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The mkiv Supra Owners Club

Engine hunting on startup/ idle


evinX
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Everytime I start the supra up and let it idle it wants to hunt, just under and just above 1k. Enough to drive me nuts. When I give it a rev it stops, as if some flow somewhere was blocked and revving it got the flow going. That's the best way I can explain it.

 

Ive done the following so these shouldn't be the case.

 

HT leads and plugs

Vacuum lines

Timing + crank pulley, bearing and tensioner

 

I want to check the ICV but the bolts are so soft they want to round off, and the bottom bolt is a pain to get at.

 

Anyone had this problem. Its getting unbearable now:(

 

thanks, Kev

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I had this same problem, had to grind little slots in the bottom pozi screw to remove it. I gave the valve a good cleaning and it was ok for a few months, but ocasionaly it starts hunting again, some times the engine cuts out completely and you loose all power steering and brake assistance, real balls ache, not sure how much a replacement valve costs.?

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I had this same problem, had to grind little slots in the bottom pozi screw to remove it. I gave the valve a good cleaning and it was ok for a few months, but ocasionaly it starts hunting again, some times the engine cuts out completely and you loose all power steering and brake assistance, real balls ache, not sure how much a replacement valve costs.?

 

https://www.autohausaz.com/toyota-auto-parts/toyota-idle_control_valve-replacement.html

 

2nd one, out of the 4 for a N/A. Ill get mine off eventually and see what I can do with it. If its a pretty simple assembly, all it should need is a clean in theory. If I were you its worth unscrewing it and cleaning it again

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Many thanks Evinx, The link told me what i did not want to know,lol, can you believe £280 for a valve, will make an extra effort now on fixing it, however cleaning is about all one can do, and if it does not work it is the transfer chip which is faulty, so may have to "bite the bullet" or look at breakers. ? It is not just the nuisence of the valve playing up tick over varying from 1,000 rpm to just holding on at 400 rpm, it can be dangerouse when the engine cuts completely, no power steering and little or no braking power.

 

11987078_1632854480308032_716917358447522141_n.jpg (115.4 KB)

11987078_1632854480308032_716917358447522141_n.jpg

Edited by herbiemercman (see edit history)
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We pulled my ICV today and cleaned it, and the butterfly valve. Its as if someone hitting the brakes as I want to drive, im leading towards my gearbox, just waiting on a part to come from the US before I service it. After the clean it idles fine, but sometimes if I rev it, it holds at 1500rpm. Im really just thinking of pulling the lot and dropping a new engine and box in. But that's only because im seriously Pi$$3d right now. LOL

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