Idle/RPM Problem..

[clipse-T]

ok..when i turn the ACon , while idling, the car's rpms go down...when i am shifting..the rpms almost drop to zero making the car almost turning off. This just happens when im in a gear and shift to neutral to i can brake. Took it to the mechanic and he said there might be a problem with my ecu..### it brings my rpms down when i turn on the AC. He recommened going to mitsubishi so they can check it out. Is this my problem? Any help is appreciated.

 

[RedGSX21]

your rpms should not go down when turning on the A/C they should go up only slightly

 

[Nanan]

The ISC is susposed to raise the RPM when the A/C kicks on, if it is failing then the stalling is that. Else what rpm range does your car idle at normally, is it stable or does it kinda jump around?

 

[clipse-T]

the mechanic helped me out a bit..he raised up the idle rpms to help me out so the car wont turn off when i am driving..currently it idles at 1,500rpms and when i turn the AC on it drops to about 800-900rpms. Sometimes it goes down by itself but it comes back up..wut is the ISC?

 

[jaredgsx]

You should be idling at 750 i do believe. When you hit the ac on your car actually drops 600-700 rpm?! and they mechanic just set your idle higher? There is problem with one of your throttle componets. More than likley the biss/isc

 

[crxp-o-s4now]

Yea, sounds like your mechanic turned the biss screw...that's all. I had the same problem with my tsi so my "teacher who is a mechanic" turned the biss up..when it was really my ISC that was bad.

 

[turbotalon_]

The idle goes down because there is more load on the engine because of the AC belt. I've never heard of a car where the RPMs go up.. How can I make mine do that? Currently at idle with AC on the car shakes.

 

[crxp-o-s4now]

The idle goes down because there is more load on the engine because of the AC belt. I've never heard of a car where the RPMs go up.. How can I make mine do that?

X2..that's what i thought also??

 

[clipse-T]

X3..wut i thought also..

wut is the ISC? Please let me out, im not too familiar with this stuff. How can i fix it??

 

[Siral3x]

X3..wut i thought also..

wut is the ISC? Please let me out, im not too familiar with this stuff. How can i fix it??

A sensor on the back of the TB...look for a tan/black sensor. It's held in place by two 8 mm screws I think..and has a O ring that you must not lose or damage.
You want to chk the resistance between the terminals and come up with 28-30K Ohm resistence I belive...chk a serive manual or a Chiltons or something.
It's late , and I don't have a link handy with more details..but I'll post it tomorrow morning if you don't get more info by then.

Another prelim test before you take the ISC off and test it, put your hand by the muffler and smell your exhaust...if it's strong gas smell you're runing RICH and usualy the ISC causes that if you're idle is messed up. OR maybe you got a gauge and can tell already if u're runnig rich.
Messing with the BISS won't get you to far, but it's always good to chk the BISS too.
Don't drive it much with a bad ISC since you're plugs might get fooled easy!

 

[Siral3x]

bwt clipse-T... Tyler TX is awesome....me and a buddy went down there on a road trip ..all the way from MI last summer, just before I got married. We spent 5 days with these 2 hot TX gurls...awesome!!!! God bless America, I love this place

 

[burntheblobs]

The idle goes down because there is more load on the engine because of the AC belt. I've never heard of a car where the RPMs go up.. How can I make mine do that?

X2..that's what i thought also??

When you turn the A/C on, there is a sensor that tells the ecu this, and the ecu raises the idle slightly to accomodate for this.