Weird noise in engine bay

Jazza

Jazza

Active Member
Okay, I took a video of some weird noise i think may be coming from inside the throttle body? I don't know really.
It only happens when the key in the ignition is turned to ON. Sometimes the noise starts and after a few minutes or seconds it eventually stops, but in the video it just kept going. It's happened ever since I've owned the car.
So, any ideas?

[youtube]http://www.youtube.com/watch?v=2xVpQonzjJ8[/youtube]
 
wow doesnt sound good, i am probably way off, to me it sounds like something is stuck in your intake or manifold
 
So, the motor is running and your have traced that to the throttle body, yes?

If you're saying you hear it when the motor is not running, then it may be an IAC motor (electric motor hanging off the bottom of some throttle bodies) that has a bad bearing...

Maybe someone could tell me if a CE Lancer has an IAC (Idle Air Controller) motor... Most modern motor cars have a TPS and an IAC, newer cars also have fly by wire stepper motors, as they have no throttle cable.

If yours does have an IAC, put your hand on the black electric motor and feel if the rattling is coming from it.

If not, then sorry... I am just an old dumb bastard who continues to waste peoples' time...
 
87942m6_19.jpg


CE Lancer throttle body; showing TPS (at bottom), throttle linkage (at top) and IAC (on left).

Feel the motor on the left, when your car is making the rattles...
 
its a stepper motor that moves allowing air into the throttle at idle to keep the car running, tryg could be right, it could be slipping somehow, and jsut keep winding as its not yet reached its position. maybe. just maybe.
 
thanks for the info, not having a get up n go/hands on dad makes me such a noob with cars mechanically.

learn something new every day
 
Next question; to ascertain IAC fault, does your car fail to idle correctly, when the engine is hot and you change gear, do you get idle surge?

An IAC has to return to 'base' for start up, then step up to meet the engine idle condition; so if it's hot - it steps to a different length than when cold... If it is recycling quickly or has a stuffed bearing, etc, then you would get noises like that, potentially.

Additionally, could you tell us if that video was engine running or off, please.
 
Unplug it, if the noise stops then thats the cause and just get nother from a wrecker or just live with it if the car is still running fine!
 
tryg said:
Next question; to ascertain IAC fault, does your car fail to idle correctly, when the engine is hot and you change gear, do you get idle surge?

An IAC has to return to 'base' for start up, then step up to meet the engine idle condition; so if it's hot - it steps to a different length than when cold... If it is recycling quickly or has a stuffed bearing, etc, then you would get noises like that, potentially.

Additionally, could you tell us if that video was engine running or off, please.
Click to expand...

Engine cold or hot, it should still make that sound (the motor should still adjust itself) depending on the temperature of the engine.

Faults relating to the Idle Speed Control motor WILL cause cause a check engine light to appear. I believe from memory, after shorting out pins 1 and 4 right under the dash (with any old wire), if an error code has occured, it will be saved in the ECU memory and will flash in a series. The ISC error is 14 (one long flash, and 4 short pulses)
 
I am guessing Lilandonaki has had experience with a Lancer IAC... but no IAC should make a noise like what you are experiencing, I don't think that is what was meant.

I cannot say with clarity regarding Lancer CEL illumination with a faulty IAC, but I have seen this many times on Fords, and no CEL is evident with cyclic rattling on their faulty IAC. For the Fords, corrosion on the actuator arm leaves the plate floating and unable to withdraw. This leaves a too low an idle speed (for what the PCM is trying to mix-in) and a similar issue of the motor trying to recycle at high speed (although yours sounds quite different; like something loose and rattling against plate metal).

All the suggestions above, by Ryan and Lilandonaki will aid your diagnosis... your best friend when any electrical component fails is actually an Ohm meter.. if you have an OBD reader, so much the better!

Good luck.
 
tryg said:
I am guessing Lilandonaki has had experience with a Lancer IAC... but no IAC should make a noise like what you are experiencing, I don't think that is what was meant.

I cannot say with clarity regarding Lancer CEL illumination with a faulty IAC, but I have seen this many times on Fords, and no CEL is evident with cyclic rattling on their faulty IAC. For the Fords, corrosion on the actuator arm leaves the plate floating and unable to withdraw. This leaves a too low an idle speed (for what the PCM is trying to mix-in) and a similar issue of the motor trying to recycle at high speed (although yours sounds quite different; like something loose and rattling against plate metal).

All the suggestions above, by Ryan and Lilandonaki will aid your diagnosis... your best friend when any electrical component fails is actually an Ohm meter.. if you have an OBD reader, so much the better!

Good luck.
Click to expand...

I have a little bit of experience. Every so often i would get a CEL after (usually) highway driving then slowing to an idle. I eventually diagnosed it, and went to work fixing it. It turned out to be the throttle positioning sensor was off its factory position by mare mm's. However, by the time i figured that out i have pretty much my entire intake system apart figuring out what to do, and basically reset everything.

