I was just curious as to whether adjusting the fuel stabilized table to compensate for some maf transfer error is ok. My maf seems to be dead on from idle to around 3 volts. From 3 volts and up, it seems to run slightly lean. Can I make up for this by increasing my a/f in the fuel table? Does this efficiently work or should I continue to adjust maf?
Are you talking about wide band values being more lean than you would wish for during WOT conditions? Grady
Yes I am. I had entered 12.5 or so for my wot at high load for a/f and when it came time to driving it was coming out to being around 13.5 or so. I then went back into the table and entered around 11.5 and then finally my wideband showed around 12.1 - 12.5 at wot. Is this ok?
I like to use the greatest load row in that fuel table for WOT use. I set it fat and the same in all cells. I then use the part of the maf curve that is never seen in use during Closed Loop to make the value used in the fuel table match the value seen with the wideband. After this is accomplished ... you can just change the value in that top row for what ever af ratio you desire Grady
The higher the value in the maf curve the richer it will be right? I did find yesterday that I went too far and once it hit around 10 the engine decided to stop making power.
Each point in the transfer is composed of a voltage and airflow value. You raise or lower the airflow value but not the voltage value. If you raise the airflow value in a cell, the pcm is gonna call for a larger pulse width. Grady
I have noticed that at wot and high load my Duty Cycle reads around 87% and the PW is around 18. I wonder if this would effect my maf at wot.
The Maf is used to determine pulse width at WOT along with the fuel table I'm excluding any factors that might + or - fuel like the high speed enrichment function you see in the Cobra. Say you have your fuel table setup for WOT at 12 to 1 Say you flow 1000kg at 4.5 maf volts for maf point 26 Say you read 11.5 on your wb at that maf voltage Your too fat at that point so You lower the airflow at that point so You then will command a lesser pulse width so You then will see a leaner display on your next WOT datalog Make sense Grady
Sorry to hijack. What if you A/F is dec3nt between gears 1-3, but at the end of 3 and the beggining of 4th you richen up to the 11's when before it was in the high 12's???
yes it does make sense. i did find today while datalogging on the freeway that when i hit around 4 volts my maf seems to stop. is this normal?
nevermind.. the maf was screwed up. i loaded up a new one and it went over 4 volts. i did adjust my maf from 3.0 volts to 4.0 volts and was able to get the a/f where i wanted it. i really had to fatten up those numbers. at first i wasnt sure if it was going to work because i was increasing them by so much.
It could be fuel enrichment function For the j4j1 it starts to come into play at 90 mph and at 120 for the t4m0 A WORD OF CAUTION HERE This thread is important! this area of fuel management is where very little margin of error takes place and one could do damage so you want to be certain this stuff is understood If I have not explained myself all that well or If anyone has any kind of Q's ... I'm happy to give more specifics if needed Grady
I understand but No need to be intimidated When doing stuff you are not sure about I did tons of it btw Have a good datalog for a baseline Make a very small change and only 1 change Do another dlog exactly the same as the baseline dlog and use the newest dlog as verification that things work like you suspect they do. Hard Data Its your friend Use it to your advantage Grady
