7mgte + bleed valve + boost gauge = 5psi?

[Kedderz]

Gday, first time poster long time reader. Please bare with me im new with turbo cars so may get some terminology wrong, along with spelling.

Ive recently got myself a mz20 soarer with a rebuilt 7mgte, mhg + arp bolts, which amongst other things has a bleed valve. With no boost gauge ive been babying it off boost since ive got it, and ive set the bleed valve to the lowest possible setting.

Today ive installed a boost gauge, ran the plastice piping and installed the t piece as instructed and took it for a spin and got 5 psi. next i turned the knob twice around 360 degrees, another quick splurt up to 100kmh and again 5psi.
I then again turned the knob 2x360 degrees and another spin to 100, and again 5psi.
At this stage i decided to stop and go to a mates house and test his boost gauge with the same effect, only 5psi.

Question : is the bleed valve faulty?
Question : is the wastegate just ignoring the bleed valve and perhaps is stuck open thus only allowing 5psi?

What should I try to narrow it down a to the faulty part(s)

Thanks in advance, Adrian.

[ViPeR_NiPPleX]

what brand of bleed valve is it? I tried a GFB bleeder on a ma70 and found it took many turns before it started to work. One test could be to unhook your wastegate and see if it boosts any higher, just don't go nuts as it will go into boost cut.

[Kedderz]

brand is unknown to me unfortunately, but there is now a picture in the orginal post.

im letting it cool down now once its cool enuf to safely touch, ill try what uve said

[whatthe?]

I agree with James, my old soarer had a turbosmart bleed valve on it and it did squat until turned at least 5 or 6 full rotations. Id suggest turning it all the way out (all the way anti-clockwise should be full boost) then do it up a few turns and see how that goes

[Kedderz]

ill give that a go this arvo and let u guys know ;-)

[Kedderz]

ok, adjusted the bleed valve as suggested and no affect still only 5 psi
with my under the bonnet antics i also found that this wasng connected.

am i correct in assuming this is the o2 sensor and it should be connected?

[whatthe?]

That is the 02 sensor plug and definitely should be connected. Not sure if that'd explain your boost problems though, it seems your bleed valve might be foobared

[Kedderz]

the only thing im yet to do is disconnect the wastegate, ive got a mate coming around (toml from here) as hes had experience(s) with the 7m.

[Yian]

Just unhook the boost controller Oh.. and boost 'cut' will feel like the engine cut out for a half second, and cut back in. That's if your wastegate works.

[Kedderz]

bit of an update the car is throwning o2 sensor errors and it appears that one of the wires going to the sensor itself has been broken/cut/who knows.

ive spliced in a wire but the errors continue....

by "unhooking" the bleed valve do u men just removing it and plumbing the 2 now useless pipes together (which were conencted to the bleed valve)?



edit also tested the stock bov, works oki dokies.

[Yian]

A wastegate works by sensing the amount boost through the vacuum line. Bleed valve goes into that line to 'lie' to the wastegate about how much boost is present, which lets you run more boost. To unhook the line completely (ie, just let the vacuum hose hang loose) the wastegate just thinks that there is no boost. Ie It will boost as high as your right foot can go.

Unfortunately, once it hits about 11.4psi, AFM will max out and you will hit boost cut. That way, you know the wastegate is working. If it is still only boosting till 5psi with the wastegate line unhooked, the wastegate is stuck open then.

[fixeruperer]

bleed valve is probly in the rong place or rong way around make shaw the bleed valve is t'd inbetween turbo actuator and pressure side of system ( to somewere on ya inlet manifold or i/c piping)
screw it all the way out then set boost buy turning it down if ya want

[Kedderz]

bleed valve has to be the issue as ive now as suggested removed one of the vaccume lines to the wastegate and it allowed me to boost up to boost cut, so i think im up for a new boost controller

now a new problem, whats the easiest way to replace the wiring for the o2 sensor? from what i can see it goes from the turbo/exhaust then feeds along side the head, then to the plastic that covers the timing belt then disappears, i have a temp patch where my wires have broken but id like to replace it, any suggestions?

[Danners]

This may interest you...

http://www.supraforums.com.au/forum/...t=22501&page=4

[Kedderz]

i literally just signed up to those forums and was browsing the forsale section when you posted that ;-)

ive registered interest so we'll see how it goes. Im going to ring repco/sprint/parts stores to see if the bosch replacement is not as $$ as the geniuine toyota one is.