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The mkiv Supra Owners Club

supra idles too fast?


BaileySupra

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hi, i have a small problem and that is my NA supra is idling too fast. if i rev it a little when its cold and then let it tick over again it ticks over at 2.5k but surges quite badly like it drops to around 1k then revs back up to around 2-2.5k. when they car is warm the car ticks over between 1.5k - 2k. when i turn the engine off and restart it it ticks over at normal rpm around 800-900rpm but then when i start driving it goes back to idling fast, what could this be :( its extremely annoying!! (P.S i hope you guys could understand my write up haha)

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How did this come about? Has it gradually gotten worse over time? Was it one day fine and the next day behaving like this? Did you do anything to the car before this started happening?

Could it be an air/vacuum leak? Knackered ICV? Did you touch/removed & replaced the TPS?

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A new TPS from Toyota is around £100 + VAT. A second hand one will always be a gamble. I wouldn't be replacing parts until you know which part is at fault. (You could spend alot of money and still have the same problem). Have you checked for air leaks on the intake manifold, etc? How's you oil level? As for lights not coming up on the dash, bulbs could have died or been removed to hide faults. I would personally disconnect the battery to clear all codes the reconnect it and go for a long drive so the ecu can relearn its info and gain any fresh fault codes.

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hi ,this sound like something similar to mine at the moment and iv tryed some of the above like, disconnecting battery 10- 15 mins to reset ecu; cheak air leeks: clean up idle speed control valve plus i have a spare one i tryed. it did help doing some of thos things but not solved it yet so i think il cheak for wirer connection earthing points over the weekend....

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Never had this issue on a Supra myself but did have a similar issue on a different car - turned out to be the coolant sensor. It wasn't registering it was getting warm so kept the idle speed and fueling up as if the engine was cold.

 

Just a wild stab in the dark seeing as the usual suspects have already been covered.

 

Also - although the IACV has been cleaned, it may still be worth swapping for a known good one to see if the unit is actually faulty.

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  • 3 weeks later...
I'm having the same problem here folks did you find what was at fault? I'm suspecting my issue is with the icv? If I use clarksons trick And give it a little tap, the rpm drops back to normal?

 

Car was running fine until I removed the tb?

 

Did you do anything with the throttle cable when the TB was removed? Is the cable adjusted properly?

Also, did the TB gasket get damaged when you removed/replaced the TB?

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I just solved this problem on my NA just bought. There were 2 problems at once: 1. Air leak in the intake system. 2. Distributor cap/rotor and spark plugs. To check the 1st one you can to buy an "Easy engine start" or "Cold start" spray from Halfords or petrol station (3-4 pounds) and spray it on the engine idling everywhere possible around the inlet manifold. If you feel the engine changing revs while spraying, try to find out exact place where revs are changing most when spraying and youll find the leak. It was a vacuum hose broken in my case, in some other cases theres an air leak through one of the inlet gaskets. After fixing this revs gone down from 2k to 1.2k. As it appeared bad ignition can also cause increase in revs, so i swapped Distributor cap/rotor and spark plugs from my other supra and it finally started to idle as it should.

I hope it helps!

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I think the throttle cable is ok, I cleaned the icv yesterday the best i could without removing the tb and gave it a run this morning, now the revs are not sticking as much but are still higher than normal, I will try the cheaper options first ie clean tb and icv properly this time and replace the gasket that's in desperate need of replacing!! Where can I get one of these from?

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I think the throttle cable is ok, I cleaned the icv yesterday the best i could without removing the tb and gave it a run this morning, now the revs are not sticking as much but are still higher than normal, I will try the cheaper options first ie clean tb and icv properly this time and replace the gasket that's in desperate need of replacing!! Where can I get one of these from?

 

Pop along to your local Toyota dealer they aren't that expensive. Throttle body gasket is £3.67 + Vat. Manifold gasket is £10.65 + vat and the final gasket is £9.14 + vat

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I think the throttle cable is ok, I cleaned the icv yesterday the best i could without removing the tb and gave it a run this morning, now the revs are not sticking as much but are still higher than normal, I will try the cheaper options first ie clean tb and icv properly this time and replace the gasket that's in desperate need of replacing!! Where can I get one of these from?

 

Have you tried adjusting the throttle cable?

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i did loosen off the securing nut for the throttle cable but it didnt help, after resetting the ecu and clocking a few miles its stopped sticking, but idles at 1k so at the weekend i will replace the tb gasket and give it a good clean again, this time cleaning out the channel where the idle control valve fits.

 

where can i find the torque settings?

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  • 2 weeks later...

image.jpgimage.jpg

 

Can anyone confirm if the throttle cable looks ok? There's abit of plastic showing is this normal? I cleaned the tb again which has completely cured the sticking idle valve but it still idles at 1k??

 

The only things I have done to the car is mount a fmic since I'm going na-t but can't see how that could be the problem.

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