Can't fix high idle problem

Hi people.

I need more help please. I've read and applied all the normal fixes to solve the high idle problem, but it is still around.

The problem is NOT constant. The car will drive great for a weak or sometims a few days, then the high idle will be there when you start the enjin.

I've cleaned the whole intake area and sensors with Carb cleaner and contact cleaner. I've replaced the IAC valve and TPS sensors. I had someone with an expensive diagnostic tool, which did not show any errors even after running the car for hours.

The idle will go to 2000 or 3000 rpm when the car starts. Sometimes it goes away when switching off other times is doesn't.

What I know is when I pull out the TPS sensor's plug, the idle returns to normal and then I plug the power back in it stays normal. I don't know if the throttle body itself is doing it.

What else can I check out? Thanks

Maybe intermittent air intake sensor?

Your in south africa? Your car is quite a bit different than ours.. First, you have a throttle cable right? so this issue isn't a DBW issue. What kind of intake sensor do you have? MAP, MAF, or what? IAT sensor (mentioned) could be at fault?

High idle is potentially your temp sensor, or your AC as an issue. Try turning your ac on and off and see if that effects the idle. If it is the temp sensor, it is in "winter" mode and the car is adding fuel until warm up occurs. IIRC, the winter temp is on an open loop circuit, so if you have a good scan tool, you should see it is still in open loop. Open loop does not set codes in most cars, hence why you had no codes. And if you have live data, compare the temp to actual. If you can't do any of that, just replace the sensor and see if that fixes it.

Hi Petrified Rabbit. Yes, I'm in South Africa. Thank you so much for that. I will try to do that. Is it the one just after the air filter inside the black tube before the throttle body? I will replace it and see what happens. Yes, it has a MAP sensor at the back of the intake area. Will try to include a picture.Attachment 11121

Is this were the air temp sensor location is?

Attachment 11122

And this is the MAP sensor I think

Attachment 11123

Quote:

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Originally Posted by Martin1971

Is this were the air temp sensor location is?

And this is the MAP sensor I think

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You are correct.

Thanks Daox. Will change and repost this week or next week, giving it time to check out.

Hi, I'm back and replaced the air temp sensor, but still same problem. I have noticed something very interesting that I want to check out. The connector at the TPS. This is why I suspect the connector:

1) When the car idles high, I pull out the connector and put it back in. Engine light is on, but car idles great, maybe because the ECU sets a default value for the TPS??

2) When the car idles high, I turn off the engine and start again. Still high idle. I turn off the engine and unplug the connector at the TPS and put it back in. Start the car and its fine.

There should be no power on the connector when I turn the car off. So, how is it that the car idles OK every freaking time I unplug and plug back in??? Doesn't matter if the engine is running or not!

Am I on the right track? The high idle is random. Will be okay for a day or two, then Bam it's there. Then I plug out and back in, then it's fine for a week or few days, then Bam back again.

The engine becomes very smelly hot because of the high idle. I want to fix before summer is here. Engine temperature does stay constant though, just below the halfway mark.

I forgot your are in the winter months, have you tried checking the throttle body to see if it needs cleaned?

Looking at the picture, that solenoid on top of the throttle body, could probably be stuck open, letting too much air in. I have replaced a few of those on older cars, saturn maybe? I do not know if that is what you are unplugging or not. I am looking over your engine trying to compare it to something I have worked on..

Okay, I replaced the air temp sensor, air control valve and tps sensor. I've cleaned the throttle body a few times. But I must admit, I didn't remove it. I just loosened the air intake and sprayed the intake with carb cleaner and wiped with clean cloth.

So I've checked the connector and wiring a bit down the line but don't find any fault. Any new ideas are welcome... Thanks

I would have checked/replaced the COOLANT temp sensor & wiring before the intake AIR temp sensor.

It likely has a bigger effect on idle speed via the computer.

Thanks MetroMPG

Another thought: I wonder if a stuck-open thermostat could cause this? Coolant not coming up to temp.

It could be the thermostat, but it wouldn't it idle normal at first and then climb as engine warmed/didnt warm..?

