Hi,

I'm having a turbo problem with my 05 149k mile Octy. Yesterday while pulling hard away from lights, I heard a small pop sound, saw a puff of black smoke in the rear view mirror and the Octy turned into a slug. A driveable slug but a slug no less.

 

No warning lights on the dash. Turbo still whirring as usual when the motor runs but has a different "sucking" type sound. No smoke from the exhaust. Turning ignition on and off does nothing different. Local mechanic ran a diagnostic on it late today and I have the following codes off him:

 

16683 - Boost Pressure Regulator

P0299 - Control range not reached

 

He has found no loose or split hoses, but the large bore hose visible at top left of engine collapses (gets sucked flat and stays flat) when the engine is running. It was right at the end of the day so that's as far as he's got, and is going to speak to his diesel expert in the morning. I said I would post to the nice people on the Briskoda forum and see if they had seen this type of problem before.

 

If this were a motorcycle and not a car I'd know the score, but I'm just not that familiar with turbo diesel car engines and the associated electronics!

 

Any pointers very much appreciated.

Regards,

Lube

It looks as if the engine is not getting air , the hose being sucked flat indicates the engine is trying to suck air but is not getting it,

Air cleaner blocked, intercooler blocked, something stopping the air between the filter/ turbo/intercooler /manifold.

I would disconnect the pipe that is getting flattened to check that the engine will run , then I would look at the filter first and work towards the manifold checking the air pipes are clear.

 

No I have not seen this problem before

Edited 2 September, 201312 yr by erindad

Thanks for the reply erindad. What you say makes sense.

 

The code P0299 - Control range not reached, is for "mechanical fault" with the turbo.

All a bit odd!

Back again. The hose that gets flattened (by vacuum) when the motor is running is the one that runs to the EGR valve. If I take that hose off the valve, it makes no difference to how the engine runs, just makes it louder. The butterfly in the inlet of the EGR stays wide open all the time - engine off, tickover or revved. With the engine off I can open and close the butterfly with my finger. Is it meant to open and shut depending on engine revs?

Slight amendment to the above EGR description. The butterfly is fully open on engine start and remains open whatever the revs. Turn engine off and the butterfly snaps shut for a couple of seconds, then pops fully open again with a sound like a ping pong ball being blown from a piece of waste pipe.

Normal? Abnormal??

I have seen this same problem with a 55-plate 1.9 Octy. After it was plugged in and came up with the "boost" error codes, the garage ordered a new turbo and was quoting silly money to supply and fit it. I looked at the car and came up with the same conclusion as erindad.

Starting at the air filter end, a carrier bag had somehow made its way into the intake pipe, ruined the air filter and blocked the pipe.

Pulled out all the bits of the now-shredded bag, and fitted a new filter, right as rain.

The error codes come up because the turbo is not developing enough boost, because it is effectively running in a vacuum. It can't blow air if there is no air to blow.

 

Hope this helps

 

P.S. As for the EGR valve, mine has been faulty for over 3 years, stuck open. As a result, my emissions have been getting cleaner with each MOT test. 216k on the clock, and basically fresh air coming out the back

Slight amendment to the above EGR description. The butterfly is fully open on engine start and remains open whatever the revs. Turn engine off and the butterfly snaps shut for a couple of seconds, then pops fully open again with a sound like a ping pong ball being blown from a piece of waste pipe.

Normal? Abnormal??

 

The throttle valve function is correct for a diesel engine. On a petrol the valve moves in relation to the pedal request, but diesels run on "full air" all the time.

The valve closes when you switch the ignition off to stall the engine to make it stop.

A collapsing boost pipe suggests the engine is starved of air, as suggested above by a blockage. Many moons ago I had a collapsed air filter causing the boost pipe to cave in.

Thanks for the replies guys! It's encouraging that we all think that the problem is a blockage somewhere, but my knowledge of the system is failing us at this point unfortunately. I think I need to get  a Haynes just for a diagram. I think I know the theory of how it all works but fail to see how the plumbing hangs together. It is my first engine with a turbo and most of those were motorcycles anyway.

