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The mkiv Supra Owners Club

no boost from 2nd turbo


ashaero

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I do feel your pain, frustrating isn't it.

 

If you have eliminated the VSVs and you know the turbos are capable of boosting by running it in TTC mode then you need to move on to the small hoses in the control system hoses. In my case and I think also a lot of other peoples, it was the hardest to get to hoses, two short lengths on each side of the engine that join to the hard pipes that run across the bulk head. As Chris said, most people wouldn't even know they are there and they are a bit of a nightmare to change with most of the operation done by feel.

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Well, got my new egcv vsv today from Japan. Fitted it and changed the pipe work back to sequential. Took it out for a spin and the original problem is still there :-(

Works perfectly in TTC mode so I guess that means there is no problem with the boost pipes.

Any further suggestions?

 

 

Have you removed, examined and either renewed or replaced to four soft hoses to the pressure reserve tank??????? If not you should do this as the next port of call. Just buying stuff willy nilly is madness, the whole sequential system is easy to diagnose piecemeal, it just takes time and patience. You can even diagnose if the ecu is signalling the VSV's correctly with cheap, simple tools.

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Hi Shane and Chris

 

I had sort of discounted the hoses as some of the time it works fine. I would have thought (and correct me if I am wrong) that a split or disconnected hose would cause a constant problem. I haven't changed the Iacv vsv yet because I believe that if that one was the problem I would retain the boost pressure from the 1st turbo, where as mine boosts (0.6 bar) up to 4000 rpm and then drops to 0.1.

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just read some more about the seq system. it's quite "easy" to diagnose and fix this problem

 

http://my.prostreetonline.com/2014/10/16/how-to-troubleshoot-2jzgte-sequential-turbos/

 

Have had the same pain in the ass feeling you have now, but hang in there.. suddenly it all makes sence! kinda like a Matrix moment with angels singing and all that;-)

 

just start taking of vacuum hoses one by one and check and re fit. from the Y pipe down to the pressure tank and back upp to the vsv and actuator. this is the only route you need to consentrate on!! check that the actuators opens at correct pressure and stays open then closes at a normal rate. (Could be sticky actuator or vsv that is at fault) dosent have to be all the way broken to mess it up for you..

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I will start removing pipes and wait for the singing angels lol.

 

would the actuators operate whilst revving the engine in neutral?

 

No, you need pressure..

if you have a mittyvac or other vacuum tool.. or try sucking/blowing thru the vacuum hose to the actuator. Pry them open and put you're thumb over the hose to see if it holds vacuum.. you wont know the pressure value, but you will know if it opens closes and holds pressure:)

 

 

 

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No, you need pressure..

if you have a mittyvac or other vacuum tool.. or try sucking/blowing thru the vacuum hose to the actuator. Pry them open and put you're thumb over the hose to see if it holds vacuum.. you wont know the pressure value, but you will know if it opens closes and holds pressure:)

 

 

/QUOTE]

 

But since they work fine in ttc, I would start with the hoses. Also make sure they are on the right way! If they are reversed system wont work:) check the vsv with a voltmeter to ensure they are OK according to repair manual. also have a look at the connectors.

 

 

 

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