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Ted

Idle Air Control Valve Issue

Question

Dear Experts with my all the respect,

I am really messed with this IAC valve thing. My car has rotery solenoid valve as IAC. RSC coil for closing side and RSO for opening side. ECU provides a PWM to one and inverted to the other. (i.e. If RSO gets PWM with 75% duty cycle, RSC gets its inverted PWM which is 25%. This makes a resultant force to IAC open 50%.)

My data sheet gives the RSC and RSO values attached herewith. Please see picture 1.You can see resultant of IAC is at idling with no AC, is "closed".

But when I check it in my car, the resultant of IAC at idling with no AC is,  "opened". Please see picture 2 & 3.

Picture 2 is RSO. Picture 3 is RSC. ( eventhough it should give inverted to each other please disregard it since it's an issue with oscilloscope.i.e. time shift does not shown by oscilloscope.) 

1) I checked for vacuume leaks and none found.

2) I also checked these RSC, RSO values at different throttle adjusting screw setting. No change. 

3) Checked IAC with values in datasheet and it was OKAY.

4) Also I checked idling speed which is at around 750 rpm.

5) Also I checked rpm when AC switched on which is increased from 750 to around 900.

Pic 1  - first two graphs are RSO and RSC without AC.

Pic 2  - RSC without AC

Pic 3  - RSO without AC

 

What is the issue in my car? Why can't I get the setup in the datasheet? 

IMAG0233.jpg

IMAG0450.jpg

IMAG0445.jpg

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4 answers to this question

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How is your PCV? Are you sure it is not stuck?

 

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18 minutes ago, Rumesh88 said:

How is your PCV? Are you sure it is not stuck?

 

PCV checked no issue with it.... also its a new one..

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10 minutes ago, Ted said:

PCV checked no issue with it.... also its a new one..

If so while the engine is running on idle (750 RPM) at engine working temperature pull out the PCV while it is still attached to the hose and check if RSO/RSC PWM comes to its values shown in datasheet. Be careful when you pull out the PCV because the rubber grommet may have become hard unless it has been replaced recently.

 

Edited by Rumesh88
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17 minutes ago, Rumesh88 said:

If so while the engine is running on idle (750 RPM) at engine working temperature pull out the PCV while it is still attached to the hose and check if RSO/RSC PWM comes to its values shown in datasheet. Be careful when you pull out the PCV because the rubber grommet may have become hard unless it has been replaced recently.

 

Will check nd let u know..

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