Idling at 500rpm

[Hlkh]

Hi Bro,

 

There is some problem with my idling rpm.

 

something stop at traffic light the rpm will drop to 500 rpm and stay there den sometime slowly go up to 850rpm like that.

 

sometime just normal at 850-900rpm.

 

Any bro encounter this before? is there a problem?

 

Thank You,

[So_nice]

it shouldnt happened to EFI vehicle.(assuming urs is an EFI) u should send it into the workshop for a check

[Hlkh]

can any workshop outside check?

i have nv service in agent before

[So_nice]

is ur car still under warranty? if yes just go back to them. outside workshop can do it, but must find the right one if not kanna carrot head!

[Friendstar]

what is ur ride?

[Smhomie]

I wouldn't worry too much about this It behaves as such because your ecu controls the Idle Air Control valve (IAC) which is located at the throttle body before your intake manifold. This serves to regulate the flow of air into your combustion chamber when the throttle plate (butterfly valve) is naturally closed at a stationary position.

 

You may dismantle the throttle body and clean the carbon deposits clogging it with carb spray. It will help to bring up the revs although not necessarily a good thing. The ecu regulates inflow whilst keeping idle revs for you based on coolant temps, intake temps, engine load and gear position

[Yc86]

Hi Bro,

 

There is some problem with my idling rpm.

 

something stop at traffic light the rpm will drop to 500 rpm and stay there den sometime slowly go up to 850rpm like that.

 

sometime just normal at 850-900rpm.

 

Any bro encounter this before? is there a problem?

 

Thank You,

 

What car are you driving? My parent's corolla G9 (A) also gets this same problem..

 

Only when stop at traffic lights. At first thought it was the air-con idling, but even without the air-con it still drops.

Also regardless whether it's in D or N.

 

Might be the idling valve or a sensor that's dirty?

For now, just have to live with it. Hopefully the engine doesn't stall or something. =/

 

Can't figure out what's the cause.

Edited July 15, 2008 by Yc86

[Apollo]

500rpm is rather normal leh.. esp if u hv a car listed as ULEV.. ultra low emission vehicle.. eg Colt.

[Kb27]

I agree with smhomie. It might be the IAC or just the throttle body is loaded with oily gunk and needs a cleaning.

Your rpm should stay steady all the time at 700~800rpm according to the manual.

 

Just curious, do you use aftermarket air filter such as K&N ?

[Rickster]

My 5 month old mazda 2 also idles at between 400-500rpm. Sent it to AD for a check and they say its normal.

[Happily1986]

i used to drive hiporolla (A) also. The rpm drop is normal due to sudden increase in electrical load on the alternator when the aircon compressor comes online. The dip is slight (at most half a division) and momentarily. In fact if you listen carefully you can hear the secondary circuit coming online cos the magnetic relay gives an audible "click". Nothing out of the ordinary. Unless your rpm dip is very drastic.

[Hlkh]

no more warranty liao...

any gd workshop to recommend?

[Hlkh]

my ride is lancer 04 model

[Hlkh]

thanks bro,

if DIY to clean the throttle body and IAC value any problem?

[Hlkh]

i think i will try smhomie method 1st

[Smhomie]

No, I shouldn't think so. Other than sensor connectors (if any), the throttle body is purely mechanical. Just spray like hell and use a cloth to rub away the carbon deposits from internal surface and both sides of the plate surface the IAC most likely may have a small gap opening thingy, just use carb spray and wipe with cotton buds since your finger may not fit inside thats all to it.

 

Of course you must first dismantle the throttle body + intake hose + vacuum hoses and clips before doing the above

[Hlkh]

any place to recommend for clean IAC

i m using K&N air filter

[Hlkh]

bro where to get card spray ?? how much it cost?