 

So, as I stand in front of the engine bay with just the engine cover removed:

 

1) There is an air intake at right side of grill. This has a large bore hose that goes into the airbox. There is a large bore hose that comes out of the airbox, goes to the right of the block and heads around the back of it, disappearing out of sight. I have so far checked that there is no blockage in the intake, the connecting pipe, the airbox (filter only 2k old, clean and intact) and the top of the airbox outlet.

 

2) There is a large bore hose that runs around the left of the block and this is the one that collapses once the revs go up. It runs from the butterfly valve of the EGR, left of the block, turns into a solid plastic snake of a pipe that goes down to near the bottom of the radiator, heads right, then either ends or connects out of sight near the bottom right of the rad. Is this the boost pipe? And where does the none EGR end connect to? I do not understand where this pipe terminates or gets its air from. If I knew that I might find what's blocking it!

 

3) Taking left hand pipe off the EGR makes no difference to current engine behaviour (apart from sounding super fruity). On the assumption that the left hand pipe is blocked, given the suction through the EGR butterfly and flattening of the pipe, the lack of air causes the Octy to be in slug mode. Removing the pipe from the EGR then gives it too much air and we get slug mode again even though it can now breathe. Does this sound right?

 

Many thanks for your help so far.

Regards,

Lube

Ok bought the Haynes. Understand how pipework routes around entire engine bay to get from air filter to intercooler to turbo. Now i can check more thoroughly for blockages. When I remove the intake pipe from the EGR I think the limp mode performance increases a little but not much. Is what I outline above at point 3) what you'd expect to be happening?

Had a similar issue on the Mk5 Golf. Same fault codes and performance issues but no pipe collapsing. Have you tried looking at the vacuum hose that is connected to the turbo actuator? Mine had several small cuts prventing the variable guide vane mechanism from functioning properly. Away with work until tomorrow, but will provide part no. or diagram to explain when back home.

Ok part no. 27 on diagram here is where I had issues:

http://www.partscats.com/skoda/en/?i=cat_vag_models&brand=sk&number=81&set=96&ein=2007&f=419&hauptgr=1234567890&hg=1&grf=013160409&bf=13160&hgug=131&ug=31&parent_id=102746

Diagram is not exactly how it appears but should give you a clue. The pipe connected to pt no. 29 was badly chaffed or split. May not be immediately visible, and you need to look from above and below engine.

Edited 4 September, 201312 yr by Black_Sheep

Thanks for the reply Black_Sheep. I know the hose you mean and will check tomorrow.

Got the Octy jacked up this morning. Took hot side boost pipe off the intercooler and a small puddle of oil dribbled out along with a couple of alloy chunks and some fine swarf. Looks to me like something has failed in the turbo, dumping oil and bits of it into the intercooler, which is now partially blocked, hence collapsing hose at EGR inlet. Looks to me like it'll need a new turbo and all the pipes and intercooler cleaned out.

Sound a fair enough assumption?

Chucks of alloy means new turbo for sure. If the turbo has jammed as a result, that could be what is causing the airflow problem, but while doing the work you may as well clear out the intercooler, and check it for leaks. It is probably fine, but flying bits of turbo could have damaged it a bit.

 

If you have lots of oil coming out, it could have come from the turbo, but these engines do burn a little oil. It comes from the breather hose on the top of the engine, which is connected directly to the intake pipe. There is a "filter" in the pipe which is supposed to stop this, but it is only foam and doesnt do much. Everybody I know who has these engines (20+ taxi drivers) uses about 1 pint of oil between services. Even the new 1.6 diesel engine does this from new, so a small amount of oil is nothing to be concerned about.

Just thought I'd check back in and say thanks for your help on sussing my TDI issue out. Recon turbo, new oil feed pipe and new intercooler and she's running great. £728 all in including labour so could have been worse.
Cheers, Lube.