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The mkiv Supra Owners Club

Sequential problem back :(


Shane

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So some time ago I posted I had a sequential problem with the car. Looking at Ian C's write up it sounds as though all boost is being lost through No.2 due to the EGCV not opening. Basically No.1 boosts up lovely, then sometimes (and that's what makes it hard to trace) at the point where you would expect No.2 to come online I lose boost all boost already generated from No1 and it goes flat. I thought I had cured it by replacing the EGCV VSV and replacing almost all the pipes with decent hoses.

 

But last weekend it did it again twice on the strip, now of course its running just fine again and acting just like a normal BPU set up should.

 

So, just been having a careful look at it again and I noticed hoses to and from the stock re-circ valve are a bit tired and where i have a bit oil in my intake due leaky seals that there has been some oil weeping out from the joints of the valve and the joints are not at all sealed properly. I will pull this off later and give it a clean and replace the hoses, assuming I am losing pressure from these connections, could this be the sequential problem too? I have studied Ian's explanation and I would think not, but curious to know your thoughts.

 

The only other hoses that have yet to be replaced are the ones to and from the vacuum tank which I havent done as I need to get the car in the air really, unless there is an easier way?

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Guest gbraen

Had the same problem with my engine and found a leak in the hoses to the vacuum tank nearby the rear turbo. Check these. Almost impossible to reach. The tubes the hoses goes into is mounted on the firewall and when the engine moves they will get stretched and will tear apart after all these years.

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Had the same problem with my engine and found a leak in the hoses to the vacuum tank nearby the rear turbo. Check these. Almost impossible to reach. The tubes the hoses goes into is mounted on the firewall and when the engine moves they will get stretched and will tear apart after all these years.

 

OK thanks. Yes these are the only ones I haven't replaced so I guess they need taking out of the equation, but they are almost impossible to see/get to.

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Well just replaced the two pieces of hose to the pressure tank, wow that's tight down there. Will tackle the other two on the turbo side tomorrow if I get chance. They look even tighter.

 

If you talking about the ones to the pressure tank near the firewall, good luck.. I tried top, bottom, ended up taking the gearbox out to get to them..

 

Hope you come right..

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If you talking about the ones to the pressure tank near the firewall, good luck.. I tried top, bottom, ended up taking the gearbox out to get to them..

 

Hope you come right..

 

Yep they are the ones, I managed to replace both to the pressure tank on the inlet side tonight and will tackle the two at the other end at the turbo side tomorrow. By loosening up the loom where it goes through the bulkhead and taking the transmission dipstick out you can just weave your hand in, but I have suffered some serious scratches to my arm in doing so. No pain no gain. Thinking to take the inlet pipework off to number 2 to give a bit more room to do that side maybe.

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Yep they are the ones, I managed to replace both to the pressure tank on the inlet side tonight and will tackle the two at the other end at the turbo side tomorrow. By loosening up the loom where it goes through the bulkhead and taking the transmission dipstick out you can just weave your hand in, but I have suffered some serious scratches to my arm in doing so. No pain no gain. Thinking to take the inlet pipework off to number 2 to give a bit more room to do that side maybe.

 

I removed idle control valve piping and turbo number 2 inlet pipe, it was still tight but doable.

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