Hi Sharif,

Actually it is this hand off that causes problems with the stock ECU. As we all know the Z, like many modern cars has on-board scaling that adjusts fuel trim, timing, and other parameters based on how the car is performing and what the ECU thinks is "correct". This "learn rate" is actually alterable in the stock ECU, just as how the OL/CL transition period can be changed. And it is this learn rate that often causes a viscious cycle to occur when a Utec is installed as where the Utec is controlling say injector pulse width and timing a certain way but where the ECU expects to see something different. The result is often closed-loop and low-load instability during the periods where the Utec is handing off control back to the stock ECU. Now clearly this would not be a problem if you're driving your car in OL all the time, but this scenario is far from ideal for your average street car as OL or speed-density (MAP only) configurations is never the most efficient setup. Therefore I stand by my comment that the Utec is not the ideal management solution for the Z car, especially one that is a heavily modified street car.

Cheers,

Gary
Gruppe-S

 

I am going to stop trying to explain this, becuase apparently, it is not coming through correctly. Maybe I am tired or something.

But there is no OFFSET occuring when you are in open loop fueling mode is enabled. You are SETTING the actual injector pulse widths.

King Tut, how many VQ35's have you tuned with the UTEC? It's very different from the other UTEC offerings for different cars.

 

I have tuned none, and I have never even used the UTEC software, however, I know how to read very well. I don't see what your problem is, but it seems as though you are attacking me while I am simply trying to get the proper information posted in this thread. The UTEC sets the injector pulse widths by using background fuel map based off the MAF voltage and the offset/percentage you put in each cell of the MAF tuning map. It's that simple. I don't know why you are so affraid of the word offset but that is how it works. Please see the attached image and read it fully:

 

it says that it will reduce the voltage that the computer sees and it will adjust the fuel accordingly.....

wtf!! hehehe i just know that my car runs weird sometimes with the utec open loop maf pulldown mode. i figure its the stock ecu doing something.

 

just bought an emanage blue pre-tuned to similar mods... gonna make some camcorder runs of rpm/afr before and after installing the emanage... wish me luck

 

King Tut.....Shariff know what the fluck he's talking about. You'll loose this argument, I highly doubt you have the real world experience Shariff has with UTEC's and 350Z's

 

Not to offend but the problem here is that you don't know what your talking about, what you have stated about the UTEC is not true.

 

Actually, we both made a couple oversteps...no worries. Everyone is still learning the UTEC. My experience base is much much stronger with FI cars on the UTEC. NA control of the engine via UTEC is a little bit different.