It IS meant to make a little bit of noise because its constantly adjusting itself.
Usually when you turn the key to IGN, it will sound for about 2 seconds, then stop. This is for the car to idle like normal cars do. After leaving the car for a few minutes (with key on IGN; can be second's not minutes too, depends really) it will sound for around 10 seconds, stop for a second, then sound for another 5 or so and then stop for another few minutes then repeat itself.

Jazza, if you can get yourself a Gregorys manual and a multimeter and read through why the sound is constantly happening. If it doesnt give any answer, then take the intake bits apart, and start "re-tuning" the ISC according to the Manual. Give yourself about 2-3 hours to fix it. And read through the manual for retuning a few times first
 
tryg said:
Next question; to ascertain IAC fault, does your car fail to idle correctly, when the engine is hot and you change gear, do you get idle surge?

An IAC has to return to 'base' for start up, then step up to meet the engine idle condition; so if it's hot - it steps to a different length than when cold... If it is recycling quickly or has a stuffed bearing, etc, then you would get noises like that, potentially.

Additionally, could you tell us if that video was engine running or off, please.
Click to expand...

Video was with the engine not running, just when I turned the key to ON.
When i start the engine cold it idles fine, about 1400-1500 rpm then drops to the normal idle speed, 700rpm. What is idle surge? When the engine is hot and i change gears nothing seems out of the ordinary.
And thanks, I'll have a look at that IAC and see if i can feel anything rattling.

lilandonaki said:
I have a little bit of experience. Every so often i would get a CEL after (usually) highway driving then slowing to an idle. I eventually diagnosed it, and went to work fixing it. It turned out to be the throttle positioning sensor was off its factory position by mare mm's. However, by the time i figured that out i have pretty much my entire intake system apart figuring out what to do, and basically reset everything.

It IS meant to make a little bit of noise because its constantly adjusting itself.
Usually when you turn the key to IGN, it will sound for about 2 seconds, then stop. This is for the car to idle like normal cars do. After leaving the car for a few minutes (with key on IGN; can be second's not minutes too, depends really) it will sound for around 10 seconds, stop for a second, then sound for another 5 or so and then stop for another few minutes then repeat itself.

Jazza, if you can get yourself a Gregorys manual and a multimeter and read through why the sound is constantly happening. If it doesnt give any answer, then take the intake bits apart, and start "re-tuning" the ISC according to the Manual. Give yourself about 2-3 hours to fix it. And read through the manual for retuning a few times first
Click to expand...

Sometimes when I hear the noise, it does just happen for a few seconds then stop. But other times like this time it just kept going. I could get a gregorys manual but i'd be so hopeless at taking the intake bits apart and "re-tuning" it, i wouldn't even know how to take my rocker cover off.. :oops:
 
Once the car is upto running temperature, turn your aircon on and see if it makes a noise. The idle speed motor (what ever you want to call it), will bump the idle when the aircon kicks in, so with someone else turning the aircon on and off should give you an idea if that is it or not.

As above, I would never rely on the ECU to diagnose faults, those codes are great to confirm a fault, but they will not always be present. As said above, it all depends how the fault arises if there will be a fault recorded.
 
Jazza2442 said:
tryg said:
Sometimes when I hear the noise, it does just happen for a few seconds then stop. But other times like this time it just kept going. I could get a gregorys manual but i'd be so hopeless at taking the intake bits apart and "re-tuning" it, i wouldn't even know how to take my rocker cover off.. :oops:
Click to expand...
Click to expand...

dont worry, ive never taken my cover off either, not would know what bolts to replace in what order :S

Actually, I think maybe, unplug your battery for about 10 minutes, then reattach it and start the car up. Let it idle for about 5-10 minutes, then turn the car off. Turn the key to IGN, and see if the motor keeps ticking?
 
ok 81gl, ill try that. i dont know if it will make the noise when the engine is running or if ill be able to even hear it.

today i went to to what tryg said and see if i can feel anything rattling at all, but it wouldnt make the noise. it only happened for half a second from when i turn the key from ACC to ON and back to ACC again and so on. So sometimes it does that, sometimes it goes for about 30 seconds and sometimes it just goes on and doesnt stop.

lilandonaki i recently got a new battery, so the car was unplugged overnight (cuz it wouldnt start anyway) and it still makes this noise before and after i got the new battery

And yea Ryan, my car's still running fine and it has been for 9 months now so might not be much to worry about.

Thanks for all the input fellas :D
 
welcome, sounds like it's intermittent...we all get a few seconds of sound (combination of fuel pump, solenoids and IAC motors), but when yours is doing Mambo Number 5, then you might be getting very poor fuel economy, a dying engine on gear changes, aircon turning on (as suggested above) or coming back to a stop from driving.

Until any of those things occur, then your IAC is doing enough to keep you going. There is no real rebuild for an IAC, the best bet (if it is in fact your issue) is to get a known-working second-hand unit from a wrecker; approx $90. A new one will set you back closer to $300, so just keep driving until you get those aforementioned symptoms.

Have no fear, I have had to replace two IAC motors over the years and several rheostat-type TPS modules on even newish cars I have owned.

Good luck.
 
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