boost cut?

[tdi31]

well bit of an odd one this. I have recently downgraded from an evo 4 to this leon 110 tdi due to financial reasons, I know about boost cuts and fuel cuts having owned the evo 4. The other day on way to work only been driving probably not 5min come to a slight hill and was in 2nd gear and gave it some beans foot to floor and it hit 3000rpm and suddenly heard what I can best describe as a vacuum pipe blow off with a loudish dump sound and the car just died got me thinking with it being really early in morning and cold it overboosted? and boost cut on me, or was it a fuel cut? also after work car had been stood along time so was cold I turned TCS of and wheel spun it must have hit around 4-5k and it died again and it was really hard to fire it up again when it did was quite spluttery for abit

since these incidents its been driving ok and other night just to test my boost cut theory I had been driving it about 10min+ so should have been pretty warm and in 2nd put my foot down again got to 3k+ and it was ok didn't die.

so anyone any thoughts?

 

[Andrewcupra TDI]

could be limp mode

you would need to scan vag com really any errors /fault codes

sure someone with more brains than me will confirm

 

[Muttley]

tdi31 wrote

well bit of an odd one this. I have recently downgraded from an evo 4 to this leon 110 tdi due to financial reasons, I know about boost cuts and fuel cuts having owned the evo 4.

Well, that makes one of us, coz I have no idea what you are talking about. Please explain "boost cut" and "fuel cut".

Remember, too, that you are now driving a turbo-diesel, quite a bit different to a turbo-petrol.

The other day on way to work only been driving probably not 5min come to a slight hill and was in 2nd gear and gave it some beans foot to floor and it hit 3000rpm and suddenly heard what I can best describe as a vacuum pipe blow off with a loudish dump sound and the car just died

Well, that sounds like a pipe in the boosted part of the inlet system coming loose and blowing off, but it isn't the sort of thing that heals itself. The only other candidate I can think of is the EGR valve, which might provoke limp mode (loss of power, ECU reverts to a more conservative map after seeing an out-of-limits reading on one or more sensors) if it stuck open.

Or, could it have been the TCS cutting in? Was the road slippery? Did the car recover power straight away or did you have to turn the engine off and then back on,

got me thinking with it being really early in morning and cold it overboosted? and boost cut on me, or was it a fuel cut?

Nope, still gibberish. Under normal operation the turbo can't overboost, the variable geometry vanes in the exhaust turbine keep the boost under control. The ECU calculates injection quantities very precisely as this is the sole way of modulating power in a diesel.

also after work car had been stood along time so was cold I turned TCS of and wheel spun it must have hit around 4-5k

That is severe mistreatment. TCS doesn't work on these cars at rest. The redline is 4750 on the dial, but above about 4000 you aren't getting much power gain (peak power 4100) and just produce more smoke. Revving up to max while cold is a good way to shorten the life of any engine.

and it died again and it was really hard to fire it up again when it did was quite spluttery for abit

That isn't normal. You may have damaged the engine by mistreating it.

Diesels have a narrow powerband (2000-4000 rpm or so) and take longer to warm up than petrol engines, wasting less heat.

since these incidents its been driving ok and other night just to test my boost cut theory I had been driving it about 10min+ so should have been pretty warm and in 2nd put my foot down again got to 3k+ and it was ok didn't die.

Get it on VAG-com and find out if any fault codes have been registered.

 

[tdi31]

ok I guess I will get it on VAG COM so how much will Seat charge to hook it up to this to check?

 

[ChrisGTL]

ok I guess I will get it on VAG COM so how much will Seat charge to hook it up to this to check?

It will only cost you one leg for this service.

 

[tdi31]

It will only cost you one leg for this service.

well that could get quite painful if I have to keep going back.

 

[Muttley]

VAG-com is the name of a proprietary software package that you can buy to go onto your laptop, and with the aid of a special connecting cable (that has a dongle built in) you can connect to your car's OBD port (under the ashtray) and read fault codes, reset parameters and etc. If you're lucky a request on the VAG-com section of this forum may produce someone close to you with the kit who's prepared to come and help you out, fee to be negotiated between you (varies from say a beer or two to petrol, food and a beer or two

Dealers typically charge an hours labour for the equivalent, coneecting it up to their diagnostic kit and reading off the codes.