BIRDONNOS

iTrader: (3)

well i put 42lb injectors in my car tonight and scaled the ifr table accordingly, and after the install all of my ltft went to 25 every cell, does this mean i am running lean or rich, and should i scale the ifr table up or down. this is the only change i made and now the ltft's are all at 25

AnthonyR

iTrader: (3)

+25 is lean, -25 is rich. You need to scale your IFR table way up for those injectors... I know there is a table around here somewhere, I'll see if I can dig it up.

*EDIT*This will help you get in the ball park...you'll need to tweak it to get exactly where you need to be...just put 42 in the third column http://www.speeddemonmotorsports.com...ectorscale.xls

BIRDONNOS

iTrader: (3)

ok after doing some logging today i finally got the lifts from -4 to plus 4 all over the graph. going from a 3 bar 37.1lb injector rated at 43.5 psi and scaling it to the ls1 58 psi was harder than the formula in the unit conversion according to the ltfts. the 36lb injector rated at 43.5 came out to a 42.84lb on the ls1 58psi setup. so i divided 42.84 by 28.71 which equals 1.49. i scaled the IFR by 1.49 and this is when i got the 25plus ltfts all over the place. so i did alot of logging and got the lifts down to plus 4 to -4 but the table isnt scaled at 1.49 its scaled at 1.15 and my ltfts came closer to normal. does anyone see a problem with having to scale the table 1.15 instead of 1.49 as long as my fuel trims are in line. i need to know if this was the correct way to do this. thanks guys

BIRDONNOS

iTrader: (3)

anyone?

narcszm

Let's pretend partial credit counts. Put all your math up here.

BIRDONNOS

iTrader: (3)

what do you mean by this

BobDoLe

iTrader: (11)

bump - after much searching, this seems to be the proper way to deal with LTFT issues after swapping to bigger injectors.

in my case, when i let off the throttle, LTFT's go to -13 to -15. my idle is also a little rich.
o2 readings seem to be just like my stock injectors everywhere else but below 30kpa. i'm thinking my fuel pressure (gauge on order) is a little higher at idle and this may be why scaling IFR for 58psi (on stock fuel pump) results with rich deceleration/idle.
in my case, since my LTFTs are reading negative, i'm thinking of scaling the injectors a little bigger at idle or deceleration kpa range.

it seems like a lot of people change the ve table, but my fuel trims were fantastic before swapping injectors.
any thoughts on this? is re-scaling ifr the right way to correct for this?

Engine_HP

iTrader: (1)

did u adjust ur PCM for the new injectors so the PCM will understand how mich fuel to give ?

BobDoLe

iTrader: (11)

so far, just the ifr table and min/default pulse widths cut 50%.