Loud whining sound on acceleration

Posts specific to the 2.5 litre turbo engine

Re: Loud whining sound on acceleration

Postby bigBADbenny » Thu Aug 01, 2019 1:21 pm

Here’s my incrementally updated avcs diagnosis guide: logging is the key.

Avcs checks.

Log avcs vvt left and right angles with Btssm or Romraider at 1700-2000rpm in neutral and in gear on the freeway, look for vvt angle oscillation, lag or inactivity.

My theory is that slight differences in the left and right avcs oil feed pressures, combined with the self calibrating nature of the avcs system cause one side, usually the LHS, to become overdriven and eventually fail.

The beginnings of this failure is seen as left to right angle lag.

The intermediate stage is one side wildly oscillating whilst the other side operates correctly.

The terminal stage is one side becomes inactive at which point the avcs system deactivates completely.

All stages can be encountered without triggering a cel.

My solution is to start with two new avcs solenoids and then to periodically swap them side to side (eg at 50k mi) or when significant angle lag becomes noticeable in logging.

If either issue is revealed, swap avcs oil control solenoid side to side to see if the issue follows the affected solenoid.
If so, replace both ocv solenoids.

If the issue doesn’t follow, check the ocv oil supply banjo bolts for blocked screens. The filters can be very deep in the banjo bolt hole and or broken up. Use a sharp toothpick to fish them out.

Very rarely, an avcs cam gear may be jammed with debris, or via incorrect installation, usually in this instance it will be locked at a particular angle as revealed by logging.

Go for the easiest tests (logging) first, if all results are negative, eg you have avcs inactivity which does NOT follow the OCV side to side swap, pull the crank and cam sensors to check for contamination by metal particles on the sensor face or check for oil supply issues at the banjo bolt filters.

For dual avcs prefl 2.0t, check if the exhaust avcs solenoids are leaking, the loom can suck oil all the way back to the ecu plug, causing multiple issues.

Log per cylinder misfires.
If misfiring, check spark plug condition and swap around coil pack on the affected cylinder to check if the fault is cylinder or coil pack related, or coil pack loom plug related (usually broken plug clip).

Get an LV (learning view) whilst you’re at it.
LV will reveal inlet leaks, IAM (low IAM = failsafe mode).
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Re: Loud whining sound on acceleration

Postby Ferdimage » Sun Aug 04, 2019 7:47 pm

Finally found the issue....the turbo was so done, I'm just glad it didn't completely go and cause me more issues.
https://youtu.be/VfjRU2FRQ7o
Replacement VF46 is so quite and spools like it should.

BBB thanks for all your help, 1 man tech support on this site haha. Learnt alot from you! so I really appreciate it.
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Re: Loud whining sound on acceleration

Postby bigBADbenny » Sun Aug 04, 2019 7:51 pm

Terrific! I guess the super low oil was the cause...?

Blocked pcv not helping maybe?

Iirc you want to pull the fuel pump fuse, intermittently cranking the engine so as to not burn out the starter, in order to prime the turbo oil supply, prior to firing it up properly.
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Re: Loud whining sound on acceleration

Postby Ferdimage » Sun Aug 04, 2019 8:36 pm

bigBADbenny wrote:Terrific! I guess the super low oil was the cause...?
Blocked pcv not helping maybe?
Iirc you want to pull the fuel pump fuse, intermittently cranking the engine so as to not burn out the starter, in order to prime the turbo oil supply, prior to firing it up properly.


-That looks like the case with the previous owner, at least I was able to remove the banjo filter under the inlet while the turbo was out for safe measures.
-PCV didnt appear too blocked, all the white/blue smoke was from the turbo and busted seals
-Yup did all these and bled the radiator also after the install, drove it back home and its spooling like a normal turbo now.

Super happy :)
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Re: Loud whining sound on acceleration

Postby bigBADbenny » Mon Aug 05, 2019 7:31 am

So good!
So when you installing the silicone inlet, the turbo was ok and failed afterwards?

Just trying to break down the chain of events for future advice sessions :)
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Re: Loud whining sound on acceleration

Postby Ferdimage » Mon Aug 05, 2019 2:00 pm

This is what I think went down.

-Previous owner last serviced the car 6/18 and I bought the car 07/19!!
(Turbo howling was there already but thought its just a simple boost leak)

-Drove the car for a few days then CEL P0011 & P0022 came up - cleared the codes
-Changed oil straight away and pulled out 1 litre from the sump!! (CEL did not come up ever again because the OCV's were getting oil again)
-Got a stock tune from Kido Matt the howling noise got louder
-Installed a DP (Inspected the rear of the turbo for shaft play and it didn't feel that bad at that time) the howling noise was even more noticeable after the install
-Retune from Matt to suit DP
-Installed all silicone intake & TB hose and replacement stock TMIC trying to eliminate all possible boost leaks
(Inspected the front of the turbo for shaft play and it had a tiny bit more play)
But looking at the photo again I knew the fins and gaps didnt look right https://imgur.com/a/DU4t7UQ

-Turbo howling got worse in time and more oil smoke from the exhaust.

The turbo was already dying and all the extra mods and tunes just stressed even more.
I'm just glad it was the turbo only and not the engine.
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