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Idle problem when A/C off


Jose Augusto
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Hi,

I am having a problem with Evo 9 plug-in ECU. When I am in idle and turn on AC, steps going down perfectly.. With AC steps set to 20 and I am with 120 steps, instantly go to 100..

But when I turn off, steps return one by one very slow! If I am with 100 steps and turn off AC, don’t go to 120 instantly!

But if I am in open loop, everything right!

Does anybody help me?

I tuning a V88 a month ago and didn’t have same problem.

(Evo 9 Plug-in with last firmware and last PC Link)

 

Thanks in advance!

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Not all of the AC step is removed when AC is turned off, this is because generally your AC step is larger than it needs to be to quickly increase torque, this results in the RPM increasing above target, then over a few seconds the closed loop will remove some steps to bring idle back to target.  I think it is around 65% - so for example if AC step is 20, then when AC is switched on the idle position will have 20 steps removed, when you turn AC off the idle position will have 13 steps added back on.  

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On 7/1/2022 at 9:54 PM, Adamw said:

Not all of the AC step is removed when AC is turned off, this is because generally your AC step is larger than it needs to be to quickly increase torque, this results in the RPM increasing above target, then over a few seconds the closed loop will remove some steps to bring idle back to target.  I think it is around 65% - so for example if AC step is 20, then when AC is switched on the idle position will have 20 steps removed, when you turn AC off the idle position will have 13 steps added back on.  

Adam,

But when I turn off A/C, no steps added back.. And closed loop will add one by one step until stabilize..

AC steps was correct, because when in open loop, with ignition idle too, I can turn on / turn off AC and idle keep perfectly.

I will make a log turning on / off AC and attached here.

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  • 2 weeks later...
On 7/1/2022 at 9:54 PM, Adamw said:

Not all of the AC step is removed when AC is turned off, this is because generally your AC step is larger than it needs to be to quickly increase torque, this results in the RPM increasing above target, then over a few seconds the closed loop will remove some steps to bring idle back to target.  I think it is around 65% - so for example if AC step is 20, then when AC is switched on the idle position will have 20 steps removed, when you turn AC off the idle position will have 13 steps added back on.  

Adam,

Could you take a look at logs?

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On 7/1/2022 at 9:54 PM, Adamw said:

Not all of the AC step is removed when AC is turned off, this is because generally your AC step is larger than it needs to be to quickly increase torque, this results in the RPM increasing above target, then over a few seconds the closed loop will remove some steps to bring idle back to target.  I think it is around 65% - so for example if AC step is 20, then when AC is switched on the idle position will have 20 steps removed, when you turn AC off the idle position will have 13 steps added back on.  

Adam,

Did you have some time to take a look?

 

Thanks in advance!

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