My turbo dont boost

[gemiz]

Hi all.

My 7m-gte stock CT26 turbo dont get any boost.
When i pulles of the boost gauge goes fra -2bar and stops at 0, and just start "screeming" like the wastegate is open. I have checked the turbo and it looks okey, it is spinning fine, and does not touch the tubinehousing.
And i have checked for any leakage with in the pipeing and IC with there isnt.

Is there a possibility that my wastegate just opens and lets all the exhaust out there?

Regards G

 

[NewWestSupras]

Check the bov. blow through it. If you can, it's pooched. Make sure the piping isn't leaking again, anywhere...that's a start, gl.

 

[gemiz]

Hi.
Thx for quick reply.
The bov is tight, no leaking there either.
I have replaced the IC and all the pipeing. Also replaced silikon hoses and clamps, so there is no leaking there either.

 

[Fletch124]

The factory boost gauge is no good. Get yourself an aftermarket boost gauge. I recommend Prosport, or if your feeling wealthy get a Defi.

 

[gemiz]

i have a aftermarket boostgauge.
But the problem is not the gauge, i feel it when i am driveing.. It like ann NA supra with open wastegate scream.

 

[fixitman04]

stupid ? have you checked the wastegate and the actuator?

stuck open or weak actuator

either that or a leak

 

[gemiz]

I will check the wastegate more closely tomorrow.

Is there anyway i can check the wastegate and the actuator is working properly?

btw. Could it happe that the wastegate or the actuator would be defect this way?

 

[rayall01]

Screaming sounds like a boost leak to me, like a clamp might not be tight enough. Or a crack in the hose or piping, not likely as you have just replaced those.

 

[Angry7M]

Check your codes brotha, if you have a major boost leak like that you will mostly likely get a code 34/

http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?Section=FI&P=23

 

[gemiz]

Yes.
Thats why i bought a new IC, pipeing and clamps.

I will check the wastegate again, and go over all the pipes and clamps. Hopefully ill get to the end of it... Kinda stinks driving a NA again.

Thanx for all reply so long.

 

[7mMoneyPit]

Might want to double check your stock bpv mine did that once and I spent a week looking for vacuum leaks but turned out the bpv would leak under boost and vent it back into the intake causing a no boost situation, if it was a vacuum leak smaller than that you would still build boost maybe not as much but you'd probably run richer and possibly hit fuel cut off really low.

 

[gemiz]

I dont have stock valve, it an bov aftermarket. I have tested this and is very certain that it is working.

But hopfully i will be back in my garage tomorrow and check all of this out one more time.
If i am not able to figure it out i think it time for a t61 ct26 upgrade Time will show.

 

[Angry7M]

I dont have stock valve, it an bov aftermarket. I have tested this and is very certain that it is working.

But hopfully i will be back in my garage tomorrow and check all of this out one more time.
If i am not able to figure it out i think it time for a t61 ct26 upgrade Time will show.

Bigger is not always better

 

[dumbo]

I think you'd be hitting fuel cut if it was a major leak. Check your wastegate/actuator, broken spring maybe?

A good stupid quick way to check, only if you have good self restraint:naughty:

Pull the signal hose(vac line) off the WG actuator, plug it, and go for a quick drive. I think you'll know really quick, just make sure you let off if boost starts building

 

[gemiz]

This can work if the wastegates default position is closed.
Can anyone comfirm that?

 

[dumbo]

This can work if the wastegates default position is closed.
Can anyone comfirm that?

Do you know how the wastegate works?

Let me dumb it down. It is normally closed. Manifold pressure works on a diaphram that ultimately connects to the WG. When manifold pressure reaches a specified pressure(Stock 7m-gte, approx 5-6psi) it over comes spring pressure and opens the WG so exhuast gasses bypass the turbine so boost no longer climbs but remains steady.

Trust me its a quick check to narrow out the WG as the problem.

I'm not resposible for engine damage! LET OFF THE GAS IF BOOST STARTS BUILDING!!! Although you should hit FC.

 

[gemiz]

Hi.
Just want to bring my post to live again.
The issue remains, as the car has been stationary for the past 6-7months.

Ill try to post all that have been done and tested with results.

1. New IC. OK
2. New Pipes, clamps, and silicons hoses. OK
3. Tested pressure with compressed air in the intake. OK, it was tight, so there cant be any leaks from the intake on the turbo to the Closed throttle valve.
4. Turbo Checks out to be fine, also the actuator and wastgate is Good. Opens at stock PSI 0.5-0.6.

Im am then wondering is there might be a leak behind the throttle valve. Between the Valve and the engine (intake manifold). But i reckon it should be a large leak, Cause i have 0 boost. It never
goes above 0 PSI/BAR.

Also, i havnt been looking at any electrical yet. I dont belive this problem can be caused from an electrical issue. The turbo should be pretty much mechanical in my opinion.
But if anyone have any opinions regarding that. Please tell me so.

I will also go check me BOV valve as someone pointed out earlier. Its just a damn long time since i have spent any time on this car, so i cant remember if this was tested or not.

 

[gemiz]

bump

 

[Mr.Forks]

hey, it seems that I'm having similar issues,
did you ever figure out what was causing yours?

 

[paradox616]

does the car run any worse while full throttle @ 0psi? if you have a bad boost leak i'd expect to see a small smoke cloud from venting measured air.

get a friend to follow you and look if any black smoke is comming out the exhaust, if yes then you have a bad boost leak

If it were me, id be pulling the turbo off and inspecting the compressor housing o-ring, and checking the wastegate flapper movement and shaft play, you'd be suprised what you might find, i found a chunk of my 57trim comp housing missing on the bottom, when i installed it the chunk was still there.


Did you end up checking for codes???? i know a disconnected knock sensor will prevent boosting as well.