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In the book, for the first case study(page 141), it has you set the cells for 75* and above to 1.12(12.54 afr) in the OL EQ Ratio Gas (Gear).
Why wouldn't you want these set to 1.00(14.68). This is for tuning the MAF. You are disabling all the fuel adders.
Thanks
Sarge
You must have a newer version than mine but I am pretty sure he recommends you set those values to 1.17 which = about 12.54:1 AFR. You are making all of your commanded fueling the same for all adders so you are commanding 12.54:1 for your entire datalog. This way you are not chasing different AFR while datalogging your AFR error%.
Sorry yes it is 1.17. I do have the new book.Quote:
Originally Posted by superwagon
14.68 could hurt your motor if you get on it too much since this would be too lean under WOT or rapid acceleration. also would be too lean for cold starts if the weather should be cold where you are tuning and car will not even idle if you have big cam.
As long is PE is richer doesn't matter if you put it at 1.00, the ECU is going to take the richer of the two.
Exactly what I was thinking.Quote:
Originally Posted by Ben Charles
I guess its not bad practice to put the 75+kpa cells to desired AFR, but its not neccessary as long as PE is there.
Actually I find that to be 180* out. You want to set the OL table to the stock values up to about 120 degrees to provide cold start enrichment and then 1.0 for the balance of the table(s). Set the PE to a straight 1.15 (N/A) or 1.23 (FI).
Tuning always takes place when the engine has reached its operating temp.
That way you so you can tune MAF/VE to lambda 1 (Stoich) in non-pe mode and .85/.77 (depending on setup) in PE based on the commanded values. You then go back and log a cold start, just to make sure you don't have too much/too little low temp enrichment and tweak as required.
At least that is how I learned/studied to do it. :cheers:
Ed M
I thought we were talking about tuning MAF and VEs which would mean that PE would be set to same value as what is in the OL FA table so that we would have the PCM always trying to achieve the same value under all driving conditions to create an AFR correction factor to use. Regardless, if you follow steps in Don's book you cannot go wrong.
PE is not set to the same value as OL FA. The PE is set to "add" fuel when you enter WOT above the stoich value (1.0) normally set in the OL FA table(s) for non-pe fueling.Quote:
Originally Posted by JamesLinder
Ed M
Yes sirQuote:
PE is not set to the same value as OL FA. The PE is set to "add" fuel when you enter WOT above the stoich value (1.0) normally set in the OL FA table(s) for non-pe fueling.