Curious Limp Mode Problem

[pavlf]

Hello my 59 Octavia 1.6cr has started dropping into limp mode, but only under very particular circumstances: revving past 2800 under load, but only in 3rd, 4th and 5th (so slip roads onto the Mway sometimes). Turning off the engine resets to normal. Otherwise it's completely fine. Fuel use is great, drives nicely. However, no one wants to hold back when overtaking on an A road so took it to garage to get the fault codes read. I was dreading either EGR or Turbo overboost/sticking (thinking of this I've filled it with turbo/egr cleaner, I put Wynn's in and garage put some other stuff in). Most of the faults that came back were related to fuel rail pressure and fuel pressure regulator. There were three other mystery codes, 10158, 10160, 10116. Garage deleted all the codes, went out for a drive and the mystery codes never returned, however, now when going into limp mode the engine management light also came on. After a few goes running it and then turning the engine off that went out. Also it seems that the fault is taking longer to replicate. 

 

The plan is to run it till most of the fuel has gone and then replace the fuel filter and see how it goes after that. Meantime, has anyone had a similar issue and does anyone know what those mystery fault codes are - it seems probable they also relate to fuel rail pressure. What might be causing this? Is it something that might be caused by a blockage? 

[Gissin]

sounds like sticky vanes

 

cant find those codes on rosstech?

[pavlf]

Thanks, yes, searching on here initially left me thinking sticky turbo vanes, but the fuel rail pressure faults maybe say otherwise? I've found a couple of the mystery codes and they also point to a fuel pressure issue. I think I'll run the additives through, change the fuel filter and then see what's what. It's only last week I finally managed to get the 'bulb out' warning light to go! It's like the car needs some extra symbols illuminated on the dash. 

[Redfab]

Does the 1.6tdi cr have the same variable vanes in the turbos as the old 1.9 tdi pd engines? I have had that on my old golf, with sticky vanes but not yet on the 1.6tdi cr.

Has your car had the vw emissions "fix" software update? may be worth checking as thats caused quite a few problems. 

You can do a simple search online and put you vin into the skoda website to see if its had the fix or not.

[pavlf]

Not sure if it has the same vanes, but it's definitely an issue that comes up with the 1.6cr. It hasn't had the software update. I wouldn't let them do it! Anyway, for now, I'm going to drive it until the tank is almost empty and will try not to do any hard acceleration in the top gears. It's absolutely fine driving around normally. I really hope there isn't a fuel pump or turbo problem brewing. 

[Redfab]

wise decision with the update.  With my old 1.9 tdi pd vane problem I used additives, mainly forte, and gave it a good hiding which did it the world of good.  Never fully went away though.

I hope i dont get the same problem with the 1.6 cr.  I do now believe they need regularly driven hard to blow out the crap.  I didnt do that with my 1.9 early on and im sure thats how i got problems.

 

Always use premium diesel now too as thats a massive difference in my opinion, but dont want to start a discussion on the differences between premium and standard diesel as its been done to death.

Edited 13 December, 2017 by Redfab
Premium diesel info.

[pavlf]

I think you are probably right about giving them a blast every so often. I've been driving around far too gently in order to maximise fuel consumption (and using supermarket fuel!)

[pavlf]

Update: ran some DPF cleaner through the system twice, drove it a lot at high revs, changed fuel filter and now it's all good.