Seat VW Leon TDI 110 Misfire

[Ricardo2007]

I own a 2002 Seat Leon TDI SE 110BHP and have had it for several years. It has always been serviced at a main dealer and has been totally reliable.

It has now covered 117000 miles and Mass Air Sensor recently failed. I changed this part with a 3rd party replacement from GSF. The typical symptoms of loss of power, no turbo etc were corrected, but I have been left with an annoying misfire.

If I pull away from a junction and change into second I get a misfire between 1800 and 2000 rpm the engine/turbo makes an ‘Err, Err, Err sound. After I pass 2000 rpm the car drives OK, if a little rough.

I have found if I start the engine and rev pass 2000 rpm the car will drive smother between this rev range.

I have changed the air filter, engine temperature sensor, fuel filter and the N75 valve. I have also run several tank fuels of fuel system cleaner through the engine. A Seat main dealer has also reset the ECU.

I would really appreciate any help with this problem.

Many thanks

 

[CHR15B]

Hmm... try disconnecting the MAF to see if it goes away? The replacement could still be faulty.

 

[Ricardo2007]

Hi CHR15B

Thanks for your comment.

How will the car drive without the sensor fitted?

Will it create fault codes in the ECU that will need resetting?

Ricardo

 

[CHR15B]

The car won't drive to its full potential, and may burn a little more fuel that normal but your only doing it for a short period (Maybe 1 - 2 miles) so you should be OK.

If the fault doesen't happen with it disconnected it may be an idea to try another MAF - if it does then you can look elsewhere (Loose boost pipes maybe?).

When I done this in my Toledo (Also, TDI 110) it didn't log a fault code.

 

[sssstew]

yep could be that the new maf is dodgy, its not unheard of.

also try swapping your N18 and N75 valves, they are right next to each other.

 

[Ricardo2007]

Seat VW Leon TDI 110 Misfire - Update

Hello

I have replaced the MAF with a genuine Bosh (refurb) sensor and the misfire has gone. But if I push the car in second or third gear 3-3500rpm I get a lot of smoke from the exhaust. On one occasion the ECU reduced power to the engine.

Mileage 117000

Any ideas?

Thanks in advance.

Richard

 

[sssstew]

Could be a boost leak somewhere. You mentioned that it went into reduced power mode (limp mode) once this should be logged into the ECU, so could do with getting someone with VAG COM on a laptop to check for faults and also fo some logging.
http://www.ross-tech.com/vag-com/cars/tdi.html

 

[Ricardo2007]

Hello all thanks for all your replies so far.

The refurbished Bosh MAF came from GSF (German Swedish French - Car Parts) Portsmouth. It comes with a genuine Bosh refurbished sticker and one years guarantee. When replaced the performance was much better than before. I did notice I bit more smoke from the exhaust under load. When the car was warm I thought I would go through the full rev range. This is when the cars power dropped. I have changed the N75 valve but I could not find a supplier for the valve to the left (N18?).

Does any one know where I can purchase replacement braded rubber pipes? These are the pipes that run between the various valves.

Many thanks

Richard

 

[Ricardo2007]

I have just run VAG-COM on the car and have found and reset the follow fault code.

Chassis Type: 1M - Seat Leon
Scan: 01,02,03,08,15,17,19,22,35,46,56
-----------------------------------------------------------Address 01: Engine
Controller: 038 906 012 FK
Component: 1,9l R4 EDC 0000SG 3357
Coding: 00002
Shop #: WSC 06441
VSSZZZ1MZ2R084574 SEZ7Z0A1485086
2 Faults Found:
17965 - Charge Pressure Control: Positive Deviation
P1557 - 35-10 - - - Intermittent
17552 - Shareware Version. To Decode all DTCs
P1144 - 35-00 - Please Register/Activate
Readiness: N/A


After resetting the fault code I took the car for a drive. It seems to drive a little better, but I think I may have heard a slight squeak when backing off the accelerator. It does not do this very often.

Any ideas?