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Ridiculous high idle

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Finally getting my hands back into sorting the gt and after fitting new fuel lines over the weekend I fired her up for the first time.... idle went straight to 3k 😂 I assumed vacuum leak so I had the inlet manifold back off as I'd recently removed it and assumed I'd left something. So that's all sealed back up cant see/feel any vacuum leaks whilst spraying carb cleaner around there with the engine running yet it still wont idle less than 2600 rpm.

The idle screw is wound all the way in and I've even disconnected the throttle cable so the throttle is as shut as it can be yet it still idles at that speed. Anyone got any ideas before I actually give up on the thing and strip it 

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You checked for vacuum leaks, but maybe theres a vacuum hose still unplugged? think of brake booster etc..

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2 hours ago, maerijn said:

You checked for vacuum leaks, but maybe theres a vacuum hose still unplugged? think of brake booster etc..

Yeah I've gone over everything like 20 times dude haha it's what I first assumed I'd done was leave one unplugged somewhere. Can't find anything.

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High idle is surely a leak or some sort of " extra " air passing through the throttlebody. try and remove intercooler pipe and block the inlet with your hand. the car should stall. if not its a leak. 

Give a quick check to your idle control valve too. might got jammed open

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3 hours ago, Duduglanza said:

High idle is surely a leak or some sort of " extra " air passing through the throttlebody. try and remove intercooler pipe and block the inlet with your hand. the car should stall. if not its a leak. 

Give a quick check to your idle control valve too. might got jammed open

Yeah I've had the icv off and cleaned it will give the throttle body a good going over tomorrow too

 

Cheers for the suggestions 👍

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Right... so with the engine running and inter cooler pipe off if I block the throttle body it cuts out. If I block the little vacuum hole inside the bottom of the throttle body it cuts out. It's also pulling alot of vacuum through that hole which tells me theres no vacuum leak. So to try eliminate that hole as its in front of the butterfly I block the vacuum lines underneath the throttle body, both of them. The car still runs straight up to 2600k. 

Even with those vacuum lines underneath blocked off I'm still getting vacuum pull through that little hole inside the TB so I'm guessing it pulls some from the other side of the butterfly theres not much I can do about that. 

I know my inlet is sealed fully as I had it back off the other day to check and sealed it with sealant along with the gasket.

Only thing I can think of is something has failed inside the TB that's allowing air to get pulled through that hole when it shouldnt be. I've had the TB off and can't see anything obvious though so who knows. I'll try pick up another TB

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Seems I've sorted it! Swapped with another throttle body I had hanging around and its dropped to 1600. Still a little high but the engine hasn't run in well over 12 months properly so I'm putting it down to that for now and we'll see how it goes 

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