PDA

View Full Version : initial startup rpm question?



whackem04
December 19th, 2009, 03:15 AM
i recently upgraded O/S and when my truck starts up it revs to 12 or 1300 rpms and decays naturally? Question is, what table adjusts how high it goes? I'd like to get it down to only 1000. thanks

WeathermanShawn
December 19th, 2009, 04:01 AM
Not exactly sure what Tables on your OS..but normally you are talking about the "Startup Friction Airflow Correction" (grams/second). You can normally control the amount and decay rate to your own specifications.

Occasionally it can be too much air in your "Desired Airflow". If it is only occurring when the vehicle is not moving..that gives a clue. Also if drops immediately or if it varies as your ECT increases, that can be helpful.

If you are not moving, I would bet it is your OS's equivalent of the "Startup Friction Airflow Correction. You can increase the decay by increments of +50%, and see if that is the culprit.

whackem04
December 19th, 2009, 06:32 AM
my o/s is 12212156. i tried messing with those but it still does it. anything else to try?
what about b4604?

WeathermanShawn
December 19th, 2009, 07:40 AM
B4604 on mine reads all zero's (0) for that table.

What about your Throttle Follower Airflow Tables? Should all be zero's (0) at zero (0) Throttle opening. Obviously you can lower your Desired Idle Speeds, but this sounds like you are getting additional throttle opening via the IAC.

There are a lot of airflow tables, but just to confirm..this is only at Start-Up and car is not moving, correct?

whackem04
December 22nd, 2009, 04:22 AM
this is only on start-up when cold. it throttles down smoothly but it sounds like a nascar truck on start-up. Doesnt bother me but the neighborhood doesnt like it. whaaa

WeathermanShawn
December 22nd, 2009, 12:28 PM
I make sure B4603 stays below 900 Rpm's through all my ECT's (I idle at ~775 Rpm's). I have constructed my B4307 Table to give me more air than stock with high ECT's, but have generally lowered it as it approaches cold temperatures. Of course, I did RAFIG, and I am within .5-.75 g/s on my airflow curve.

There are also a couple of sneaky airflow corrections for Catalytic Lightoff Idle Offset. I set all my multipliers to zero. I have not messed with Startup Airflow Correction, but I have done some work on the Startup Friction Airflow Correction.

On my Learning Airflow Corrections, I used SSpdDmon's Idle Tutorial.

I have had the same problem you are having. I also have good neighbors, and figured out how to soften the initial idle RPM and sound, so it would not wake up the entire neighborhood.

Superado
January 6th, 2010, 04:39 PM
any update?

I have the exact same issue...

mr.prick
January 6th, 2010, 05:38 PM
My car used to do this when RAFIG was not right.
The "tuner" left it high in the low ECT areas.
One of the reasons I bought EFILive. :)

Superado
January 6th, 2010, 06:29 PM
Ever notice how completely different the car vs truck stock tune values are in Idle Flare Control?