Idle Question

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dirtyharry

New Member
hi guys.
just joined the forum, as my wife has a 05 lancer ch 2.4 (4g69).
Anyway ive noticed that in the technical manual it says the car is supposed to idle 750rpm + or - 100rpm.
So ive noticed that she has been experiencing this with her car and im not sure if this is normal,
basically what it does, is say you start the car and drive it and it warms up, most of the time the idle will sit around 850rpm (which is within the limit i guess). But then if you say turn the car off and start it again the idle from then on will stay around 750rpm.
Now id prefer it to idle around 750, however im just curious what other people's lancer is doing, or if this is normal.

For your info, i dont think there is any air leaks, the valve clearance is within spec, the throttle body has been cleaned, and the ecu doesnt show any error or pending codes (i have evo scan software).

Any ideas if thats normal? (i know the rpm is still within the specs, but id prefer if it would idle at 750rpm so that it uses less fuel)
 
Mine does this aswell. 100rpm at idle, it isnt worth the hassle to save an extra 10cents for every 3 tanks you fill.
 
My car idles around 1500rpm on cold start up. Once it's warmed it will idle at 750rpm. This is normal, it idles higher on a cold start up to warm the car up faster but not too fast. I wouldn't be worried.
 
yeah it idles high at cold temperature and then drops down to 850 when its hot, however like i mentioned earlier if i turn it off and switch it back on again straight away it sort of "decides" hey lets idle at 750rpm now.

ive also noticed that it would do that after i switch the air con on and off (after the engine if warmed up offcourse), so it would drop from 850 to 750. its like it has a mind of its own.
 
on another note, have any off you replaced the front oxygen sensor on these cars? if so did you use a genuine part of a aftermarket, however the proper one with the proper connector? and what brand was it? denso? and if so how much was it and what was the part number?
 
dirtyharry said:
on another note, have any off you replaced the front oxygen sensor on these cars? if so did you use a genuine part of a aftermarket, however the proper one with the proper connector? and what brand was it? denso? and if so how much was it and what was the part number?
Click to expand...

I don't know if this is relevant anymore but I got quoted $390 per oxygen sensor from Mitsubishi. Cheers
 
Don't worry too much about the idle unless it is over revving in idle position after the car has warmed up fully (when temperature gauge reaches halfway).

After a full warm-up, the idle should sit around 750RPM (+ or - 100) depending on if the A/C is turned on or not. In fact at around 750RPM, the car should feel like it's not even turned on (very quiet from inside).

Just remember, as the previous poster said, the A/C does play a big role in the idle of the car.

Furthermore you should keep a habit of warming up any car first thing in the morning, new or old, for at least 1-2minutes before taking off. On my 07 Lancer CH I usually warm up until the temperature is in between 'Cold' and half way which takes around five minutes.
 
mine idles a little more I think it is around the 850 - 950rpm but is no big deal - i would only be worried if the idle crept up over the 1200rpm and stayed there as this could mean that the thermo stat may be open all the time and not allowing the warm coolant to warm up engine so the car is registering cold start running mode
 
chowetime said:
mine idles a little more I think it is around the 850 - 950rpm but is no big deal - i would only be worried if the idle crept up over the 1200rpm and stayed there as this could mean that the thermo stat may be open all the time and not allowing the warm coolant to warm up engine so the car is registering cold start running mode
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My average is around 800RPM.
 
Idle speed is also determined by coolant temp. Thats why in winter it sits up around 1300, until the car warms.
 
Also if you have any accesories on such as A/C, lights, sometimes even radio, the idle will creep higher than normal
 
you can pick up a universal o2 sensor off ebay from an Aussie seller for $49....I have switched both of my old ones with these and they work perfectly.....its just an easy cut and then crimp with the supplied connectors....
 
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