cold start: how to fix rpm over/undershoot
Thread Starter
Joined: Mar 2003
Posts: 8,319
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From: North Carolina
cold start: how to fix rpm over/undershoot i start my car and the rpms go up to ~1350 then way way low to about 400 and then over shoots again to 1100 and then goes to 900 and then back out even at 1000.
i also see that the dynamic airflow fluctuates a lot too with the iac count staying the same. i dont know what i can do here or what i can adjust really. any ideas?
also i cant find out the max iac position, what is the max number of iac counts?
i also see that the dynamic airflow fluctuates a lot too with the iac count staying the same. i dont know what i can do here or what i can adjust really. any ideas?
also i cant find out the max iac position, what is the max number of iac counts?
Thread Starter
Joined: Mar 2003
Posts: 8,319
Likes: 1
From: North Carolina
also, can i adjust idle spark,i see it goes down to 1.5* at peak rpm and at about 22* at lowest dip in rpm and once it evens out its only at about 12*, is this normal or no?
Originally Posted by WS6FirebirdTA00
i start my car and the rpms go up to ~1350 then way way low to about 400 and then over shoots again to 1100 and then goes to 900 and then back out even at 1000.
i also see that the dynamic airflow fluctuates a lot too with the iac count staying the same. i dont know what i can do here or what i can adjust really. any ideas?
i also see that the dynamic airflow fluctuates a lot too with the iac count staying the same. i dont know what i can do here or what i can adjust really. any ideas?
Sounds like a vacuum leak to me, if IAC is not reacting.
Thread Starter
Joined: Mar 2003
Posts: 8,319
Likes: 1
From: North Carolina
Originally Posted by wrencher
Sure sounds like a mechanical issue & not a tuning issue?
Sounds like a vacuum leak to me, if IAC is not reacting.
Sounds like a vacuum leak to me, if IAC is not reacting.
there is nothign wrong, this happens for about 10 sec when you start the car cold then its fine. the iac motor is at 310 right now and i dont know if i can set it higher. the tb is ported and epoxy fillled with copper tube so its letting less air in, but i have read of oters with this problem and stock tb. once the car warms up just a little bit its alright.
Thread Starter
Joined: Mar 2003
Posts: 8,319
Likes: 1
From: North Carolina
Originally Posted by 2xLS1
Your adaptive idle spark control - overspeed/underspeed is probably causing the timing instability and may even be agrivating the condition.
I have the exact same problem so keep us posted. I have tried messing with the RAF table although I havent had any luck. This problem came about when I plugged the MAF back in after SD tuning(not sure why this happened since it is in open loop at cold start).
This was not a problem on cold start ups when I was still in SD mode. Why would this start after pluggin in the MAF?
This was not a problem on cold start ups when I was still in SD mode. Why would this start after pluggin in the MAF?
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Verdad Gallardo Thread Starter
Joined: Mar 2003
Posts: 8,319
Likes: 1
From: North Carolina
hot idle the iac counts are about 30, once the temp is about 160*+ at about 130* the iac counts are right at about 65-55. ive opened the TB blade more but if i go any more then im gonna be left with 0 iac counts on hot idle
Originally Posted by sevanseriesta
My Iac accounts do not go to 0 ever is there something wrong with my car.....Do you also think that may be the reason why it is not idleing right.
Originally Posted by 2xLS1
Your adaptive idle spark control - overspeed/underspeed is probably causing the timing instability and may even be agrivating the condition.
