Idle speed

[Nelmo]

Hi, I've just bought an old, 2001 Yaris 1.0L for my son, as his first car. Great little car but there is one issue; the idle is very low (550-600 rpm). It doesn't stall but the steering vibrates slightly, which is a bit disconcerting. 

Now, the guy I bought it off did mention he changed the Battery recently and, reading up, that can reset the ECU and the learned idle. However, he changed the Battery at least 2 weeks ago (possibly longer) and I drove 30 minutes to get home, another 15 minute drive today and I sat in the driveway trying to do the manual process (ignition on, off, on, wait) but nothing has changed.

Is it just that they all idle that low and vibrate like that? Seems weird if so but I'm sure we'll get used to it. 

 

[stantheman1]

It sounds a bit low to me as well, 750 to 800 rpm sounds more like it. It may just need a good service, the MAF sensor may also need a clean, vacuum leaks can have that effect also. Do you have access to a code reader if so check to see if there are any codes pending and how long ago the MIL was turned off (if indeed it has)of course I am assuming the engine warning light is not illuminated when running.

[Stevie J]

Its about right - previously to my current car, I owned a 1999 1.0 Yaris which also used to idle very slowly when the engine was up to operating temperature, it would sit at about 600rpm, and often I used to think it was going to stall, but it never did, in the 5 years I owned it. There was also vibration through the steering column and other parts of the cabin when the car would idle down to 600rpm, and I would see the rev counter drop to halfway between 0 and 1000 rpm.

You could try checking the air fliter is clean, but unless the car has done high mileage (over 80 - 100K miles) I wouldnt be inclined to mess about with the MAF, as they are easily damaged by people that dont know what they are doing, and they are difficult to clean correctly. Usually a faulty MAF would cause very rough idling and frequent stalling, and would be likely to set a fault code in the ECU and light up the Engine management light (the orange light on the dash in the shape of an engine). So unless the car has such an irregular idle that makes it often stall, then I would be inclined to live with the issue.

[Madasafish]

Clean MAF sensor. With carb cleaner (sensitive - great care needed)

Clean throttle body with carb cleaner. Be careful do not use too much...

Check air filter.

 

Leave 24 hours after cleaning throttle body or you will get misfires when you start up as cleaner is volatile...

 

[Nelmo]

Thanks all - I think I'll go with StevieJ and live with it - there is no engine light and it is not stalling - 'if it 'aint broke, don't fix it'

 

[Yaristotle]

In anycase it is well worthwhile replacing the air-filter, though. There is a whole choice here:

https://www.autodoc.co.uk/car-parts/air-filter-10360/toyota/yaris/yaris-scp1-nlp1-ncp1/17569-1-0-16v

[lani100]

That's normal, they all idle very low

[scannerman]

On 7/9/2020 at 6:46 AM, Madasafish said:

Clean MAF sensor. With carb cleaner (sensitive - great care needed)

Clean throttle body with carb cleaner. Be careful do not use too much...

Check air filter.

 

Leave 24 hours after cleaning throttle body or you will get misfires when you start up as cleaner is volatile...

 

I have read a number of times that Carb cleaner leaves residue after drying so is not recommended for cleaning the MAF sensor as it can corupt the readings. You can buy a MAF cleaning spray that leaves no residue.

High milage cars can build carbon deposits in the throttle body that impede the operation of throttle butterfly flap.