Jump to content
The mkiv Supra Owners Club

bpu boost problems


girth45

Recommended Posts

Hi all , my car is a tt vvti facelift tiptronic auto, full bpu earlier this year.

On route back from jae car would not boost above 1.0 bar this is the second time it's happened, so its intermittent, I have searched on the forum and although I have found some excellent info I am still trying to diagnose issue.

So far I have ordered new turbo link pipes as these had started to collapse internally (dont think this is the problem) I have checked both turbo impellers ( both in fantastic condition) no signs of oil in the pipes, or smoking under load.

Checked all vac hoses they are all connected and look fine ( will replace these anyway.

Can anyone help further I believe it may be electrical so maybe 1 of the 4 valves (if someone could point me to the most likely)

Would appreciate any advise ; maybe chris, lee or paul could give me there thoughts.

 

Gary

Link to comment
Share on other sites

  • Replies 70
  • Created
  • Last Reply

Top Posters In This Topic

Given the age of these cars I would replace ALL the sequential control hoses using proper "rubber" hose, not that disgusting silicone stuff, and replace all the solenoid controlled switching valves. Check the one way valve in the pressure tank, too. The VSV's are expensive, but compared to the RX-7 i have just done, there are very few of them. The actual EG diverter needs checking for security of the arm to shaft weld, and that the diaphragm is actually actuating the arm. A Mityvac is a very useful tool to buy.

Link to comment
Share on other sites

Hi chris and thanks for help, can you supply the necessary valves and hoses and at what price? The pressure is that under the inlet manifold? And does it need removing to access it? An where abouts is the eg diverter so that I can check this? Is there one particular valve that could be the problem ?

Link to comment
Share on other sites

the VSV units arnt that badly priced, i think its around 380 for all of them give or take.

 

You can see the diverter under the turbos, there is a valve actuator there on the exhaust, follow the hose back to where it's VSV is, under the first turbo afaik.

Link to comment
Share on other sites

Update.

Having replaced turbo link pipes, vac hoses, checked act operation, and tried another vcv valve, car still not boosting properly.

This morning I let car warn up before leaving for work initially boost was fine 1.0 bar in boost mode 1, 1.2 bar in boost mode 2.

Halfway to work boost dropped to 0.8 in mode 1, and 1.0 in mode 2.

Also saw 0.9 and 1.1 ! Any ideas people, was wondering if it could be air tank? Any ideas , help or thoughts appreciated.

Link to comment
Share on other sites

I was having the same thoughts mark, its only 8 months old but could still be faulty.

 

Worth investigating tho not sure how you'd check without replacing it. Let me know if you need a hand, I'm always up for tinkering with cars.

 

Oh and I've got those HEL hose clips in my car for you.

Link to comment
Share on other sites

He is fitting a greddy blue I bought of here to give better torque and smooth out the overfuelng at high boost. I wont be going single but I am looking at hybrid twins ! It was good to meet you at jae shane. Lyndon coming late afternoon.

 

Ah ok. I went for the DET3 he does for the same reasons/targets plus it does so much for so little money, comparatively speaking.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.