1.9tdi problems

[iant8898]

First post - so please bear with me.

I'm running a 1.9tdi Mk1 Leon. It runs fine when driving it "normally" - ie not aggressively or like a granny. Turbo kicks in and it will rev freely in all gears (4k+).

When I floor the throttle however a fter a second or so the EML comes on and it goes into limp mode (I think) - although it will still rev to 4k+ eventually - just without the turbo kicking in.

I have a cheapo code reader and it comes up with "overboost" - and when reset its fine again.

Also, it occasionally goes into "limp mode" when driven sportily but the EML doesnt come on and there are no faults logged on the cheapo code reader.

Also, I have had it read with a garage reader and get the same indications - but wasnt VCDS

Can this be a turbo problem given that all is well if driven "normally" or should I be looking else where ? (just remembered, it had a new EGR valve before I got it - about 2k miles ago)

Any help would be gratefully appreciated.

Ian

 

[chriswales6]

Sounds very much like sticky vanes in the turbo, the car will normally drop into limp mode above 3k revs and goes away when you restart the engine. There’s lots of message threads about TDI turbo limp mode and over boost but a quick overview:

The vanes get stuck when the car is mainly used for short runs, less than 30 minutes. The turbo doesn’t get hot enough to burn off the soot and carbon.

A garage is likely to recommend a new turbo, the safest option for them since you won’t come back in a few weeks with the same problem.

The turbo normally responds well to a simple cleaning, this can be done a few ways.

Self clean (this is the option I used to stop my limp mode) just drive the car on longer journeys.

Clean the turbo without removing, there’re videos on YouTube search for turbo cleaning. It may take several cleans if the turbo is very dirty.

Remove the turbo and take it apart to clean, again videos on YouTube showing how to do this.

If the car is only used on short journeys even after cleaning the limp mode problem will return at some point.

 

[verbal_kint]

Does your reader give you an actual code that would be much more helpful.

Overboost can be caused by many things, clogged EGR - Clogged/Sticky turbo vanes... which I think would be a good bet.

Odds are that the old owner had the problem and had a new EGR put on (cleaning the old would have been so much cheaper but hey a mechanic needs to make money). The problem would have eased but likely they never checked the turbo for gunk.

Luckily the oven cleaner method works a treat if that is the problem.

Otherwise you could have a split vacuum pipe or faulty MAP.

Chris posted while I was typing...

So will add to his info that the turbo can be cleaned without removal, but if you do take it off it will also give you a chance to clean up the inlet manifold pipes.

 

[iant8898]

Hi - thanks for the input.

I did think it might be sticky vanes but the confusing bit is that its perfectly fine is not driving aggressively - it will rev smoothly upto over 4k so I assumed the vanes were free.

Would anything else cause this problem other than the turbo ?

 

[iant8898]

I'm doing a lot of motorway miles so I'll give it another week or so - do you recommend any additives to help clean the vanes ?

I'll change the vac pipes as thats fairly easy to do.

Its had a new N18 and EGR as the EGR valve was knackewed (it was my sons car before me and we tried cleaning it).

Its a 2004 car - does it have a MAP ? Looking at this pic I cant see one

 

[iant8898]

seatcupra.net/forums/showthread.php?t=189997

post #17

 

[chriswales6]

Fuel additives won’t really do much by the time they get to the hot side of the turbo, since they’ve been through the combustion cycle.

I have seen videos of turbo cleaners sprayed into the air intake. Personally I wouldn’t try that and if you did want to try then water would have similar result (that’s what most of the turbo clean is made from). The only way to safely help things along is to directly attack the hot side of the turbo and spray oven clean is an ideal weapon.

My commute changed to 60 miles a day on the motorway. After a couple of months the car was running better than it had for years and I haven’t had an over boost since.

I have a non PD 1.9 TDI 110 and the wire has been unplugged from the N18 EGR valve for over 11 years. Luckily my car is so old it doesn’t throw a fault code.

The turbo vanes are normally the problem, but if you can get the car scanned with VCDS it may help identify any other problems.

 

[iant8898]

Thanks for the reply.

Ill have a go with Mr Muscle when the weather perks up a bit - too bl**dy cold at the moment.

Mines also a 110 tdi (2004)

 

[Connorg115]

https://youtu.be/56oIU-sF7d0

Thought this might help

 

[iant8898]

Thanks - I'll have a go that

 

[chriswales6]

That's on the PD150 engine, he went in from underneath because it's easier than dealing with the EGR system on that engine.

On the non PD 110 you can do it from the topside through the EGR system. Like in this video:

https://www.youtube.com/watch?v=PbUAfzi5BdM&t=56s

Personally I try to avoid getting under the car as much as I can these days

 

[iant8898]

Cheers Chris - I'm with you about getting under cars

 

[Zardoz]

On the non PD 110 you can do it from the topside through the EGR system. Like in this video:

https://www.youtube.com/watch?v=PbUAfzi5BdM&t=56s

Personally I try to avoid getting under the car as much as I can these days

Think I'll give that a go myself, nice one Chris!