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The mkiv Supra Owners Club

None-descript engine issues...


Guest philclark1985

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Guest philclark1985

Hi guys, I'm having an on-going battle with my newly purchased NA:

 

It was originally idling at 3500 rpm, until I discovered that revving the engine hard was actually causing the "throttle position" screw to loosen and as such, push the idle up to about 4000 (coming to a junction after the motorway was awkward!)

 

I have completely removed this screw for now, until I can find a better fit in the coming days. This has dropped the idle to 2200, but still can't get it below this. In 1st and second gear, the car accelerates on it's own until it hits 2200 revs. Oddly though, there's no such issue in 3rd...

 

Any advice on this issue? ( I have already cleaned out the icv using the very useful thread in here... Thanks guys!)

 

Secondly, there seems to be a build up gathering around the edges if the manifold. Looks oily/ like fuel perhaps. Could this be due to the above issue, or do I have bigger fish to fry?

 

Any advice will be hugely appreciated. As you can tell, I'm new to dealing with my own technical issues but more than willing to learn and have a go at sorting it myself...

 

Thanks in advance.

 

Phil

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Remove and clean with petrol or brake cleaner the idle control valve and the throttle butterfly plate and housing. Renew the crankcase PCV valve and sealing washer. Look for any small hoses around the plenum that may be split, off loose or deteriorated to the point they may leak. If that doesn't fix it check the throttle pot setting is EXACTLY as it describes in the workshop manual. that may be daunting if you are new to electro-mechanical work. In 90% of N/A's idling too fast it's due to excess air entering the engine intake somewhere.

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  • 3 weeks later...
Guest philclark1985

HI Guys,

Thanks for the advice, got myself a workshop manual making it's way to me so should be able to have a crack at this in the coming weeks. Also enlisted the help of another member so with any luck, I may have it runner a bot smoother shortly...

 

Thanks again!

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