Thread: STI Injector Tune using Calum r.t

So I finally got around to installing my sti injectors and everything except one thing is running good. On cold starts I have one issue. It drives fine, but in between shifts the a/f's shoot really lean and the car falls on it's face no matter what rpm. Could this be my K value is not adjust right or could there be something else that I need to adjust. I put the latency to .75. When the car is warm they still go lean, but not as bad and it doesn't effect anything. Any input would be nice!

Bump

Not sure what difference it would make, but I'm running those injectors, and did some research, they have a latency of .84 I believe. When I set the latency to that, the car ran better overall, but I wasn't having quite the same issue as you.

Hmmmm. Newb question: What would be the symptoms of the difference in latency?

Im not having as bad of issues as you but i am not running at 100% i dont think. I havent really messed with it though to see if anything changes.

When i get home i will check and see what mine is set at,(latency and k value) and post it up.

EDIT: I searched. I can understand now, why this could be an issue.

Injector Latency aka Void Blast-off Time deals with the time it takes for an injector to open and close. Large injectors take longer to open and close than small injectors and since we are talking about trying to adjust pulse widths in milliseconds, this becomes an important factor especially in regards to a smooth idle, and good gas mileage when upgrading injectors. Fortunately for stock injectors Nissan already set this factor and as long as you are on stock injectors this does not need any adjustment

well there is 2 things here. 1 there is a time delay when inj open. 2 this is dependent on battery voltage. so what you basically need to do is figure out that. with some inj company's you can get the battery offset info and set it to what your car makes for voltage running. that will help if your having issues of running lean or rich under certain conditions like fans on or ac with the lights on. it wont really change how the car reacts in between shifts. it sounds more like a throttle issue. some thing like a decel pump that tells the computer how much/when to cut fuel after you lift. it could also be a K value issue if your using the O2 feedback the computer might be adding a lot of fuel to hit its 14.7 under cruising but off throttle its not using the feedback so you run real lean. i hope this info leads you in some what of the right direction

I got the latency info here.
nissan guy needs some help - IWSTI.com: Subaru WRX STI Forums

But I understand what your saying about the battery and delay of the injector. But is there even a way to mess with this on the Calum ECU? I think I've gotten it a little better, I changed my k value to 311. I haven't gotten to check to see how it runs cold, will be doing that tomorrow.

But also, don't you want the a.f's to go more lean then rich between shifts to stay away from backfiring? I was having backfiring issues, but haven't gotten to drive the car much since I've been messing with it.

i think your best bet since i dont know much about b14 ecu's is to adjust the K value. its ok if the afr shoot lean inbetween shifts as long as the ecu can adjust them back quickenough when you get back on the throttle.

Well I adjust the latency to .85 and the idle is awesome now. But now my WOT is lean as ****.

Well seems like a I found a happy medium. WOT is now good, Idle is dead on. I turned my boost up to 16lbs and shes holding 11.4ish just fine. Still need to drive it cold to see if it's still falling on it's face.

Just out of curiousity, what are the settings you're at that gave you the results?