Turbo cuts out after 80mph!

[RVP09]

Hi guys,

I've recently started experiencing a problem with my Leon (2004 Cupra TDi). When i'm driving it on the motorway in 5th or 6th gear, and try to accelerate beyond 80/85mph, the turbo cuts out and stops working, i.e. the car still stays running but the turbo does not kick in at all. When this happens, I have to switch my car off for a couple of minutes and re-start it and then the turbo works again as normal, except if i try to take it above 80/85mph again, the turbo stops working again.

With local driving, the turbo is absolutely fine, works as it should. It's just on motorway journeys where I try to take it over that speed.

I don't know if this has got something to do with it, but a couple of months ago, my engine cover/sump cover underneath the car fell off, so I took it down to the garage and just had it taken off.

Does anyone know if this could have caused any problems to my turbo? Or any help on what the problem could be would be great.

Thanks in advance..

 

[Muttley]

Limp mode. Get someone with VAG-com to check the codes logged on the ECU. Most likely causes are sticky turbo vanes (vanes don't open up as far as they should, leads to exhaust gas flow getting too fast, and overboost) or sticky EGR valve (sticks open when it should shut at high revs, leading, once again, to overboost).

If the fault codes do indicate overboost, try disconnecting the electrical connector from the N18 valve, the one that controls the EGR. You'll get a light on the instrument cluster, but if this cures the fault then it is almost certainly the EGR valve. Clean it or replace it.

 

[RVP09]

Limp mode. Get someone with VAG-com to check the codes logged on the ECU. Most likely causes are sticky turbo vanes (vanes don't open up as far as they should, leads to exhaust gas flow getting too fast, and overboost) or sticky EGR valve (sticks open when it should shut at high revs, leading, once again, to overboost).

If the fault codes do indicate overboost, try disconnecting the electrical connector from the N18 valve, the one that controls the EGR. You'll get a light on the instrument cluster, but if this cures the fault then it is almost certainly the EGR valve. Clean it or replace it.

Holy hell. Half of that went way over my head.

So, in layman's terms, I need to get it checked out by a garage? lol Sorry, i'm not at all technically minded.. how much will it cost to get to get the EGR valve cleaned/replaced? and it's sticky rubo vanes, how much will it cost to get those sorted?


Also, what about this sump cover? Should I get it stuck back on?

Cheers

 

[Art0ir]

Holy hell. Half of that went way over my head.

So, in layman's terms, I need to get it checked out by a garage? lol Sorry, i'm not at all technically minded.. how much will it cost to get to get the EGR valve cleaned/replaced? and it's sticky rubo vanes, how much will it cost to get those sorted?


Also, what about this sump cover? Should I get it stuck back on?

Cheers

I would have the thought the cover protects quite a bit as I've seen they cover alot more than just the sump

 

[RVP09]

I would have the thought the cover protects quite a bit as I've seen they cover alot more than just the sump

Oh ok, cool. I'll get it put back on anyway.

So, any ideas on costs to get this problem sorted mate?

 

[RVP09]

Anyone?

 

[jonjay]

It could be a number of issues. If your going to try and fix it yourself I would firstly replace the MAF. If that doesnt resolve the problem then again get someone to VAGCOM the car for fault codes.

 

[RVP09]

It could be a number of issues. If your going to try and fix it yourself I would firstly replace the MAF. If that doesnt resolve the problem then again get someone to VAGCOM the car for fault codes.

What is a MAF?

 

[Muttley]

The undertray is not likely to be connected with your limp mode problem, although there is a small chance it knocked the turbo vane actuator when it came off.

The undertray cuts down on noise, both outside and inside the car, helps protect the bits at the bottom of the engine from spray, stones and gravel, and improves the aerodynamics giving a little bit of gain in drag factor and improving the engine bay ventilation and cooling. However, lots of people on the forums have said they have left it off and no ill effects have been reported.

A service center will charge up to £60 for reading the codes logged on the ECU and giving their advice about what it could cost to fix it. I'd guess half a day's labour for either job, plus parts.

The MAF is the Mass Air Flow sensor, in your air intake. It's one of the items that gets reported on here a lot for failure, and failure usually causes a limp mode. The symptoms you're describing don't sound to me like MAF failure, though. Reading the fault codes will tell you if the MAF is failing.

Your failure sounds like the one I had on an old TDI 90 Ibiza, which was EGR valve related. The ECU detects too much boost in the inlet and reduces the boost for all throttle settings, hence the feeling that the turbo has gone missing. It hasn't, it's just dialled back a bit, enough to keep the car running so you can limp home - hence limp mode. The ECU has several different limp modes depending on what failure it detects.

Most limp modes get reset once the car has been turned off, like rebooting your computer, and reappear when you provoke the failure again.

 

[darkhorse]

If you aren't technically minded, you're better off taking it to a good VAG specialist, they will diagnose the problem in a few minutes and give you a list of options. It can be a number of things from a simple split hose to turbo vanes sticking or a clogged up EGR valve.

Hoses will cost £50 +/- £20 depending on which it is + labour.
Sticking turbo and egr are a little more tricky in that the garage can give them a clean whilst on the car which may solve the problem or you can get the turbo reconditioned at more expense.

I think the egr should give a warning light on the dash if it has malfunctioned though

 

[RVP09]

Thanks for your responses chaps.

Has anyone here got a VAGCOM and lives in or near Birmingham?

Cheers

 

[oldman]

i live an hour away, which isn't great.
try a request in the vag-com request section, will get a more suitable nearer friendly face