Yaris Engine Noise/Idle speed

[x_enginerd]

Hello folks, need some troubleshooting help

I have a whirring noise coming from my engine; typically around 2500-3000RPM. The noise typically develops after about 20mins of driving. I also have an issue where the idle speed of the engine will drop and the car starts to shudder as if stalling. Say a typical idle speed of 600RPM which will drop momentarily to under 500 then return to 'normal' speed. Both issues seem to have started at the same time.

It is possible that my fuel consumption has increased slightly, although I am still running winter tires thanks to Calgary's unpredictable 'spring' weather.

The local 16yr old mechanic at my local toyota shop can't help unless an engine fault code is displayed.

Anybody have any ideas on possible causes of the noise/low idle speed.

Cheers

[x_enginerd]

Oh some other info:

1.5L with 50000kms(30k mi) and all highway driven.

[ReTread]

You don't mention the level of maintenance on your car....The dealer will not do this for you unless asked.
Can't help with the noise problem without a better description, but the idling / stalling problem might be solved by 1) Mass Air Flow/ Temperature sensor cleaning, new air filter 2) Throttle body remove and clean with attention to cleaning the Idle Air Controller Motor which is built into it....3) new plugs 4) pressure clean fuel injectors

[RningOnFumes]

Along with what ReTread has said, check under the hood for broken/cracked rubber and plastic where your intake components are...because you say you hear a noise. If it's constant, have someone sit in the drivers seat and rev the engine for you.

[x_enginerd]

Originally Posted by ReTread

You don't mention the level of maintenance on your car....The dealer will not do this for you unless asked.
Can't help with the noise problem without a better description, but the idling / stalling problem might be solved by 1) Mass Air Flow/ Temperature sensor cleaning, new air filter 2) Throttle body remove and clean with attention to cleaning the Idle Air Controller Motor which is built into it....3) new plugs 4) pressure clean fuel injectors

Hi,

ReTread, Yeah I don't believe in maintaining my cars, no seriously the maintenance has be done as per the maint. schedule. A better description of the noise...difficult to articulate. I though whirring was universal. Sort of like whistling into a oscillating fan? The whirring noise will track engine speed.

Cleaning the throttle body etc was also suggested to me. I had the techs check for the noise/shudder last oil change but of course they couldn't duplicate it. Air filter was changed last oil service(maybe I should check they actually put one in).

Seems strange a newish car in relatively light duty would need such an elaborate cleaning so soon. Any idea why a dirt build would occur after a relatively short period of time? Perhaps this is normal?

Thanks for the help

[ReTread]

Technically speaking instead of pressing on the gas, you are pressing 'on the air', opening a valve that allows more air to engine. The ECU through a series of sensor readings - throttle position, temp, o2, and others - adjust gas flow to the fuel injectors trying to maintain a stychiometric ratio of 1 part gas to 14.7 parts air. (cleanest efficient mixture ) More particulates, dirt, etc. are carried in outside air so fuel system parts in the air stream get dirty faster than in old carburated models. (you have plenty of dust around the prairies)

I have one brand of vehicle in which throttle body / injector cleaning is part of regular maintenance schedule. With the Echo just do it myself as a matter of course. (not even sure if it's in the user maintenance manual)

I don't suppose your whirring sound could be the electric fan kicking in? After 20 minutes vehicle might be warm enough to kick it in ....perhaps fluid temp related problem? If cooling temp sensor is faulty, ecu may be trying to go from open loop to closed loop condition and back if getting erratic temp readings? (and subsequent rich / lean problems)

I can't think of too much else except for alternator / air conditioner making a racket...

[Sully1]

There's a website called Sorensobrian.com that has a lot of diy fixes. Try cleaning the maf sensor, changing the pcv valve and switching to Shell gas. Also check out Echofans.com.

[chrissy]

i've been getting the same problem. not too concerned w/the idle dropping @ this point. but the whirring sound has been getting louder and starts when I hit 20mph. the servco dealer/auto service dept. is pretty certain it's something in the trans. very exspensive fix cause they have to take out everything. not sure if my warranty will cover, they'll find out when they take a look @ it (make sure no water got in first). my maintenance has been excellent...every 3.5 months since i bought my new car. it's a Yaris 4 dr. sedan, auto.

[Yaris Hilton]

Originally Posted by ReTread

Technically speaking instead of pressing on the gas, you are pressing 'on the air', opening a valve that allows more air to engine.

On a Yaris, you're not even doing that. There's no mechanical connection from the gas pedal to the throttle. A position sensor on the pedal tells the ECU how much power you want, and it figures out how much to open the throttle (and which gear to use with an automatic transmission.)

The whirring made me think of the fan, too.