Ok just had a phone call.

AFM fitted. It has a reading but noise and problem is still there.

Front end is being stripped off now to check for hidden boost pipe damage or inter cooler damage.

If all that's ok then I don't know. Anyone any other ideas? I'm two steps away from burning it.

Maybe leak on exhaust manifold or egr feed pipe.

Neither of those would affect power though.

 

Until the boost and vac pipes are all checked it's hard to guess what might be wrong.

Could it be the turbo?

:-S

Honestly at this point it is looking like it but i dont think you can always tell till it is taken off.

The last time mine whistled it was a damaged blade on the manifold side of turbo, but both times I have had turbo trouble it hasnt gone into limp mode.

Did vag com not kick up any errors?

Only errors it showed was the AFM zero reading.

Turbo is off car and doesn't show any signs of issue. It's all free blades in tact vnt moves up and down fine.

Small play in the shaft but not major and surely nothing to worry about as it was blue smoking.

Also front end stripped down and all checked and that is ok too.

This is turning into a bit of a nightmare.

I don't think there was any need to take the turbo off. The shaft and actuator could have been accessed while it was still on the car to check if the vnt mech was free.

 

Did you do the vac test on the actuator and also to test the N75 valve?

Also, did the VCDS operator test the map duty cycle to see if the actuator was set up properly?

N75 normally registers a fault though.

With the maf fault cleared it should be out of limp mode.

Daft question but have all the O rings been checked on the boost piping because they wear aswell.

No the N75 won't always register a fault and can be the cause of numerous headaches because of a split diaphragm or vac pipe.  I've seen N75 valves cause loads of problems and until a vac test was done it would never have been spotted.

 

The MAF is nothing to do with limp mode.  The MAF showing 0mg/s is just a measuring block in the engine.  That's easily checked.

 

This car is NOT IN LIMP MODE.  Limp mode is an ECU activated state and in turn ALWAYS shows an error.  From the hundreds of cars I've ever scanned I've never seen a car that's been in limp mode and hasn't left an error.  Most of the time it's a negative deviation (anything from a boost leak, vac leak, bent valve, cracked head etc) or positive deviation (overboost, caused by anything from VNT sticking to egr jamming).

 

At any point has anyone checked the vac pipes throughout any of this?

 

2 things to check.  Please do this before taking anything else off the car or replacing anything else. These are basic enough tests.

Check all the vac pipes thoroughly.

Unbolt the downpipe and take the car for a drive. (because a blocked cat can cause issues where a car can't rev fully, or can't get up to speed).

Edited 24 January, 201412 yr by Bazmcc

Car has complete custom pipe work as it's running a universal front mount so won't be o rings.

Car has an uprated map sensor. So would the n75 be absolete?

Egr is deleted. So won't be that.

The car did die overnight worked perfectly the night before.

The N75 is the vac valve that controls how open or closed the VNT mechanism in the turbo is so if it's obsolete you either have an extremely modified engine bay or an extremely messed up one.

 

Which map sensor is in it?  The OEM 051 C 3 bar map sensor should have been fine.  However, has that map sensor been checked on vcds to see if the duty cycle is operating the turbo correctly?  or at all.

 

As for the custom pipes.  They can leak like anything else.  Have you visually checked the pipes and manually checked that the fittings are all on and tight?

If it gots egr delete then two of vac lines would need blocking, if something has happened to those would it affect the other lines.

Right it's all

Back together and still the same.

However by accident we did think it was fixed until we realised the actuator pipe was off.

It didn't drive any better but the whine noise disapeered. Could it be the actuator??

Also can one be bought off the shelf?

I will probably be corrected but its the actuator that controls the vnt.

This could cause the noise as the vane will be at the wrong angle of openess (bad english but cant think of the correct wording.

If you pressure tested the vacuum pipes and they were fine then it could be I have seen the fault mentioned a few times on here.

I found this http://www.briskoda.net/forums/topic/174110-turbo-actuator/ if you have access to vag com you could see if this works.

I think actuator is part of the vnt bit and must be able to change it as there is an electronic conversion.

The actuator is just a vac diaphragm with a rod on it that controls 1 vane in the ring of vanes and moves the vnt plate opening or closing the turbo.  They can be bought new yes.  They can also be tested by using a vac tester on them.

 

That test richard is talking about is the N75 cycle.  It operates the vac to the actuator.

Looks like turbo is gone. Not sure how or even what's worn with it but that's all it can be.

Get it to a specialist, some will have a look at it for free and confirm before you go splashing out on a new one.

If its the garrett one they can easily be repaired at a fraction of the cost of a new one.

Know anyone who can repair it though? My mechanic says it's not worth using a rebuild kit and DIY as it won't be balanced properly and won't last long.

I took mine to aet turbos, maybe a bit far for you to travel but you can post it.

They took mine apart found the problem and phoned me at every stage to explain things to me.

They will only replace what needs replacing aswell.

what did they charge you for that?

I will try and find the bill out its safe somewhere.

Full cost was around £350, but that was to have it hybrid instead of standard repair.

When I looked it worked out cheaper than a second hand turbo.

Best off giving them a phone call pal.

ive got a new unit for £380 of a trader on here. hybrid with pd 170 internals

Not sure what pd170 was, you might need a remap after because it might run a bit different.

Faboka would be one to contact.