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Jap Turbo - TTC back to Seq not running 2nd Turbo


Shaleskin

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When I purchased the car with dead turbo's a few months back it had been setup in the temp TTC way.

 

Only recently wanted to change it back as i'd like to have it running as it were intended to be.

I've removed the VSV's and tested them directly to the battery with a piece of tube blowing through to make sure they are moving inside when power is put through them, both the IACV and the exhaust for the 2nd turbo click and allow air through.

Put them back on the car, plug the plugs into them, plumbed the piping up to how it should be and all I can get is 5psi running on the 1st turbo, 2nd turbo doesn't come online at all.

 

If I go back to the TTC way, I have to get it to 3psi or so and when i come off the throttle you can hear the actuators have been opened (exhaust is silly loud on blitz nur spec) and will stay like that for quite awhile even after the car's been turned off and will boost upto 1.2bar, afetr 4k revs.

 

What else should I check for?

 

(Jap turbo's and auto)

 

Thanks :)

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This thread may be of help if you've not seen it

 

http://www.mkivsupra.net/vbb/showthread.php?27904-Sequential-turbo-problems

 

Thanks for the link, although I've read through it and although it says the IACV isn't opening, neither is the exhaust side of it as I can tell when it opens due to the sound difference.

 

Really am stumped as I've checked directly to the battery that the VSV's work but can't get them to function :(

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I think I'll get some new hoses and start from scratch as I cannot get it to run the 2nd turbo :(

 

Also noticed I'm missing the reed piece in the housing. It's just 2 open holes, will this cause any damage if I do get it in sequential again?

 

I did have a thought though;

 

If I ran both IACV and exhaust VSV (mechanical bits not the electrical switches) directly to a feed from the inlet (behind throttle body) so it see's both + and vacuum would this not cause it to open and close but with better low down grunt as I've been running it TTC since purchase. Or would this just cause it to brake something as I imagine it would be constantly opening and closing the valves everytime it saw slight pressure?

 

Thanks for your feedback :)

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Ok, have found my reed bits and have put it back in after drilling the screws out as they broke (originally why I removed it completely) and re-plumbed the hoses up for sequential with the old hoses. New hoses were dispatched today but I have progress!

 

1st turbo is hitting 10psi by 2800rpm or so compared to TTC at much later and holds until redline... 2nd turbo isn't coming online at all though. I've tested all the VSV electronically while blowing through which they all do as they should. I can only assume the hoses are leaking? Even though in TTC it'll boost to 16psi after 4k everytime?

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Ok, have found my reed bits and have put it back in after drilling the screws out as they broke (originally why I removed it completely) and re-plumbed the hoses up for sequential with the old hoses. New hoses were dispatched today but I have progress!

 

1st turbo is hitting 10psi by 2800rpm or so compared to TTC at much later and holds until redline... 2nd turbo isn't coming online at all though. I've tested all the VSV electronically while blowing through which they all do as they should. I can only assume the hoses are leaking? Even though in TTC it'll boost to 16psi after 4k everytime?

 

If you get 1.1 bar in TTC mode then you know for sure it ain't the turbos.

So the only thing you can do like you said is to replace the hoses and hope it solves it. The sequential unit complicates things because its hard to pin point which part goes wrong.

 

But I guess its all down to elimination, check hose, check VSV.

 

Last thing to check is the pressure tank which needs the inlet manifold removing but check with all the easy options first.

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If you get 1.1 bar in TTC mode then you know for sure it ain't the turbos.

So the only thing you can do like you said is to replace the hoses and hope it solves it. The sequential unit complicates things because its hard to pin point which part goes wrong.

 

But I guess its all down to elimination, check hose, check VSV.

 

Last thing to check is the pressure tank which needs the inlet manifold removing but check with all the easy options first.

 

Correct me if I'm wrong but I thought a quick test with the pressure tank is after you've driven in TTC/Seq you pop the pipe off going to the IACV from the main pipework and you hear air rushing in/out then the tank is OK. As mine does this, or even when I'm in TTC, it'll still be on TTC (temp way) even after a hour or so getting back into the car without having to pressurise the system again to open the exhaust and intake valves.

 

Since buying this 3 months ago with dead turbo's I've been wanting to go single but would like to see what the sequential can do before I do the swap over in the next few months :)

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Any suggestions where I should look next? Boost up to 10psi give or take and around 4600 rpm or so it'll drop to 8 or so and by 5300rpm the 2nd turbo just springs to life.

 

Now this says to me it's not pre-spooling the #2 turbo, where should I go from here?

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  • 1 month later...

Reviving this thread as I've tested the pipes with a pressure tester.

 

I;ve also done the Stu Hagen #1 mod recently so the EBV has a seperate feed going to it now. No leaks on the pipe work, pressure tank holds it's pressure for a good few minutes. Have previously tested the VSV's and they work as they should.

 

What I did notice is the EBV doesn't open with anything less than 20psi. If I pressurize it with anything less it just doesn't budge. Holds its pressure for a few minutes too so there's no leaks. Did have a quick look for "Spacers" or anything obvious that may be interfering with it.

 

I'm honestly stumped as I've read it's meant to start opening at 10psi but mine doesn't. Has anyone else had this issue with the EBV actuator?

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Well, that cannot be right, as a stock 2JZ-GTE won't make anything like 20 PSI, which would make yours redundant. I would change it, or check there's no resistance from the butterfly.

 

I've got another to try from my old dead turbo's when I can pick them up later today. If that works without an issue I'll swap them over next weekend, I take it to test that there's no resistance from the butterfly it requires removing the heatshield and takeing the arm off the butterfly itself and then just giving it a push?

 

Thanks :)

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I had somewhat the same problem. TTC both turbos fine but when I would go back to sequential the 2 second turbo would not come on. I spent a whole year trying to fix the the problem without any success and I did all the tests etc.etc. I then found the problem and it was the steel vacuum pipes running on the top of the engine. I had changed the pipes from black to polished ones. When polishing a lot of muck was left in the pipes and it got stuck inside. As soon as I changed the pipes everything is fine to this day.

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