Jump to content
The mkiv Supra Owners Club

Boost problem 0.75bar


Robzki

Recommended Posts

I may have found the problem, I was looking at how the boost controller was plumbed in and thought I would check all the pipes.

 

Am I right in saying that the boost controller solenoid is basically spliced in between the no1 turbo housing and the actuator?

 

If so then in one of those pipes is an inline filter that is blocked absolutely solid, no vacuum or pressure will ever get through. I bought the bc secondhand and as far as I am concerned would heve been blocked from the time I fitted it. I seem to remember thinking that I need to get one before using it. I didn't however think what may happen using the car with basically no connection between the turbo housing and the actuator because the vsv is made redundant. Hopefully you know what I mean.

 

What would happen??

vsv capped.jpg

Link to comment
Share on other sites

I take it this is the actuator for the wastegate btw? I have read as much as my brain will take on the vsvs actuators and wastegates and am none the wiser.

 

Effectively I have taken out the wastegate vsv and then blocked the pipe from the turbo housing outlet and the wastegate actuator :(

Link to comment
Share on other sites

I have looked into it and if the pipe between the turbo housing and the actuator was blocked solid then it would overboost?

 

I'm thinking that possibly the filter is working like a one way valve? it builds pressure against the actuator opening the wastegate, the pressure then can't return and basically holds the wastegate open? Is this possible and if so what would the effect be?

 

I'm thinking that this may be why the profec can't be programmed as it does the p1 part where it just monitors the boost and learns how it works, it gets this info from the pipe on the manifold It then goes to p2 learning mode where it then opens and closes the solenoid to set the boost curve. If the filter was causing such an obstruction then it obviously can't control anything.

Link to comment
Share on other sites

I may have found the problem, I was looking at how the boost controller was plumbed in and thought I would check all the pipes.

 

Am I right in saying that the boost controller solenoid is basically spliced in between the no1 turbo housing and the actuator?

 

If so then in one of those pipes is an inline filter that is blocked absolutely solid, no vacuum or pressure will ever get through. I bought the bc secondhand and as far as I am concerned would heve been blocked from the time I fitted it. I seem to remember thinking that I need to get one before using it. I didn't however think what may happen using the car with basically no connection between the turbo housing and the actuator because the vsv is made redundant. Hopefully you know what I mean.

 

What would happen??

 

im not sure what set up you have but that vsv you have pictured is still conected on my avcr set up the first conection from the left is still attached to the vac system, maybe double check on google how your is plumbed in mate

Link to comment
Share on other sites

All sorted :)

 

Took the filter out and replaced with a straight connection, Tested on 3 runs and got pretty consistent results 1.01 1.03 and 1.02bar I now know what bpu is :) really chuffed and thanks for all the help, really appreciate the advice, it got me looking in the right place. I didn't hit boost cut I assume because the road was so short I couldn't keep it there for 3secs+

 

I'm fairly sure that your vac pipe you still have attached is doing nothing, in fact if the vsv is plugged in and actuated you would be getting a vac/boost leak, mine is capped off on the vac line higher up which makes sense. unless the other side of the vsv on yours that used to connect to the wastegate actuator is also blocked in which case yours and mine are effectively the same.

 

Really happy now, Ive been putting bits and pieces on the car for a year and it has appeared to get slower each time. Just this filter has unlocked them all at once :) completely changed the car. I have a feeling that the filter was very bad to start with and has progressively gotten worse.

 

Thanks again :)

 

Rob

Link to comment
Share on other sites

  • 5 months later...

Ok, bit of a resurrection here, I seem to be having the same problem as this, car is boosting 0.77bar throughout the rev range after installing my HKS EVC 6.

 

I have the VSV capped as per the pic shown in post #27... Is that correct? Is the left most connection still required?

 

My unit was 2nd hand, the filter was very blocked so I replaced it with a new one. One of the vac hoses I used was new, the other was old so I need to check if it is not blocked or cracked again...

 

Any help is welcome.

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.