Can't fix high idle problem

[Martin1971]

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

[Martin1971]

Maybe intermittent air intake sensor?

[petrified.rabbit]

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.

[Martin1971]

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.

[Martin1971]

Is this were the air temp sensor location is?



And this is the MAP sensor I think

[Daox]

Is this were the air temp sensor location is?

And this is the MAP sensor I think

You are correct.

[Martin1971]

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

[Martin1971]

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.

[petrified.rabbit]

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..

[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.