Fuel Consumption and ECU tuning

[R24]

Hi Everyone,

 

I have recently got my ECU tuned and everything is working fine. There were some idling problem at start but got rectified when I increased the values in the Idle Target table.

My fuel consumption also seems a bit high even though I am not boosting and driving hard. I have a few questions to ask the tuners here to take a look into my base map and log to see what else can be fine tuned just to get a second opinion. I'm a newbie to aftermarket ECU tuning. Tips and suggestion from you guys are highly appreciated.

 

1. My Idle target is set to 880 rpm once the engine coolant reaches 70 degrees above (see picture) but the engine idles at 900 rpm above. Is this normal?

2. My throttle body has been modified to run mechanically without fly by wire function and I am using and external idle valve to control idle. How much do I need to open the butterfly valve gap when the car is off/idling?

3. Currently the overrun fuel cut is set to off when the throttle is released during cruising. Does this function effect the fuel consumption?

 

Best Regards,

 

Ragupathy

 

Log 2017-02-19 1;53;16 am.llg

IdleBaseIdleTarget.docx

[Adamw]

Can you post your .pclr also.

 

Looking at your log your idle control is in open loop mode.  That means the Idle target RPM table has no effect - this is only used to display target error.  In open loop mode you need to adjust the ISC base position table to achieve the idle speed you require.

If you want help with your fuel consumption then we will need a log of the car driving under typical conditions, a log of an idling engine doesnt tell us much.

[R24]

Hi Adam,

 

Here is the base map.

 

Best Regards,

 

Ragupathy

Ragu Tezza Base_RNR_230_0.8bar_APS set_v3 ron95smoothen_VVT_idle5.pclr

I did a log while driving but its too large to paste it here (10.5MB) after compressed. Can I email you instead?

[Adamw]

I will PM you our email address.  Otherwise, share via onedrive, google drive, dropbox etc.

If you want to reduce idle RPM at normal temp then you would reduce the highlighted values in the table below.  However if you only see 20RPM error then I dont think you will get it much better.

 

[R24]

I will try to adjust the value and monitor if there is improvement. Will update the results here after I get the info.

[Adamw]

I have had a quick look at your .pclr and logs.

As for fuel economy;  There is not too much I see wrong in your basic setup but I think the main reason for poor fuel economy is just the fuel table is not well tuned so CLL is working too hard trying to correct the bad map.  There is +/-15% CLL corrections in the log. You should turn off CLL until it is tuned properly.  

As for idle;  One thing I notice in your log is the idle stepper is continuously winding in and out - this may upset your idle.  I think it is caused by the AC step, I suspect AC request comes in over CAN bus in the vehicle?  So for now I suggest you put zeros in your AC step table.

[R24]

Hi Adam, thank you for the feedback.

Regarding the fuel table tuning, what are the main points you see that is not so right? I will input this to the tuner as I believe that was the best he can do for the moment.

Will turning off the CLL(close loop lambda-if im correct) improve a bit the fuel consumption? 

For the AC step, Im not so sure as I got this car installed with Link G4+ when i bought it over from the previous owner. Is they any way to check for that? Or will any competent tuner will be able to check on the ECU and car? 

 

Best Regards,

 

Ragupathy