philwaters Posted September 7, 2001 Share Posted September 7, 2001 Hi, A question on behalf of a friend at work. He has an Elise that has started to suffer from a sticking throttle. He says that it is pretty intermittent, but the engine revs drop to around 2500rpm and he has to blip the throttle to get them to go down again. I suspect the cable may have a kink in it or just some dirt, but is there anything else he can check or that might be causing this (ECU, throttle sensor etc?) I'm going to have a look for him at lunchtime, but other than the cable not sure what to look at on one of these modern things smile.gif Phil Waters The car in front must be less in control teeth.gif Link to comment Share on other sites More sharing options...
Fast Westie Posted September 7, 2001 Share Posted September 7, 2001 Phil Sounds like the idle bypass valve is sticking. This is controlled by the ECU to set the idle speed. The car in front is a Westfie1d wink.gif Link to comment Share on other sites More sharing options...
philwaters Posted September 7, 2001 Author Share Posted September 7, 2001 Cheers, I don't suppose you could point me in the right direction - what does it look like, where abouts is it located on the engine, etc? Is there anything I can do without tools, mine are in the 7 at home and his...well its an Elise owner (that'll start a row or two teeth.gif) Phil Waters The car in front must be less in control teeth.gif Link to comment Share on other sites More sharing options...
CHRIS CLARK Posted September 7, 2001 Share Posted September 7, 2001 If the engine 'hangs on' the revs for a short while until settling into an idle I would suspect a worn/dirty throttle pot. This certainly fits the bill (but like most modern engines, so could a few other things too!!!). Link to comment Share on other sites More sharing options...
Mick Day Posted September 7, 2001 Share Posted September 7, 2001 Idle bypass valve: electrical thingy, probably stuck onto the plenum chamber with wires sticking out. Could be a MEMS problem. Mick Day Link to comment Share on other sites More sharing options...
Tony Martyr Posted September 8, 2001 Share Posted September 8, 2001 Phil: The IAV is so often the cause of complaints about the throttle sticking open it should have a forum of its own. It is easy if a little alarming to check if the throttle butterfly is shut when the engine is staying at higher than idle revs. If so the air that is fueling the engine is bypassing the butterfly via the Inlet Air Valve. It has a punger valve in it that the moved back and forth by the ECU based on the manifold air temperature. I suggest you locate the valve, it lies at an angle across the throttle valve the opposite side from the cable quadrant. It has a plug with two cables at the back which should be simply unplugged when the engine is warm and idling at the correct speed. You will have thus locked the spool in the correct place for warm idle. You will have to warm the engine up on a cols start before it will idle well but if the problem goes away you can buy another - I wouldn't bother as it is only needed at MOT for emission correction at idle. Link to comment Share on other sites More sharing options...
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