04 TDi - Is it the Turbo? - roscoman

Hope someone can throw some light on this problem.

I bought an '04 Seat Toledo TDI SE (110bhp) about six months ago with a tiny milage of 4,500 miles.

About 3 weeks later, I noticed the car to be hesistant/misfiring between 1500 - 2000 rpm on light throttle - especially when cold.
When the car is warmed up, the problem is still there, but not as evident. Maybe misfire is too strong a word, but there is a definite stumble/stutter within this rev range.

Anyhow, its been at the Seat dealers quite a few times. To date, the MAF sensor, EGR valve, and EGR solenoid control valve have been replaced, but the problem has not been resolved.

No fault has ever come up in the car's ECU memory.

Next, an independant mechanic discovered that disabling the EGR solves the hesitation - happy days!! However, he could give no reason as to what might be wrong, other that the ECU was faulty, and holding the EGR open too long.

Finally, another garage might have the answer. They reckon the turbo is sticking slightly. The action of disabling the EGR results in increased exhaust gas pressure, which is able to overcome the turbos resistance to spin. I can follow their logic, but I just want to ask around here, as this seems to be a rare problem.

Has anyone encountered this problem?

As always, your opinions are greatly appreciated.

Many Thanks,


Edited by Dynamic Dave on 18/08/2009 at 11:12

Seat Toledo TDi - Is it the Turbo? - David Horn
Have you tried giving it a good thrashing?
Seat Toledo TDi - Is it the Turbo? - Xileno {P}
I agree, especially given its low mileage.
This thread of mine may help:
Seat Toledo TDi - Is it the Turbo? - roscoman

Thanks for the replies.
Yes, I've tried this a few times, with no joy. Drove it in 2nd gear with the needle at the revline for 5/6 miles, and it made no difference.
I have had this problem now for about 7/8k miles, so its not going to go away - unfortunately.

Seat Toledo TDi - Is it the Turbo? - jc2
The amount of gas going thro' the EGR is small compared with the amount coming out of the engine and EGR does not operate at wide throttle opening so it won't have an effect.
Seat Toledo TDi - Is it the Turbo? - roscoman
Yes, I agree.

However, this only happens on light application of the throttle - if the car is driven with a heavy right foot, then there is no problem.

Afaik, the EGR only opens on mid throttle, and is closed at tickover and on heavy acceleration - however, I'm not a mechanic, and my theory on EGR operation could be flawed.
Seat Toledo TDi - Is it the Turbo? - WoodyMike
I have a 150bhp TDI Sport with 58,000miles, and it has the same problem. A slight kick when increasing slowly from low revs. A real anoying problem. Have you sorted yours yet?

I was wandering about the throttle pot being worn.

Best regards

Seat Toledo TDi - Is it the Turbo? - Roly93
Assuming this car has a VNT turbo (variable nozzle), I would say that a possible explanation for these issues is the varaible-vane mechanism on the turbo sticking. These are small flaps all around the turbo impeller which open (by means of a vacuum actuator) to allow exhaust gasses to spin up the turbo. It is not uncommon for these vanes to get sticky with soot and gunge or possibly in your case, lack of use.

I would try disconnecting the actuator and giving the vane mechanism a good work-out by hand to try and free things up, and then giving the car a good 'Italian tuneup'.