lack of turbo boost?

[mordred1973]

suddenly my 2007 Leon TFSi seems very flat until 2300rpm when the turbo comes in with almost a bang, for the last 2 years its pulled incredibly strongly from 1500rpm (max torque is 1700 I think) even then it appears to have noticeable turbo lag which it never had before.

anyone got any ideas on what the problem might be?

I guess it could be a bad batch of fuel? do I run it til that tank has gone and refuel and see if theres an improvement or do I call the dealer now as it is still in its 3rd year warranty.

Suggestions would be appreciated :-)

[shark_90]

Have you ever changed the Diverter Valve while it's been in your ownership?

The standard Diverter Valve is a diaphragm type and easily splits which would cause it to lose boost.

Here's my standard valve:



You can imagine the amount of boost that held.... none!

Thankfully there is a new valve design which is of a piston type - the part number is 06H 145 710 D and looks like this:



If you haven't changed your Diverter Valve then you can almost guarantee that it'll still have the diaphragm valve on it and that it will be ripped or have a hole in it.

Hope this helps

[mordred1973]

hi Shark, thanks for the advice, no nothing has been changed unless its been a service item in either the 10k or 20k service (its done 27k)

where is a diverter valve? have never removed the plastic cover over the engine hence not a clue what it looks like under there lol

[shark_90]

The diverter valve is on the side of the turbo, it's not a difficult job to change it but if you car is under warranty I'd be expecting the dealer to change it for you FOC.

Perhaps print this post off and take it with you, it might help explain

[mordred1973]

yeah it has 7 months of the 3 years left, so u think thats the most likely prob?

[shark_90]

Almost guaranteed on the 2.0TFSi, it's very very common.

[mordred1973]

cool...thanks, will call the local Seat dealer on Monday then rather than carry on running til next tank of fuel and get it booked for a check up.....

[mordred1973]

well the dealer had the car on weds for the day, told me there was low fuel pressure so they cleaned out for fuel supply pipe from the tank and its all fixed....its deffo better than last week but considering max torque is at 1700rpm it still doesn't have the go it used to under 2500rpm....

so back to the dealer again I guess (thinking of trying to find another FR TFSi to take for a spin to compare just in case it's all in my head!)