Hi everyone

 

Sorry to return to the topic of 1.2 TSi turbos/wastegates, but my problem isn't quite like others (e.g. here and here) and it has recently left me with limited power in difficult situations (busy uphill dual carriageways).

Between 1.5k and 3k revs I get a rapid stuttering (per 5x per second).  It can be controlled by easing off on the accelerator and changing down (usually 2 gears).  If I ignore it, I get a ping and the EPC, ECL and ESP (Electronic Stability Programme) lights come on amber.  All 3 lights always come on together.  There is some loss of power, and I need to stop and turn off the ignition to clear the lights.  There are no stored or pending fault codes on my OBDII reader.

 

Thinking it must be to do with the turbo pressure building up, then the wastegate opening, then closing and building up again in a rapid cycle, I removed the actuator to see if anything was jamming, but the actuator and wastegate seem to move freely.  I removed the shim that was fitted in the recall, and this improves the situation.  I recently tried putting it back, but this made it worse.  I also changed the actuator with a reclaimed unit from a German dealer.  I know that you can't just change them without recalibrating, but I did anyway and it made no difference.  The problem appeared suddenly about 5 years ago and I've lived with it since then.  Previously I had no problems (or turbo lag), both before and after the shim was fitted.

 

I doubt it actually needs a new turbo and figure that it is just a sensor or calibration.  Could an independent turbo specialist do this?  Anyone have experience of Total Turbo Solutions?  Or am I barking up the wrong tree?  Would you try other things first?

 

Any advice gratefully appreciated!  If I get it fixed I will have a spare actuator (I forget which length) available. 

Yes, a good turbo rebuilder will be able to check it. They may want to remove the  turbo though to inspect and bench test. Give a few a call. I don't have any experience of using one but there was a good crowd mentioned on here a year or two back to rebush a 2.0tsi octavia turbo Westgate. Dealers just change the whole turbo...

 

To test your over boost theory at small cost. Get a cheap obd dongle buy torque app or similar. Take a passenger with you to monitor boost in the situation the problem occurs.

 

Also scan for faults. To do it more thoroughly search for a member with vcds and log data when the fault occurs. 

 

 

 

 

Thanks TheClient for your reply.  Here's an update.

 

I called Total Turbo Solutions.  They were only interested in refurbing or swapping out my turbo.  I don't think the turbo itself is at fault, so I don't want to incur the cost or disturb "the plumbing" unnecessarily.  Also they didn't think that any calibration is needed after reintalling, when other sources (including SSP 485) suggest it is necessary to recalibrate the ECU when changing the actuator.  Perhaps something to do with the ECU learning the voltages on from the hall sensor at the end stops?

 

So I then did more internet research.

I read Self Study Programme 485, which extols the virtues of the "electrical charge pressure actuator" and is available here.  

 

As my replacement actuator from eBay (a clone, not made by Mahle) hasn't solved the problem I decided to service and reinstall the original actuator and to put the shim back from the recall.

 

I followed the post of VeeFource on 1 Oct 2019 to service the actuator.  I found my sensor was moving just fine, so I didn't lubricate it, but I did put silicone grease on all the plastic gears and on the shaft where it leaves the body of the assembly.  This made a noticeable difference to how easily the shaft moved.

 

When I reinstalled on the engine I found the wastegate arm itself still moved very freely.

 

I followed the advice in the comments to this YouTube video to calibrate by turning the ignition on and off and then waiting 5 seconds 15 times in a row.  This kind of makes sense because the engine opens the wastegate fully and then closed it when you turn the ignition off.  But I don't know whether it learns the voltages in the process.  The advice in SSP485 is "After replacing the module, the new module must be programmed via Guided Fault Finding / Guided Functions."  But I don't have the kit for that.

 

On a test drive the stuttering was still there - accelerating uphill in third from about 1,600 revs.  But it didn't seem as bad.

