Turbo Noise Change On Low Boost Help.

[FPVF6355]

A couple of months ago, I gave the car a quick stab on the pedal when it was cold (Stupid I know)

Anyway , the boosting sound changed from the normal whistle to a louder Woosh sound, and stayed that way.

So far I have taken off every hose and couldn't find anything wrong or obvious leaks.

Pulled out the complete turbo, and found just about every bolt was loose, and also found the gasket from manifold to compressor housing was not even there ?? weird??

I put the turbo back in (couldn't get the missing gasket on a sunday, so just did it up tight for now) plugged up the intake pipe and pressure side pipe, connected the air compressor and cranked it up to 16PSI and I can just hear a very small leak somewhere around the turbo housing. But it all holds pressure for a few minutes, so it's a very slight leak at the joint where the gasket is missing.

But that gasket was always missing, so it doesn't explain the Woosh sound that appeared suddenly.

The spool feels OK and if the turbo sounds fine spinning without boost (hose disconnected)

And I also checked and cleaned the filters, no blockages.

When I first drove it, after putting turbo back in, the woosh was gone, then it cam back on second test (5 minutes later)

Could it be the waste gate valve is not seating properly ?

Also I am getting a "System too rich" fault code

I'm getting really sick of this noise

Any idease would be good.

[arronm]

There is no gasket to the exhaust manifold.

[FPVF6355]

There is no gasket to the exhaust manifold.

You mean there's not meant to be a gasket from the housing to the exhaust manifold ? Why ?

so as far as I can tell there's no leaks, the spool looks in perfect nick, and it has very little play,

It's done near 150,000kms could it be that turbo is just worn ? and it's just in need of a rebuild ?

The only other thing, is when I had a new CAT fitted, I could hear a slight exhaust leak at low boost, that noise has gone and been replaced by this load woosh sound at low boost.

If you get a descent exhaust leak near the dump pipe end, will the spooling sound get louder ?

[Zerosignal]

He means from the factory there is no gasket there but by all means throw one on itll help keep it toight like a tiger. You probably have a small crack in the housing causing your small leak, but I doubt its related to your sound, have you cleaned the boost solenoid? Also is your oil feed line stock or have you installed a braided line, I once let a service dwindle too long and my turbo changed sound and was a little laggy till I dropped new oil in.

[Gasman]

There is no gasket to the exhaust manifold.

Some tuners that I have spoken with recommend removing the gasket to stop the nuts loosening off. I lost the nuts twice in a space of 6 months. The gasket is now been out for a month or so ,so only time will tell.

[1600dave]

From the factory, they don't have one & the turbo comes loose constantly. Ford specify not fitting one in the workshop manual too.

However the sonic/mtq gasket kit for the xr6t does come with one, I'll be fitting it with stage 8 fasteners.

[FPVF6355]

He means from the factory there is no gasket there but by all means throw one on itll help keep it toight like a tiger. You probably have a small crack in the housing causing your small leak, but I doubt its related to your sound, have you cleaned the boost solenoid? Also is your oil feed line stock or have you installed a braided line, I once let a service dwindle too long and my turbo changed sound and was a little laggy till I dropped new oil in.

I've cleaned the factory oil line filter under the sensor, and changed the oil, after Fraud put some rubbish in it that went black in 2000 k's

I sprayed some WD into the wastegate solenoid.

I've tried and looked at everything, I think the only next step, is try to source the sound on a dyno.

Best way to descibe it is it's a deep whistle sound and you can hear it very easily both in and out of the car, definately in the turbo area.

I'm going to kick myself if I find it's something really obvious.

On the upside, I have done more maintenance than fraud would ever do, I can't beleive the amount of loose bolts I found, and Fraud never picked it up in 2 services in 8 months, Which basicly amounts to $1000 to have rubbish oil installed.

If it ends up being a sick turbo, I might think about going over 300rwkw with a new fresh one, bigger cooler and better piping etc.. it's just on 290 as is with 16PSI. with stock cooler and piping.

I had a trutrak fitted and it's brilliant. so might as well use up the extra strength in the diff.

[FPVF6355]

Found it !!!!!!!!!!!!!!!!!

Wastegate solenoid not working, allways stuck in open position.

$50 part

YEAAAHHH

[Barra]

how did you test this to find the fault, was it done while still on car also?

[FPVF6355]

^{how did you test this to find the fault, was it done while still on car also?}

^{It was the last thing on my list to pull off and check thoroughly.}

^{According to the Haines manual, with power off the solenoid it should be closed, anyway, power off} I ^{blew through it., power on} I ^{could still blow through it.}

^{Got the new part, and} I ^{could still blow through it with power off. Which according to the manual is wrong ?????????????}

^{Anyway fitted the new one and my "system too rich" fault code didn't come back. and it felt better.}

^{The whistle noise seems to have gone, but} I^{'m still going to get it dynoed ,} I ^{still think it's dropped some boost, but that could be just me getting use to the power.}

^{To check it,} I ^{just unbolted it and blew through it, with it still plugged into the harness.}

I ^{saw a video of a car running 400rwkw and that looks SWEEEEEET, gime more power !!!!!!!!!}