[Mk2] [Turbo] No Boost - Can't Diagnose Please Help!

[Craigo]

Hi Guys,

Could really do with some help on this.

About a month ago i got in my car to go to work and after about 2 miles i noticed i wasnt getting above 0psi. There is no smoke coming from the turbo or anywhere else and other than having precisely 0 boost, the car is healthy.

I've checked the error codes - all clear.
The compressor wheel of the turbo has no play and is spinning freely. It is
my understanding that if this was not spinning, although appeared in tact, this would suggest the exhaust turbine wheel was damaged. As such it appears the turbo is good.
Ive checked the dump valve and this is fine.
I have an AEM EBC Tru-Boost controller. I disconnected the solenoid and connected wastegate directly to the compressor housing. still no boost.
Done a compression test and all cyclinders 150psi or thereabouts.
I've reset the ECU.

...still no boost. Any ideas guys as i'm at a loss. Im not a great mechanic but i understand other things to check would be the VSV/actuator rod/..not too sure what i'd be looking for.

..Something to consider..the night before this happened i went to turn on my car and the battery shorted out. disconnected it-reconnected it and all was fine (although i didnt boost on the way home so i have no way of knowing if this was related to the loss of boost). Any other electrical things to check other than ECU/AEM EBC which i seem to have covered?
Thanks for your help in advance.

Craig

[3S Service Centre]

Craig mate it sounds like your exhaust wheel has fallen off quite common.
James

[Craigo]

Hi, if that were the case then would you not expect the compressor wheel not to spin?
Thanks

[Slarty]

Luck of the draw really (well, kinda, if you follow).

If the exhaust wheel falls away from the turbine shaft then the inlet will still continue to turn freely.

You're best off geting the elbow or downpipe off and checking both sides at the same time.

[JJ]

Easy check... pull the induction pipe off for the turbo where you've checked the compressor rotation... start the engine up and see if it rotates... If it doesn't... theres your problem !!

9 times out of 10.. the ceramic turbines sheared... What normally happens is axial and radial play occurs and the turbine catches the turbine housing, causing it to snap off the shaft !!

These ceramic turbos are great in principal as they yield many advantages, however, any sort of wear and they're short lived !

[jimGTS]

i know its random suggestion

but what about a lower ic pipe popped off, or clamp broken, so leaking all the boost?

could be way off tho

[Craigo]

Thanks for your comments.

Jim- you mention a lower IC pipe, i thought there was only 1 inlet and 1 outlet which sit on top of the IC? I'll have a look later but difficult to view the bottom!

JJ - i have started the engine and viewed the compressor wheel and it is spinning as normal. Obviously this only shows the compressor turbine but my understanding is that the compressor turbine would not spin if the exhaust turbine had fallen off or sheared as there would be no built up pressure?

Cheers.

[jimGTS]

never mind, i thought you may have an uprated IC (in which theres an upper and lower pipe)

if stock ic and piping, safe to say youd know if a pipe had split or popped off.

[Slarty]

I wonder if the CAT has collapsed and is blocking the bottom of the downpipe...

Is the car holding back or revving freely through the rev range but just without any boost?

[Craigo]

Car is has decat.

Not hesitant no but then im not going above 2,000rpm without the turbo working properly

[SFLee]

if you broke the exhaust fins it may still spin just not enough to make boost

or bov jam open

can you hear air leak

[Craigo]

when it gets to 0psi (from negative) it sticks and you can hear a noise which i can only describe as a faint noise similar to your neighbour using the vacuum cleaner.

[gaztubby]

That sounds familiar I was making 2psi of boost max and there was a wooo noise. Turned out to be the turbine blades broken off but there was still enough left to turn the compressor but not enough to make more than 2psi of boost. Only way to check is to get the downpipe off and have a look.

[Driftlimits Performance]

sounds like a pigeon?

Dead turbo!

[Craigo]

Thanks. Will have a look next week and report back!!

[JJ]

Agreed ! Somethings gone through, spark plug ceramic / water injection nozzles too large etc usually takes a fin out !

Either way, you'll find damage to the turbine !

[mr2magic]

Another thought: Wastegate stuck open..I know a few of the berk style downpipes had this problem and needed to be ground out so the wastegate flapper could move freely. Have a look at the actuator and see if its opened.

[Craigo]

Hello again,

Got the downpipe off today and had a look at the turbine wheel - 4 blades had snapped off!! think that solves the diagnostic problem.

One question - whats the best way to get the turbo off the car? finding it tough trying to do it at the manifold - is it best to get the manifold off and then disconnect the turbo from it once its off the car and more accessible?

Thanks
Craig

[Craigo]

anybody help? thanks.

[Birdygts]

I take the turbo and manifold off complete with the oil feed and return pipe still conected . I can remove the turbo that way in about 40 mins, hope that helps