 

I'm getting some high-temp grease following the advice here, as I found connector at the end of the shaft dry and I'm sure I greased it a couple of years ago.  (It is behind the heat shield.)   On the 1.2 TSI it is not possible to adjust the length of the actuator shaft as it appears to be on this 1.4 TSI.

 

I need to try recording the charge pressure as TheClient suggests but my OBD II dongle is misbehaving.  I think I tried this once before but it was inconclusive.  I wonder if these sensors ever go wrong.  Or if I'm completely misdiagnosing this?  Might it be worth getting hold of VCDS to use the "guided functions" feature to recalibrate?

 

Any ideas?

Interesting.  Ok. I don't have experience of your engine / turbo so I searched a bit more.  I've done some reading. It seems like there are a decent number of posts about that combo regarding turbo problems and work arounds after garages recommend turbo replacement.

 

The actuator your engine uses is different to other turbos i've had in my vehicles. Also, there is no mechanical calibration possible as it is not threaded at either end. So it must be electronic calibration or nothing. That may support the turbo rebuilder response that said no calibration required.  Of course if you change the throw length by inserting a spacer, maybe some engine ECU parameter does also need to be altered with it. Not totally sure what though as the wastegate actuator operation is on and off only isn't it? 

 

Based on reading, the shim recall required reprogramming of the EPC at the same time. I don't fully understand why per previous paragraph - but was this done?

 

Have you considered replacing the actuator with a new unit to confirm it is not faulty actuators? Yes, boost levels at the revs your having problems at might help or someone with VCDS to log a run. It makes fault finding easier and less of a throw parts at it approach.  Have you looked at the VCDS member locator?

 

Failing that, there is one of the posts I have come across showing that after removing the heat shield, and the actuator, and the Vband clamp of the turbo it is easy enough to get access to the turbo waste gate itself and clean up the carbon make sure it is not sticking etc. 

 

This is assuming your turbo is a conventional wastegate set up not a VNT set up.  There seemed to be some confusion in some posts I saw but the photo that I saw in a thread was definitely a wastegate set up. What is your engine code and or series if you know it?

 

 

Edited 4 September, 20205 yr by TheClient

Hi TheClient - thanks for thinking this through, but don't let it bug you!  It's been bugging me since it first became a problem about 5 years ago.

 

So, answering your questions: The engine is a CBZB.  The shim was fitted in a recall and the ECU recalibrated at the same time, I presume.  It worked fine for a number of years and then suddenly developed this problem.  For a while it seemed to work better when I removed the shim.  I got a replacement actuator, and that definitely worked better without the shim, but now the old unit with the shim seems to be an improvement.

 

I don't think the wastegate is just open or closed.  Per SSP485 "If the nominal charge pressure has been reached, the wastegate is adjusted to the position required to produce the nominal/actual charge pressure."  I think the stuttering occurs because once the pressure has been reached the wastegate is opening too far and then the pressure drops and then it closes again.  So what I really need is to be able to log the revs, load/torque (or some proxy), the charge pressure and the wastegate position.  It's a normal wastegate, not VNT.

 

When the actuator is off it is easy to move the wastegate by hand using the lever the actuator rod connects to - and it moves freely.  I guess I could remove the cat to get more access to it, but I'm worried about introducing dirt to the turbine itself if I try to clean the wastegate.

 

I guess apart from logging some data, the next logical step is to find someone with a VCDS so I can use it to calibrate it.  It remains a mystery why it suddenly developed a fault.

 

I might not do this immediately, but I'll let you know.

Yes, that was a silly comment. Of course the wastegate can partially open within a fairly small range by the looks of that video.

 

I think unless you want to risk buying a new genuine (or OEM equivalent) actuator your only option is to get someone with VCDS to look with you.

 

Log RPM and boost pressure whilst inducing the fault. You may be able to do that with other OBD reader but VCDS is much fuller featured as you know.

 

If there are adaption values or a reset procedure in VCDS use that.

