I Can Only Get 5Psi And Nothing More? Wtf

[R34-CoNvIk]

We have a R34 GTT

Mods:

Link G4

Standard Turbo

Waste spark set up

3" exhaust

Intercooler

Its in the shop, and both the mechanic and us are stumpd as...

The compression in the cylinders is all good

Turbo has been tested, there is no air leaks anywhere

even with the turbo wastegate closed off it will still do 5psi

Any clues on what is happening would be awesome

Cheers R34-CoNvIk

[Tommy Kaira RL]

I had a blocked cat that wouldn't let me get boost over 3psi. Its worth taking that out for a look. Mine was running 20psi when I went out and when I came home it was blocked.

[Moodles2]

Is the dump pipe a split design? It's possible the flap is stuck on the dump's divider (stuck half open for example).

I assume you have some sort of manual boost controller or EBC? You might need to run a new vacuum hose straight from the boost controller (manual or EBC) to the wastegate, and/or a different boost source for it.

[mad082]

+1 for a possible blocked cat. a mates 33 i did a turbo upgrade on wouldn't go any higher than 12psi even with the hose to the wastegate removed.

[R34-CoNvIk]

3'' all the way though and still the same.tested the turbo all good the motor has only done 80.000km.HELP HELP its been in the shop 4 six months we stumped

[34GeeTeeTee]

3'' all the way though and still the same.tested the turbo all good the motor has only done 80.000km.HELP HELP its been in the shop 4 six months we stumped

Have you dropped the cat like the guys have suggested? Checked for blockages etc?

[R34-CoNvIk]

yes the cat been cut out.it sounds like it under load when you rev.the blowoff valve goes off early and it set hard its not leaking.timeing been set ova and ova diffrent tunes it must be something .f**k f**k this thing lucky its a skyline.HELP .....SOS...

[Tommy Kaira RL]

How about you explain in detail from the beginning what you have tried and don't reply like a text message its hard to read between the lines.

yes the cat been cut out.it sounds like it under load when you rev. <<What exactly are you trying to say.

Are you just assuming the cat has been cut out because it sounds like it under load when you rev.

You have said there is no leaks then you might have a blockage.

What tests were done to the turbo?

[PM-R33]

Post up a dyno graph with a power and boost plot to make it easier to see what is going on.

[mad082]

Have you tried putting a boost gauge before the intercooler and one after it to see what sort of drop you are getting? May have a rag or something stuck in there

[R34-CoNvIk]

Right, we have closed off the wastegate and still got only 5psi

we have put 3" exhaust all the way through,

we have got 5psi before and after the intercooler,

we have retarded and advanced the timing, as well as setting up different O2 values

we have checked that the turbo wheels arent loose

we have checked the compression on all cylinders

we have checked all the injectors, put a waste spark setup on it

There is a link G4 storm installed

we have tried running 20psi through the link and the engine just wont do it?????

we have bypassed the intercooler, going straight from turbo to manifold

TCS has been disconnected (would it help taking the whole unit off the throttle body?)

Cat has been removed.......

all the new electics have been checked over more than 5 times.....

Runs hotter than usual when its idleing

Have put electric fans on @ constant 92 degrees

When engine is reving up in neutral, its as though its taking off in 1st gear, Sounds like its under load

and has no grunt at all when test driven????????????????

Cam Angle Sensor has been replaced

Just a few more questions....

Could it be that the timing belt has slipped a tooth on one of the cams?

Could the crank angle sensor be playing up?

Have the knock sensors got anything to do with this problem?

To me it sounds like its an internal problem?

Any feedback would help greatly

Cheers R34-CoNvIk

[mad082]

it could be that the timing belt has jumped a tooth. i've seen some pretty weird stuff happen with cam timing that is out. a mate had a CA18 with a broken cam (so timing was variable, LOL). yo ucould get it to blow flames by pumping the accelerator at about 2000rpm. it was also a slug at times. sometimes it would drive fine, other times it felt like you had your foot hard on the brakes (this also resulted in it making full boost by about 1500rpm).

[ricsvtr]

Pretty sure the stock wastegate spring is set to open at 5psi - the stock boost solenoid opens after a certain rpm to raise boost to 7psi.

[ricsvtr]

sorry didnt read your post fully....

[NYTSKY]

92c at idle ib bloody hot.

Did you even check base timing? Does it have aftermarket cam gears?

[gotRICE?]

This may be a silly question, but do you have any sort of boost control? You say you have "run 20psi" through the link, but if there is no boost solenoid to talk to it wont do anything.

One other thing, check that the auxiliary output for the solenoid is actually switched on. Iv done changes before, and forgot to save them, or loaded and stored old tunes that didnt have recent changes etc.

If the solenoid is non existent, or the auxiliary output isnt configured correctly, then you will only be able to run 5psi. As thats what the stock actuator is rated at.

Try this too, hit F12 while in PCLink with the car connected, it will bring up the runtime values. Find the auxiliary output you wired the boost control to and see if its switched on there. Its also possible it has an RPM lockout. Might need to give it a rev to activate too.