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The mkiv Supra Owners Club

faulty IACV?


J_Supra_07

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I have the problem of the seconded turbo not boosting. I have already checked the turbo out.

I had time on my hands 2day so I striped the egcv off, and checked it over.

All appeared to be in order. So I had time so striped everything off turbos also. Seconded turbo is in good condition. I have put it all back together again and still no seconded boost.

I believe it’s the IACV.

Would others agree?

 

Thanks

jason

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I had a problem with no second turbo and it was quite intermittant, which made it awkward to find the problem. Mine turned out to be the IACV vsv. My symptoms were full boost on first turbo (about 11psi) then as the revs reached 4k rpm I noticed the exhaust note change slightly but no increase in boost or power just the same 11psi. When I checked the resistance across the vsv it was fine and always opened when I put 12v across it so it tested fine. Once I replaced it though the problem was gone.

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Check the 2 very small vacum pipes down the back of No2 turbo, they are about the size of washer pipe and you will need a pair of long nosed pliers to get to them, try swapping them over, if they are on the wrong way round you will get no No2 turbo.

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Why not?? Its a common cause for number 2 not working correctly

 

Sorry guys, misread the acronym. I always refer to the idle air control valve as IACV,its actually known as the ICV which is nothing to do with the sequencial system.

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I had a problem with no second turbo and it was quite intermittant, which made it awkward to find the problem. Mine turned out to be the IACV vsv. My symptoms were full boost on first turbo (about 11psi) then as the revs reached 4k rpm I noticed the exhaust note change slightly but no increase in boost or power just the same 11psi. When I checked the resistance across the vsv it was fine and always opened when I put 12v across it so it tested fine. Once I replaced it though the problem was gone.

 

Sounds exactly the same as the problem on mine, just got to get an IACV VSV

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