MegaSquirt AFR

[seight]

Not the usual question, but perhaps a dumb one!

When i had my car RR'd my lambda wasn't working properly so what I was wondering was whether simply logging in MS will allow me to generate what my current AFR table is?

Then I can load it back into MS to use as an initial target AFR table should I want to play with the live tuning.

thanks
Mike

[Quagmire]

*edit - Just read your post again - is the car running fuel on MS already? If it is then you can simply connect your chosen electronic device and open the target AFR table to see what is in there.

If not using MS for fuel or it is but has no target table then read on...

I have made some steps for logging the fuelling to work out a table for my car - I am working on getting the last few bits together before I install injection. I currently get around 24-25mpg from my old SU's and the car drives well so I think that using the current fuelling as a kind of "baseline" would be a sensible way to go.

I figured that if I logged my AFR's I could use a bit of Excel-fu to generate a table of the AFR's I am getting. I did actually get around to trying this out, and it kind of worked... but I cant seem to find the file - I stopped the exercise as I noticed I have (and still have) an offset between the true wideband reading and the MS reading, as I need to move the ground for the LC1 sensor.

I'll continue to have a dig around to see if I can find the file and figure out what steps I took to get a table together from the logs...

[DaveEFI]

IIRC, the actual fuelling on an MS is controlled by the VE table. The AFR table is a target AFR which TS etc will use during VE analyse, but you don't want to do that if the car is running well.

So if you have a good working VE table, you need to translate that into an actual AFR table. And I'm not sure how you'd do this.

[Quagmire]

IIRC, the actual fuelling on an MS is controlled by the VE table. The AFR table is a target AFR which TS etc will use during VE analyse, but you don't want to do that if the car is running well.

So if you have a good working VE table, you need to translate that into an actual AFR table. And I'm not sure how you'd do this.

Sorry I am rubbish, that is what I was trying to say - If you have a car that has been tuned to the AFR target table then great - if you don't, like me (as I am running carbs, or if you have a car running well that was tuned by hand) then what I have been trying to do is pull my observed AFR's from datalogs and rebuild what is being recorded into an AFR table.

Then in theory I can just set my AFR target table to match the one built from observation when I switch to injection and tune to that to get something pretty close to the fuelling that the carbs are delivering (simplistic view forgetting all the various enrichments).

[DaveEFI]

I've asked on the MS forum if there's a way of translating a VE table into an AFR one. I'll post any relevant replies here.

[seight]

You're both right, I think

Target AFR table was not used as it's just some default stuff that was there to start with. Like quagmire I want to know what my actual AFRs are now that it's running well. I was thinking I could do the same kind of logging exercise somehow.

Anything you could find out would be great.

Mike

[Cobratone]

The way I'd do it is: -
Do a datalog and use megalog viewer to see the afr trace. Open your ve table in your current msq in the same megalog viewer (mlv) frame. Draw a blank table on a piece of paper to correspond with your ve table x and y axis. Step through the log one step at a time and look at the ve table, as you go through each cell look on the graph for the actual afr and write it down on your blank grid, it may take you some time to step through each cell that has been used but you will eventually get all the afr figures into the blank table on the cells that have been used. Lastly read through this again as , although I know exactly what I mean, I may not have written it down in an easy to understand manner