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Need help with fast idol air valve

Posted: Sun Jan 20, 2008 9:59 am
by Winger
I have a NH and my problem at the moment is that when I start up first thing in the morning to warm her up it will cut out twice then the idol races up and down till it is at operating temprature then it runs fine all tests thet I have done without pulling it apart point to the fast idol air valve. After phoning Mitsubishi to get a price I found out that it will cost around $400 so my question is have anyone had problems with this area and does anyone know if this part can be cleaned or serviced because at the moment I have not got the finances to buy genuine and need to fix this problem because it seems to be getting worse. Any help would be great.

Posted: Sun Jan 20, 2008 12:12 pm
by -Scott-
The idle speed controller is a stepper motor mounted just below (?) the throttle body. They have a reputation for becoming "sticky" but they're relatively easy to disassemble & clean - carby cleaner works well.

When I did mine I pulled the stepper and found it's orifice was choked with oil and dust, as was the throttle body - :bad-words: air filters! :bad-words:

I disassembled the stepper and sprayed with carby cleaner, did similar to the throttle body and stepper orifice - lots of nasty crap flowed out. :shock:

Been fine since. :)

Hint: if you pull your ISC, FIRST THING you should do is carefully wind the tip IN as far as it will go (RH screw thread) and count the steps! Just before you put the ISC back in, wind the tip all the way in, then count the same number of steps back out. If you move it too far one way or the other the ECU may not be able to regulate idle speed properly.

Good luck,

Scott

Posted: Sun Jan 20, 2008 7:20 pm
by scooby_74
The isc motors also have 2 coils in them, often they burn one out, if you can get another dead one its easy to make a good one from 2.

Posted: Thu Feb 07, 2008 8:53 am
by fasteddy
There's a new and improved Mitsu ISC that's a lot more robust. I paid about $145USD shipped to the USA. Came it the OEM packaging. Works like a champ.

Posted: Thu Feb 07, 2008 3:54 pm
by crh
My Paj won't idle when the A/C is on.

Could this be the problem? If I turn the engine off and restart it is fine, and it doesn't always do it. And never without the A/c on.

Posted: Thu Feb 07, 2008 6:37 pm
by -Scott-
Could be - what's it like when the engine is cold?