL mode to see if the issue goes away or not. I guess dealing with a constant CEL light is better then dealing with a stall during power ramp. It should take to long to adjust everything back to OL from CL. Ill let you know how things go!

 

Sounds good. Today I had the GSC cams and UTEC ABC installed. Tonight Kelley is tuning the car with the ABC in OL mode so I'll also have an idea of how this is going to work tomorrow morning hopefully. You may have to go for a ride in it to feel the cams!

Take care,

Adam

 

No kidding! I am up for that! Ill be swinging by tonight after work Maybe Ill see you there!!