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The mkiv Supra Owners Club

N/A High idle speed


Guest SilverSup
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Guest SilverSup

Hi guys.

Could anyone tell me a possible cure/cause of fault for a high idle speed on an N/A when it's cold. Mine seems to idle around 2k rpm when cold started, but slowly settles down after 10 mins or so. I've seen others run around 1200-1500 rpm cold start and wondered if mine has any major problems?

 

Engine is stock aside from a kakimoto cat-back exhaust.

 

Thanks fellas :thumbs:

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Mine idles at about 1600-1800 rpm when I start it cold to and like you said it goes down after a couple of mins but if you drive it when like this it feels like you are being dragged along. I thought it idled high so the oil temp gets up quicker although I am probably wrong. I found when the ecu was reset and left to run on its own for a few minutes without touching the throttle and then driven for a few miles carefully the next time I cold started my car it seamed a lot better.

I hope you do get a answer because I will have a play about with mine if it turns out it is wrong.

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Guest SilverSup
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As long as it settles down to around 700-750rpm when warm, all is well.

 

But after cleaning the ICV and confirming there are no vacuum leaks from hoses or gaskets, if you can't get the revs down to this number you may find the throttle body is worn and leaking in air.

 

Try swapping on a t.b. with less miles on it.

Edited by David P (see edit history)
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Mine is at 2K as well on cold start, it's perfectly normal. I believe this is called fast idle so then the engine/oil & cat temps can get to operating temperature quicker.

 

I have a very low mileage engine & it does the same so I wouldn't worry. It's only if it is stuck on 2,000 RPM or cold starts on 4K then you should be worried.

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Guest SilverSup

ok cool. Yes, mine settles down to around 700 ish when warm. I just had a bad feeling that i'd gone and bought a lemon after only a few weeks of ownership.

Thanks for the help fellas :thumbs:

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In my defence we were almost there with a decision about what may or may not be wrong, Plus you can tell how credible someone is by other little gems like that video. On that basis and Abz advice weighted against my high idle and Abz drag career I have decided to sell my car just to be on the safe side :D

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In my defence we were almost there with a decision about what may or may not be wrong, Plus you can tell how credible someone is by other little gems like that video. On that basis and Abz advice weighted against my high idle and Abz drag career I have decided to sell my car just to be on the safe side :D

 

Lol I'll like that logic :D

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:D

 

I was wondering who would win a drag race between this group, Add your own suggestions too.

 

1) Abz image

 

2) Kayla avatar13554_8.gif

 

3) Stephen Hawkins (Favourite) image

 

4) Penelope Pitstop http://t1.gstatic.com/images?q=tbn:ANd9GcQ5djmVpHfq2fOXB5RpOcWQ7XfJYPXbXn3IU5xl9D-Hzlp2vLWV

 

5) Mr Magoo image

 

6) Dick Dastardly http://media.giantbomb.com/uploads/2/23286/1079647-meanmachineani_thumb.gif

 

7) Lewis Hamilton image

 

8) Bear and glacier image

 

9) My NA aerotop image

 

10) Andy image

 

11) Neil NA image

 

12) Fred Flintstone image

Edited by Graham1984
Forgot neil (see edit history)
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N/A idle speed is now a bit of a nightmare. Basically if it idles too fast it's getting too much air. or the throttle position sensor is giving incorrect feedback to the ECU. An air leak could be external air traceable with a propane jet lance, or the idle speed control valve is malfunctioning or getting duff control signals from the ecu. The throttle body itself is prone to wear. It's ESSENTIAL that only the matching part number throttle position sensor is used if that's faulty, and it need setting up to perfection. Finally the engine needs to be sending correct water temp signals to the ecu that change in correct relationship with the actual engine water temp, The problem is most N/A throttle bodies are now warn and a new TB is about the price of another N/A car... ;) If you mess with the paint sealed throttle plate stop screws the TB is pretty much bin material unless you are VERY lucky.

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