Shuddering engine under load when engine warm

[Nobbler]

Have a Leon 2.0 TDI 57 plate, 3000 miles on clock, which started shuddering when engine had warmed up. You could drive through it and engine would surge again. Garage spent 3.5 weeks trying to find a cure, including replacing DMF. Seat told garage to stop work when they revealed I had a Tunit fitted (which garage disconnected on day 2) and it had invalidated warranty. The warranty says accessory must have caused problem, but after 3.5 weeks the problem was unknown! The ECU was recording no fault. Legal letter to garage still gave negative response, they want me to disappear. Am left with a £16K car which is worthless and impossible to drive. Fuel filter is black (new one is white), but fuel is clean. Independent engineeer from Carcheckers is convinced it is flywheel problem, eventhough this was replaced on day 2 of investigation. I have read VW/Audi have had recurring problem with them. MPG is ony 42, should be 50 , could problem be Lambda sensor? Remember goes well until warm!

Anybody help?

[RickT]

I would get onto them regarding that warranty..

You could try another dealer and see how it goes with them..

let us know how you get on.

Rick

[Nobbler]

Thanks Rick.

I'm gonna try to contact Head of UK sales at Seat who ironically had a Tunit fitted to a Leon in 2006, eventhough his colleague said he no longer has it attached. Hopefully he might lend a sympathetic ear. I think legally they can't void the warranty by speculation/suspicion alone. They said it was the gearbox that had been overloaded , when i believe the 170bhp FR has the same gearbox anyway! Seat assumed the gearbox without even driving the car and the service manager and technicians plus carchecker engineeer said it had bugger all to do with gearbox! Just using it as a get out.

Still left with a car that shows no faults on ECU but shudders when warm and can't be doing any good to drive!

Anybody had similar problem and know the cure?

Difficult to know where to start!

Ta

[Ben]

why didn't you remove the tunit before you went to the dealers? leaving it on was a silly thing to do, so was fitting it in the 1st place imo.

http://www.vwaudiforum.co.uk/forum/showthread.php?p=139545#post139545

[Pauloz]

To be fair, any tuning out of OE spec is a perfectly valid reason for rejecting a warranty. The DMF is tuned to a specific frequency and torque, hence why theres over 300 different DMF's out there.

[Nobbler]

Thanks Pauloz

Would the flywheel not be the same on the 170FR six speed gearbox. Also they replaced the flywheel after the tunit had been disconnected. Had a tunit on VW Golf 1.9 TDI for three years with no problem. The juddering on the Seat started 6 weeks after the tunit was fitted.

Interestingly the fuel filter is black with dirt yet the fuel in the housing is clear. Could some of the diesel which i believe returns from the engine via the filter to the tank be getting contaminated in the engine itself?

[Pauloz]

Will defiately be a different flywheel yes - even changing from 5 to 6 speed changes the vibration frequencies and therefore requires a different flywheel. It really is that critical.... hence why fairly easy to stuff up playing around with engine management :confused:

[Nobbler]

9th April

Car now sorted, after 8 weeks in 2 different garages. The problem was faulty spray pattern from no 1 injector. This was changed yesterday and the shuddering has gone - not Tunit related!