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The mkiv Supra Owners Club

Inlet butterfly valve problem/issue. Help required


Graham1984

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My car is running really strangely at the moment, I know when you get to around 4k revs the inlet manifold valve opens and gives you a kick of power but for some reason mine is getting to 4k revs and revs fast up to around 5k but with no gain in speed and then settles back to 4k and the car then somewhat decides to go which before it had a slight delay but nothing like what it is now.

 

Has anybody got any ideas at all as to what is causing this or what I could do to solve this as frankly it is peeing me off. I have searched this forum but nobody seems to have the same problem as what I am it is almost like a clutch slip moment when the revs shoot up but not the speed.

Edited by Graham1984 (see edit history)
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If the revs are rising without gaining speed then the clutch is slipping. To test accelerate in say 4th/5th gear from 20-30mph, this will put the clutch under load and you'll see/hear the revs rise without drive to the wheels.

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If the revs are rising without gaining speed then the clutch is slipping. To test accelerate in say 4th/5th gear from 20-30mph, this will put the clutch under load and you'll see/hear the revs rise without drive to the wheels.

 

Sorry Nic I should of put that I have tried that but it just accelerates slowly but with the same increase in speed and the revs which makes me think it can't be that, I will test that again tomorrow just to make sure but this problem is cheesing me off and it only does it around the revs for the inlet valve opening and no when else. Maybe it is just dirty and getting stuck or something of the sort.

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I just went and tested it to confirm the clutch was not slipping and as Nic said to do 20mph in 4th and it was fine and the revs didn't jump up at all and went up gradually with the speed. I have tried dropping it down a gear or two so 60mph in 3rd ect and it only happens now and then and must of been more just having a funny moment earlier.

 

Would all the above point to the inlet valve being dirty or not opening properly sometimes or just anything along them lines?? If there is a guide as to how to take it apart apart to check it or even what to look for so I can get a mate to check that would be great as it just bugs me when the car doesn't work as it should as it seemed to just accelerate through the rev range fine a minute ago where as before it was playing up.

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Would this be the cause of intermittent problems then? I will check anything I can see tomorrow for splits ect as I have no idea about what is what or what to look for minus a hose not on or a obvious split/hole.

 

I wish I was not so useless but thanks for your help David :thumbs:

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So would I be looking to check the little catch on the side of the inlet manifold moves (Pulled down) when the engine is revved? Also I guess just check for any split pipes I can spot I suppose, Sorry to be a nightmare I am crap with this sort of thing, My car did have a high idle as well at start up although I thought that was normal on NA's.

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