Did you check all the typical issues, like torn intake boot, vacuum leaks, etc?

Hi guys. Thanks. Yes, I looked at the vacuum tubes today, don't see any leaks. Tested with air in a tin and fine spray water.

Battle to find vacuum problem. Must admit, I lack experience in this department, but what I've checked doesn't lead to a vacuum leak. Can this be an ECU problem perhaps?? Thanks

Okay, guys. Today with the high idle I had the car checked out again with the diagnostic tool - no error. The technician and I were talking around solutions and we hit the Cat converter with a hammer and emediatly the revs dropped. Was fine with a 10km drive and then high idle back again. Slam the cat again and back dropped the idle. My question now is, can a clogged cat cause high idle? Wouldn't it rather cause poor idle?

Quote:

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Originally Posted by Martin1971

Okay, I replaced the air temp sensor, air control valve and tps sensor. I've cleaned the throttle body a few times. But I must admit, I didn't remove it. I just loosened the air intake and sprayed the intake with carb cleaner and wiped with clean cloth.

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Hi did you ever fix the problem? My 2004 aveo has the same problem

I would like to know if you found the solution to your problem

Quote:

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Originally Posted by Eddievee

I would like to know if you found the solution to your problem

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Hi Eddievee
I seem to have multiple problems that caused the problem. First the TPS sensor was broken. After replacing it, the problem returned. We found the Catconverter was blocked. I opened it from the bottom and removed the inner parts. I believe they make it from Titanium or some expensive metal. After a while it started again. I replaced the Lambda sensor. Some call it the Oxygen sensor. It's just above the Catalitic converter. After that all was sweet!!! So it seems there was a few things that failed and caused the problem. It's all fine now. Hope you get sorted.

Awesome! Thank you for the quick response! I've also changed the tps sensor, changed the IAC valve and cleaned the throttle body. I will now try to change the o2 sensor and have the converter checked. Thanks again!

Pleasure buddy. Please let us know if you got sorted.

Good day Daox, Petrified.Rabbit, Martin1971, MG admin and Aveo drivers with this similar issue/problem.

guys, i hope all is well. i have been facing the above said problen with my aveo 1.6 e-tec 2 auto trans. i have not found the cause or problem, i have replaced the TPS ( throttle position sensor ), Idle air contraol Valve and sensor, air temp Sensor, thermostat, and have removed and cleant the throttle body, to brand new standards. this allowed the vehicle to idle at 0.900 for roughly 2 to 3 days, before returnig to the usual high idle, and being an auto, it is difficult on the road, for many reasons. i have left the vehicle to warm up for over 30min and still high idle. started, switched off, and on again. tramped the gas pedal as hard as possible, everything. i even press the hold button to prevent accidents, but yet, i am sure it will damage the gearbox.



recently my vehicle stalled, whilst travelling, and had to bring the vehicle to a halt, inorder to restart.

the vehicle proceeded to do so, until i removed a thin air pipe sucking air from the vaccum ( im not too sure if is is a vaccuum) but it controls the butterfly flaps within the manifold, and i have blocked this pipe, which is now allowing the vehuicle to drive without stalling. this pipe runs from this "vacuum" to a cylndrical component against the firewall, which has a sensor, and another pipe, running to an inlet on the manifold.

i have had this vehicle diagnostically tested numerous times, and no faults are picked or shown. i have even replaced the entire plastic manifold, which the throttle body is connected to.

please, my questions are, if anyone can help, as i prefer to do my own repairs:

please please please

(1) what is the correct termonology for that cylnder with the black pipe controlling the vacuum for the butterfly flaps?

(2) could that cylinder be at fault, including the sensor?

(3) i know others have solved the same issue, but only for a length of time, but has anyone fixed the problem wihtout the high idle returnning?

(4) could the EGR ( exhaust gas reconciliator ) be a possible cause of the high idle issue ?



kind regards

red lemon

(as my aveo is red, and i think its a lemon)

Hi, try to remove the insides of the catalytic converter. Could be blocking the airflow. How much miles / km on the clock?