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View Full Version : Desired Airflow Oddness


Dale
February 5th, 2008, 02:03 AM
Ive been trying to get this car to stay running at various points in the temp range. The biggest one that boggles me is full warm temps.

I can start the car from being off overnight. Start it up, drive. It run at full 180 for good 10-15 min. Says it needs .6lbs more of air.

But turn the car off, let it sit maybe 5 min. Start it back up and now its saying its subtracting -.98lbs of air.

WTF? Now if it was smaller incraments, so be it. But that is a hugh difference. How do I tune for something like this?


Now also, for anyone not familer with my setup. This is on a TPI motor, with a TPI IAC.
Dale
February 7th, 2008, 04:29 PM
Here is a log file. Please help me figure it out.

Somewhere around "21:15" is where the car is full warm. I turn it off for a few seconds, then start it back up.
hquick
February 7th, 2008, 06:01 PM
Without looking at the log....(don't have time right now) I think you'll find the motor keeps getting hotter after it's been sitting for a little bit (no cool air to cool the radiator) and therefor it may have something to do with your ECT VE settings.
Dale
February 8th, 2008, 02:09 AM
Cant find that chart quick, do you know the number of it off the top of your head?
Chunx
February 14th, 2008, 09:20 PM
"Increased the Startup Friction Airflow Correction table for better starts. Although this doesn't really have to do with idle swing, I thought I'd include it because it seems to be a common problem. I increased this table by 4 grams/second across the board. Now, my warm start issues are gone. It was stumbling right after startup, barely running because there wasn't enough initial airflow. Adding air in here is a good, temporary way to add in the airflow, which will be decayed out after the first 30 seconds or so."

What about this from the idle tutorial for warm starts?

edit: just read the first post again....are you having warm start stumbling? or just the incorrect desired air readings?
ack, yeah, im a rookie :)
Dale
February 15th, 2008, 07:54 AM
I'm having just incorrect/drastic differences in desired air readings after the motor is warm and restarted.

Rookie or not, any input is helpful.
Dale
March 8th, 2008, 12:58 PM
ok. Bringing this back to the top.

I have loaded an LS1 version of chart B4403. It has helped, but is still off.

When I bring the car from a cold start, warms up. Its steps move to about 180'ish. turn the car off, start back up, the steps jump to about 110-115. What would cause the steps to change even though the motor temp is the same?