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trendsetter
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Last seen: 2 days 7 hours ago
Joined: 04/11/2019 - 08:51
Idle postion drops to zero immediately after start

Car is a evo9, when i start it the idle position goes from 30 to zero sometimes and i cant figure out why.

as far as i can tell all my settings are OK.

i have all corrections disabled, my idle control is set to turn off above 5.9% and it is closing the iac even if the tps stays at 3%

the tune is a bit of a mess, but theres nowhere i see that can cause it to just close the idle valve.

 

any help is appreciated

2019-04-11 0927 ECU Log.daq

 

EvoNate
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Last seen: 1 day 22 hours ago
Joined: 09/16/2016 - 18:02
Is this something that just

Is this something that just started happening?

What throttle body?

trendsetter
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Last seen: 2 days 7 hours ago
Joined: 04/11/2019 - 08:51
its an ebay big throttle body

its an ebay big throttle body.  ive had the throttle body for a while with no issues. as far as ive been able to tell all sensors and valves are working properly on the car.

the aem is new to me, i just switched from stock ecm with speed density, and ive never had an aem ems before.

as far as i can tell in the docs, the channel im watching "idle position" is the value commanded by the ecu, so the logs are saying the ems is choosing to close the valve for some reason?

EvoNate
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Last seen: 1 day 22 hours ago
Joined: 09/16/2016 - 18:02
trendsetter wrote:

trendsetter wrote:

its an ebay big throttle body.  ive had the throttle body for a while with no issues. as far as ive been able to tell all sensors and valves are working properly on the car.

the aem is new to me, i just switched from stock ecm with speed density, and ive never had an aem ems before.

as far as i can tell in the docs, the channel im watching "idle position" is the value commanded by the ecu, so the logs are saying the ems is choosing to close the valve for some reason?

I agree that it is strange for the idle position to drop to zero. With that said, it looks to me like you aren't commanding enough Idle% to actually hit your Idle Target. Based on your screenshot and coolant temp at the time, Idle Target appears to be ~1300rpm. At the 1300rpm point in your Idle%vsTarget table, the Idle Position is set to around 20%, and the log shows Idle Position at 20% or so right before it stalls. In other words, 20% isn't enough to hit your Idle Target or keep the engine running.

Try increasing the values in the Idle%vsTarget table. For example, set all the data points from 500-1400rpm to 30%. You want the channels 'Idle Base' and 'Idle Position' to be near same value once the engine is idling on it's own.

trendsetter
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Last seen: 2 days 7 hours ago
Joined: 04/11/2019 - 08:51
Bringing this back now that i

Bringing this back now that i have more time to mess with it.

the car wont start without throttle.  as soon as i get it going it idles fine even cold, but i have to throttle it for the first couple seconds.  I have the iac tables up in the mid 60s at start, but it goes to zero as soon as it sees the motor start turning.  once its been running a few seconds it seems to start controlling the iac again.

it seems to be something during cranking i cant find in the tune?

log and tune attached
 

ECU Calibration23.02v02.cal

2019-06-18 1535 ECU Log.daq

trendsetter
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Last seen: 2 days 7 hours ago
Joined: 04/11/2019 - 08:51
here is a log 3 starts in the

here is a log 3 starts in the middle.

first start is no throttle, iac closes itself

second start is a little bit of throttle, iac closes itself

third start no throttle but the iac didnt close itself and the motor started fine

i cant figure out why.

any help is appreciated.

2019-06-25 1555 ECU Log.daq