Fuel Trim QuickTune

[tzikis]

Hello everyone, I was just looking for something on PCLink and couldn't find a straightforward way to do what I wanted so I thought I'd ask here.

I have a 2-cyl engine, with individual injectors and individual wideband Lambda sensors on each cyl. For *reasons*, each cylinder has slightly, but substantially different VE so I really need to tune them to different values for each cell.

From what I've seen so far, the "right" way to do this is to set up sequential injection, and use individual cylinder fuel correction. I've Quick Tuned my engine using Lambda 1 & Fuel Table 1 to meet the AFR/Lambda Target Table.

What's weird is that I expected to be able to use Quick Tune and select my Individual Cylinder Fuel Correction Table and Lambda 2 to meet the AFR/Lambda Target Table as well, but I see that I can't do that. I also don't seem to be able to use a different Fuel Table for each cylinder, in order to take advantage of Quick Tune. From what I understand I can't even use Quick Trim with Individual Cylinder Fuel Correction Tables.

I was expecting to somehow be able to Quick Tune each cylinder based on each lambda sensor, considering that in Closed Loop Lambda (which was going to be my next step, but after I had set up the engine properly), I can in fact link the injectors into banks and banks into lambda sensors, so I can have each injector track their own lambda sensor.

So my question is, is there any way I can quick tune each cylinder based on their own lambda sensor? Any work arounds or suggestions in general?

Thanks

[Adamw]

No I cant think of any way to do that, it is a pretty unusual situation.  The closest I could think of is you could enable dual channel closed loop lambda with each cyl as a "bank".  Turn on long term trim and over time it will build up a correction table for each cylinder that you could then copy to the individual cyl trim tables.  It is not instantaneous correction however, it takes time for the long term correction to achieve equilibrium.  

Probably best to just do a few logs of ramp runs and build the corrections from those.  

[tzikis]

Thank you @Adamw. I was planning on doing this, but wanted to have a base tune that more or less hits the right AFR across all/most cells, and then enabling Close Loop controll.

For what it's worth, I think being able to specify anIndividual Cylinder Fuel Correction Table as a target for the Quick Tune function is a valid feature request that makes sense (and you can already specify a specific Lambda channel as the source). I see no need to do this in a time-consuming and manual way.

Is there any chance this could be implemented in PC Link in the future? Is there generally a place where we can suggest features?

Thanks, and kudos for the great job \m/

[Adamw]

I can put it on the wish list but its priority will come down to how many have requested it.  This is the first time I have ever seen it asked.  It would be very unusual to have to tune a large 3D table for each cylinder, typically all cylinders are exposed to similar manifold designs, valve timing, compression ratios etc so VE is similar on all cylinders.  Any differences due to air flow bias, cooling system bias or fuel system bias would generally be a taken care of with a fairly basic individual cylinder trim (single cell) or a trim covering a fairly broad range of operating conditions (ie 2D or a very basic 3D).