 

I looked at the posts you cross referenced as well as a good few others.  The thing that seems strange to me is that 1600 rpm would be a very low RPM for the engine to start regulating boost pressure by opening wastegate. Is there a good tension pulling the wastegate closed.

 

Have you got someone to turn engine on / off. Rev car so you can look at the actuator rod movement in operation in your car?

 

I'll leave you at it now. Best of luck getting it solved.

 

 

13 hours ago, unicyclerepairman said:

 

 

On a test drive the stuttering was still there - accelerating uphill in third from about 1,600 revs.  But it didn't seem as bad.

 

 

 

On 05/09/2020 at 00:22, unicyclerepairman said:

Hi TheClient - thanks for thinking this through, but don't let it bug you!  It's been bugging me since it first became a problem about 5 years ago.

 

So, answering your questions: The engine is a CBZB.  The shim was fitted in a recall and the ECU recalibrated at the same time, I presume.  It worked fine for a number of years and then suddenly developed this problem.  For a while it seemed to work better when I removed the shim.  I got a replacement actuator, and that definitely worked better without the shim, but now the old unit with the shim seems to be an improvement.

 

I don't think the wastegate is just open or closed.  Per SSP485 "If the nominal charge pressure has been reached, the wastegate is adjusted to the position required to produce the nominal/actual charge pressure."  I think the stuttering occurs because once the pressure has been reached the wastegate is opening too far and then the pressure drops and then it closes again.  So what I really need is to be able to log the revs, load/torque (or some proxy), the charge pressure and the wastegate position.  It's a normal wastegate, not VNT.

 

When the actuator is off it is easy to move the wastegate by hand using the lever the actuator rod connects to - and it moves freely.  I guess I could remove the cat to get more access to it, but I'm worried about introducing dirt to the turbine itself if I try to clean the wastegate.

 

I guess apart from logging some data, the next logical step is to find someone with a VCDS so I can use it to calibrate it.  It remains a mystery why it suddenly developed a fault.

 

I might not do this immediately, but I'll let you know.

 

If you're referring to the older 1.2TSI (chain driven, EA111 engine), the Fabia MK3 forum won't be of much assistance, you'd have more luck in the MK2 forum.

 

Aside from that, have you ever had the chain tensioner, or perhaps the chain itself changed for any reason? I say this because timing chain stretch and tensioner failure is a known issue on those older 1.2TSI engines.

 

I recently had the timing belt changed on my EA211 1.2TSI (the newer, belt driven version of the engine), it was mistakenly done whilst the engine was still hot resulting in about a 4 degree advancement on the exhaust camshaft. The ECU was able to compensate with the intake cam as it's variable valve timing and it was not enough to throw any errors, but when the engine was at low loads, it resulted in too much valve overlap, poor air/fuel mix, and heavy missfiring.

They refitted it whilst cold, resulting in a 0.1 degree tolerance, and the engine is smooth as butter again.

 

Just to close this off.  I was completely wide of the mark.  It was either the plugs or the coil pack - I don't know which because I changed both.  I took it to David in Enfield to benefit from his VCDS, but I also benefitted from his experience and advice!  

@unicyclerepairman did changing the plug and coil pack fix the issue? i have the exact same problem. I have actually bought a new actuator and was about to change it tomorrow. Should i get a set of plugs instead?

 

@DominicSach Yep. A really helpful guy with VCDS diagnosed it as nothing to do with the turbo but as a misfire. I don't know whether it was the plugs or a coil pack, but changing both fixed it 100%. 

Thanks a lot. i will change them one by one and see if it will fix the problem for me. thanks again. Stay safe🙂

@unicyclerepairman hi, so the issue for me was finally found to be a damaged flywheel that was making the noise when the engine was on load. Got it replaced and now the engine is butter smooth. Just wanted to put this here and thanks  again for your inputs. Helped a lot to narrow down my problem. Cheers

Wow, was that a manufacturing defect? Sounds expensive, glad you got it fixed.