sticky exhaust valve???

[Guest]

hello everybody im new here and i got a problem funny enough.

this is what happens

96 GTB

when boosting if i pass through into secondary and then drop back onto primary i have little or no boost and engine note is different then engine note will come back and i have full boost again. its not VOD i know all about this i beleive it is the secondary exhaust bypass valve sticking open. has anyone come across this problem before?

i am going to clean my solenoid out tomorrow and see if that helps. ???

[Hailz]

Mine does the same thing, has your's always done it or has it gotten worse?

[Guest]

it just started doing it one day its been like it for about 6 months now. i,ve swaped the engine block and put another primary turbo on. (cooked both) still the same so im thinking its the exhaust valve. or the solenoids. will clean solenoids and see if that helps. will keep posted if i can solve the problem.

[Guest]

ok cleaned out solenoids with carb cleaner and did not fix the problem.

a couple of them are not working properly so will replace when i can get some $$$

i found another actuator for exhaust valve i will replace it and see if that works.

[Guest]

How did you get on? I think you share the same problem as both our Subarus '00 BH and '95 BG. Check out my description here - http://www.clubsub.org.nz/forum/index.php/topic,7573.0.html

I am most probably for good measure going to do the AFM clean up/resoldier thing on the weekend too. See if that has any effect.

[Guest]

that sound like what i get alright. i swapped the solenoid box and its still doing it. so i think it might be exhaust actuator or the one on the intercooler pipe. these are the only 2 things i have not tried yet. i have a spare exhaust actuator i will try that after i do my clutch slave cylinder as this has now started playing up.

[Guest boostin]

Make sure the exhaust control valve has no play between the valve itself and the actuator arm. That causes all sorts of issues.

[Hailz]

Now where exactly would I find the exhaust control valve? Is it the one behind the 2nd turbo?

[Guest boostin]

Between the up-pipe and secondary turbo.

[Guest]

Anyone have a pic of that up pipe that is relevant? (preferably one with a dummies arrow on it )

Might be on to something here, as only did it once or twice this morning on my BG. Common denominator... I only used the secondry turbo once or twice (then the problem occurred). Still to service my AFM though.

[KarlGTB]

Both my dads 94 GT and my 96 GTB do this. I might be wrong but I think what you are describing is a normal characteristic of the mighty twin turbo. If you change gear at too lower rpm on secondary and end up somewhere in the range of 3-4000rpm with full throttle it will happen every time. You'll eventually get boost or it'll change back to just primary but it can take a couple of seconds to make its mind up. The different engine note is just because its still in secondary mode, only at a lower rpm so it seems strange. Happens exactly the same in both cars, I'd be stoked if theres a fix but i always thought it was just another face of VOD.

It probably wont help you, but you can get it to cycle all the twin turbo system actuators with the diagnostic plugs under the dash (both the black and the green i think), you should be able to hear the difference in engine note between primary and both.

[Guest]

That must have been what I heard all switching and sucking and puffing when I was clearing my ECU codes the other day. Must still have vacuum in the tank and doing a self check or something, because the black box of death was working over time with ignition on, engine off and green and black diagnostic plugs connected. Had me concerned at first

[Guest boostin]

The greens connected and black disconnected is D check mode. It force runs all relays and solenoids. Good for checking them when a circuit has a fault. It does drain the battery pretty fast though.

[Guest]

i dont believe this is a common problem with the TT, as i have had my GTB for 5 years and it was not like that when i got it. i will try swap the exhaust valve actuator this weekend see if that helps. if anyone has a TT that doesn,t do this let us know.

might try taking one in a car yard for test drive see if i can find one that doesnt do it.

[gtlegacy]

mine does this to especially if u rev just past the switch over point it changes to the 2nd stage and it bogs down if you dont have any momentum

[funkytown]

 gtlegacy said:

mine does this to especially if u rev just past the switch over point it changes to the 2nd stage and it bogs down if you dont have any momentum

my old BG was the same as well

[gtlegacy]

sounds like another thing to do with the Twin turbo system where the computer cnt decide if you are going to boost it hard or just changing gear to tootle around