just wondering guys i am having problem with my aircon idles up. once the aircon is engage it doesnt idle up. have try a few used idleup but no difference. Have check the TPS and it seems correct. Manual stated that another possible problem could be the engine coolant sensor?

anyone encounter this problem before? i have a sti v3 type r and feed back would be appreciated n thanks in advance

 

anyone? had it check at the aircon shop and told me no signal is being send by the ecu? is this true? how can this be damage since evyrthing has been running fine as the car is totally stocks ?

 

maf sensor n idle motor has been replace but still the same problem. could anyone help? have already check the tps and all seems fine though

 

sorry mate, I didnt understand your question at first but I thought that was just me.. Perhaps others don't either hence you have had no answers. What do you mean by "aircon idleup" ?

How can you try a few 'used' idleup? You make it sound like its an object ? I interpreted it as the engine idle no longer revs up by a little when your A/C compressor comes on ? But I am guessing this is not what you mean at all...

Please can you explain better what you are after ?

 

prana: idle is fine without the aircon compressor is on. once the aircon is engage idle would drop to around 500-600rpm. the idle air control valve would not compensate for the drop. my standard idle without the aircon engage is 900rpm

 

wow thats a huge drop... but it sure is much clearer now. I won't say I know the answer as I really don't but hopefully someone else who knows the idle control assembly can help with this diagnosis.

 

prana: yes am trying to figure is the drop in idle is related to the ecu ? as i have also check all the resistance base on the subaru manual and evrything is up to spec. This is driving me nuts as i have also found out other people have the same problems

 

I dont even know if there is a servo motor, but my stock ecu definitely increases idle revs by 50 with A/C on. I suspect you have an issue with the actual idle controller. Was there an error recorded on your ECU ? You can also check if the A/C Compressor signal is on, to make sure the ECU is seeing the increased load signal.

 

prana: yes we replace the idle servo with a working one and it still the same. there is no check engine light on. Aircon is working fine also. have check the harness on all the connectors and all seems within working resistance

 

any body else? this is driving me nuts!!

 

I really think its a good idea to make sure the ECU is seeing the A/C signal. Got access to a ODB2 cable ?

 

prana: this is a version 3 . its only obd1 model only the v4 upwards became obd2

 

anyone?

 

have switch alternator and still no luck. could anyone have any more suggestion?

 

AFAIK the aircon 'idle up' feature is commanded by the ECU. There is no external device that handles it. The ECU received the aircon ON signal and then increases idle speed via the Idle Air Control Valve. It's as simple as that. So either your ECU's not working, or more likely, it's not receiving the aircon ON signal.

 

Agree with that.

When my AC is engaged the idle does not drop, it simply stays the same. Would the pin-out diagram help him out?

 

is there anyway to check if my ecu is busted?

 

Have you checked all your connections on your ecu to the a/c unit? possably just a loose one causing you problems

Tony

 

tony: i have clean all the terminals with electrical contact cleaner just to be on a safe side and it still the same. check also all the connection. Am leading toward a aic valves