jacobcartmill

iTrader: (6)

i just installed my PFC + datalogit and got everything set up and everything seems great. the only problem is the throttle pumps seem to be a little lean. for instance, when i touch the throttle to take off from idle it stumbles for a split second before it revs, but if i stab the throttle to the floor it wont hesitate before it revs...
if i am sitting there revving in neutral with light throttle it will stumble for a second before it revs up.


i also have some SLIGHT throttle issues, but i need to go out and adjust my air bypass screw as the PFC FAQ says to do during install... would this possibly fix my problem? i'm thinking that maybe the PFC has the throttle pumps calculated to where the air bypass screw needs to be out 1/2 turn, and if its not out 1/2 turn the throttle pumps will be incorrect?

cewrx7r1

iTrader: (2)

Read the PFC manual Page 29. Then go to the DL Settings 2 where you will see it.

But more important is the INJ vs Accel TPS which controls/uses the Accel Inj (ms).
256 on either side is the same as 100%. Left side is %tps movement, right side is what amount of Accel Inj (ms) that is applied.

Bottom INJ vs Accel TPS is 20 25. That mean if you TPS move 20/255 * 5 volts the
25/255% of the Accel Inj (ms) will be used.

Just by changing the 25 to 50, you get twice the fuel as before. 25/255 compared to 50/255.

Also check yout TPS voltages.

Want to learn more about, buy my notes.

jacobcartmill

iTrader: (6)

thanks for the response

ok i messed with the INJ vs Accel TPS and it didnt change anything, no matter what values i used. i tried changing the bottom, middle and top values, doubling them, tripling them, etc. no change.

i got it mostly smoothed out by richening up the base fuel map under 2000 rpms.

cewrx7r1

iTrader: (2)

That shows that the problem was not the acceleration map but the base map way too lean. Proper AFR logging would have shown that.

jacobcartmill

iTrader: (6)

um. yeah.

thanks

cewrx7r1

iTrader: (2)

Meaning like:
(1) a properly tuned hot idle is required before tuning a cold idle.
(2) properly tuned cruise, and cruise to low boost transistion is required before fine tuning the acceleration parameters.

There are tuning blocks that should be accomplished in order. Otherwise you waste time going back over them. Your problem is an example.

I have owners contact me after their fine running engines were power tuned , and then only run good on boost.

twokrx7

iTrader: (1)

Buy the notes, they are worth every penny if you are doing your own tuning!

jacobcartmill

iTrader: (6)

thanks