Now that I think I may have sorted my idle system out, I thought I would play around with Data Scan again.

Thought I would start with looking at how she was running with regards to fuelling.

I have attached a video showing the car at operating temperature in the dashboard display showing various values,

then I have switched to the fuel map display.

As I do not understand it myself, would you guys have a look and, firstly see if everything looks right, and secondly, would someone explain exactly what I am looking at please?

 

[video=youtube_share;K7vrEFwpTsI]

i think Noz is the man to answer this mate...

X-axis along the top: Load value from 8 to 88

Y-axis down the side: RPM value from 400 to 6400

 

Blue cells: O2 feedback enabled (closed loop mode). Subtract 192(decimal) to arrive at the fuel table value.

Red cells: No O2 feedback (open loop mode).

 

Yellow cells: Trace function showing which cells the ECU has accessed based on the load (MAF voltage) and RPM (CAS voltage).

Green cell is the cell being accessed by the ECU at that moment in time.

Edited April 14, 201312 yr by Noz

Well that's cleared that up then, thanks Noz:huh:

X-axis along the top: Load value from 8 to 88

Y-axis down the side: RPM value from 400 to 6400

 

Blue cells: O2 feedback enabled (closed loop mode). Subtract 192(decimal) to arrive at the fuel table value.

Red cells: No O2 feedback (open loop mode).

 

Yellow cells: Trace function showing which cells the ECU has accessed based on the load (MAF voltage) and RPM (CAS voltage).

Green cell is the cell being accessed by the ECU at that moment in time.

 

So Load = the injector load?

RPM is easy to understand

 

after that im lost, apart from the yellow cells, green cell lol

Scrambled my brain cells!

Load (engine load) is comparable to 'boost' or air intake. It is calculated from the voltage outputted by the MAF. It's actually called TP, Theoretical Pulsewidth.

 

On a stock ECU, when the TP/load hits a value of 127, it will hit "fuel cut". On most Nissans, this is at a much more sensible amount, and is akin to driving into a brick wall. On the Zed, for some reason it is waaaaaaaaaay beyond the scope of the stock maps (88 for fuel, 96 for timing).

 

As an aside, since the fuel map is here for all to see in a video, and you can get a good idea of how the ECU functions: the average JWT/70bhp chip have exactly the same load values along the top axis. When the MAF sees more air than the ECU is programmed for (i.e. over 88 for the fuelling map), it simply takes the value from the last cell and uses that. No extrapolation, just the last cell value it sees....

Cheers Noz,

Starting to understand it a little. My first thoughts are, after a short while idling. if I apply throttle suddenly, she looks as though see runs lean for a short time. Would this assessment be correct? Or am I worrying over nothing? my first thoughts are that I am getting air drawn in somewhere as there is a definite short hiss at the time of acceleration.

Cheers Noz,

Starting to understand it a little. My first thoughts are, after a short while idling. if I apply throttle suddenly, she looks as though see runs lean for a short time. Would this assessment be correct? Or am I worrying over nothing? my first thoughts are that I am getting air drawn in somewhere as there is a definite short hiss at the time of acceleration.

 

You need a wideband lambda sensor in order to determine if you're running lean or rich.

 

The only time when running lean is an issue (generally-speaking) is when on boost.

looks like online bingo to me

looks like online bingo to me

 

:lol: