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12-17-2012, 10:40 PM | #1 |
Drives: Yaris RS 2007 Join Date: Apr 2012
Location: Montreal
Posts: 10
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high pitch noise at idle
Hi,
I've waited a long time before posting about this problem trying to fix it on my own but now i'm at a dead end and im open to pretty much any advice, I have a 2007 hatch and when the engine is warmed up and i'm stopped at idle for about a minute I get a high pitch noise that comes from the engine bay. Ive tried to film it (http://www.youtube.com/watch?v=vTiOPe6qmAg), without much success.. It sounds like a vacuum leak but even when I sprayed starter fluid on the vacuum lines it didn't affect anything ...the car tries to stall and the engine shakes in a way i dont really like Then when the radiator fan comes on the idle goes up a bit and the noise disappears. As soon as the fan shuts down it starts again I look foward to your advice thanks |
12-19-2012, 10:40 AM | #2 |
1NZ-6spd
Drives: '05 6-Spd Vitz RS Join Date: Oct 2008
Location: Oshawa, Ontario, Canada
Posts: 2,967
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So you fixed it?
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12-19-2012, 11:48 AM | #3 |
Drives: Yaris RS 2007 Join Date: Apr 2012
Location: Montreal
Posts: 10
|
Not yet, still looking around for possible issues linked to that, i notice it runs lean when it runs badly, checked my upstream O2 and the resistances aren as specified in the repair manual so that might be it
have you ever heard of something like that? |
12-19-2012, 11:54 AM | #4 |
1NZ-6spd
Drives: '05 6-Spd Vitz RS Join Date: Oct 2008
Location: Oshawa, Ontario, Canada
Posts: 2,967
|
Have you checked to make sure the. Heat shield isn't loose. It'll make a squeaking sound like that.
And you need to check voltage on the front sensor not resistance to determain your reading. |
12-19-2012, 12:42 PM | #5 |
Drives: Yaris RS 2007 Join Date: Apr 2012
Location: Montreal
Posts: 10
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the repair manual states the values in Ohms not in Volts and the heat shield does not move at all
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12-19-2012, 12:50 PM | #6 |
1NZ-6spd
Drives: '05 6-Spd Vitz RS Join Date: Oct 2008
Location: Oshawa, Ontario, Canada
Posts: 2,967
|
Those resistance values are for an unplugged sensor to make sure it's within static value. Those are not for when the car is running plugged in. So in order to read rich or lean you need to measure the output voltage of the sensor.
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12-19-2012, 02:05 PM | #7 |
Drives: Yaris RS 2007 Join Date: Apr 2012
Location: Montreal
Posts: 10
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That's exactly how i tested it, engine off and in my garage, so i was around the 20 degrees they recommend for testing. The car seems to run lean when it tries to stall my obd2 with bluetooth to my phone reads 15.5-16 when it makes the noise and stalling
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12-19-2012, 02:38 PM | #8 |
ULTIMATE
Drives: 09 5dr LB, 2x 08 3dr LB Join Date: Oct 2008
Location: USA, CT
Posts: 13,460
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The ECM maintains a constant voltage on the sensor and it measures the current required to maintain that constant voltage to determine AFR. So, if you measure the voltage on the sensor it will always read the same unless there is something wrong with the circuit within the ECM.
__________________
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12-19-2012, 02:57 PM | #9 |
1NZ-6spd
Drives: '05 6-Spd Vitz RS Join Date: Oct 2008
Location: Oshawa, Ontario, Canada
Posts: 2,967
|
I guess I'm not up to date with how the Yaris ECU works, just the Echo.
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12-19-2012, 05:52 PM | #10 |
Drives: Yaris RS 2007 Join Date: Apr 2012
Location: Montreal
Posts: 10
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If I unplug the AFR meter on the exhaust manifold I'm assuming that the ECU will switch to fault mode and run from a baseline set by Toyota ? If so, if I unplug it and the car runs fine it just means that I have to change the sensor?
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12-19-2012, 10:48 PM | #11 |
Drives: 2009 5-door, 5-speed Join Date: Sep 2011
Location: White Rock BC
Posts: 687
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Hard to tell much from the video. Try hitting the exhaust with your hand or a soft mallet. See if you get any rattles. Also while cold, take your finger and pull on the manifold heat shield etc and try to "twang" it like a guitar string to get a noise. Often the best way to find loose heat shields. Just watch for sharp edges.
Other things that come to mind: -cracked exhaust -plugged cat or broken baffle in muffler causing intermittent plugging (but would expect to notice this driving, not at idle) Any other engine problems with the car? Is it stock? |
12-20-2012, 12:21 PM | #12 | |
Drives: Yaris RS 2007 Join Date: Apr 2012
Location: Montreal
Posts: 10
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Quote:
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12-20-2012, 12:27 PM | #13 |
1NZ-6spd
Drives: '05 6-Spd Vitz RS Join Date: Oct 2008
Location: Oshawa, Ontario, Canada
Posts: 2,967
|
Ok, I have another idea... I too ran a straight pipe axle back for a while and tho it was cool and loud, It also set missfire code because the joint was loose, at idle. Make sure all the joints in the exhaust system are tight. It was doing the exact same thing at idle, minus the noise. The revs were dropping because it was pulling timing back.
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12-20-2012, 10:50 PM | #14 |
Drives: 2009 5-door, 5-speed Join Date: Sep 2011
Location: White Rock BC
Posts: 687
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Ok. Leaking exhaust before, or sometimes up to a foot behind the pre-cat O2 sensor can suck in oxygen and confuse the computer. Also rattles can be picked up by the knock sensor, which will then cause the computer to pull timing out. Either could cause the poor idle issue.
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12-21-2012, 01:07 PM | #15 | |
Drives: Yaris RS 2007 Join Date: Apr 2012
Location: Montreal
Posts: 10
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Quote:
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12-21-2012, 01:09 PM | #16 |
1NZ-6spd
Drives: '05 6-Spd Vitz RS Join Date: Oct 2008
Location: Oshawa, Ontario, Canada
Posts: 2,967
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try re-installing the stock muffler and see if that fixes the problem. Maybe the knock sensor is overly sensitive.
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12-21-2012, 02:58 PM | #17 |
Drives: Yaris RS 2007 Join Date: Apr 2012
Location: Montreal
Posts: 10
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12-21-2012, 11:03 PM | #18 |
Drives: Yaris RS 2007 Join Date: Apr 2012
Location: Montreal
Posts: 10
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Is there any way to bypass the knock sensors for testing purpose?
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