Hi all
as you may have read ive been having fun trying to fix my stuttering turbo, but i beleive i have fixed it now finally! after having the car for a year now. So i will summarise here what the problem was and how i troubleshooted and fixed it for future reference if anyone is searching for it and has the same prob :-
Problem :-
My car was very lumpy between 1k and 2k rpm, the turbo wouldnt spin up right, it would seem to stutter up, go up and down, this would make the car a bit shakey and make it surge. In the cold mornings you can hear the normal diesel gowl go up and down in volume. If u floored the accelerator it would smoothen out, but obviosuly its not preferrable to floor it all the time
Solution :-
it went into various dealers all of whom didnt have a clue as the computer didnt report any faults, but a MAF was replaced which reduced the severity of the problem slightly, but it still surged and the turbo just didnt spool up smoothly as on other TDIs.
so i swapped the N75 and N18 valves, the N75 is the boost control valve and N18 is the EGR control valve at the back of the engine bay, they are the same items but ones got a white cap and the others got a black cap. anyway when swapped over the turbo smoothed itself out and the car felt as it shoudl do, apart from mpg which was not as good, lost about 5mpg.
So i diagnosed a faulty N75 valve, bought a new one from vagparts.com for £65 and slotted it in and put the old N18 back to its rightful position. But this only returned the surging and dodgy turbo spool up for some reason.
To test i put the old N75 (which i thought was dodgy) in place of the N18 to control the EGR and lo and behold it worked a treat!! i now have a smooth turbo spool up, and hopefully my mpg should return, havent had chance to test yet.
So the result of this was that it was a dodgy N18 EGR Control Valve, cant explain why but this must have been putting in to much exhaust gas making it lumpy.
The key to this diagnosis is that when u floor it, the turbo smooths out, now as the EGR only works when NOT on full throttle this is why.
Anyway... im now a very happy TDI owner, after a year of not running right and alot of time and money wasted with dealers. I might even right a letter to Seat to tell them about it, so they know in the future.
A big thanks to all who have helped me with sorting this problem out, especially prc (paulo) much appreciated.
mine still doesnt soot though Ian
as you may have read ive been having fun trying to fix my stuttering turbo, but i beleive i have fixed it now finally! after having the car for a year now. So i will summarise here what the problem was and how i troubleshooted and fixed it for future reference if anyone is searching for it and has the same prob :-
Problem :-
My car was very lumpy between 1k and 2k rpm, the turbo wouldnt spin up right, it would seem to stutter up, go up and down, this would make the car a bit shakey and make it surge. In the cold mornings you can hear the normal diesel gowl go up and down in volume. If u floored the accelerator it would smoothen out, but obviosuly its not preferrable to floor it all the time
Solution :-
it went into various dealers all of whom didnt have a clue as the computer didnt report any faults, but a MAF was replaced which reduced the severity of the problem slightly, but it still surged and the turbo just didnt spool up smoothly as on other TDIs.
so i swapped the N75 and N18 valves, the N75 is the boost control valve and N18 is the EGR control valve at the back of the engine bay, they are the same items but ones got a white cap and the others got a black cap. anyway when swapped over the turbo smoothed itself out and the car felt as it shoudl do, apart from mpg which was not as good, lost about 5mpg.
So i diagnosed a faulty N75 valve, bought a new one from vagparts.com for £65 and slotted it in and put the old N18 back to its rightful position. But this only returned the surging and dodgy turbo spool up for some reason.
To test i put the old N75 (which i thought was dodgy) in place of the N18 to control the EGR and lo and behold it worked a treat!! i now have a smooth turbo spool up, and hopefully my mpg should return, havent had chance to test yet.
So the result of this was that it was a dodgy N18 EGR Control Valve, cant explain why but this must have been putting in to much exhaust gas making it lumpy.
The key to this diagnosis is that when u floor it, the turbo smooths out, now as the EGR only works when NOT on full throttle this is why.
Anyway... im now a very happy TDI owner, after a year of not running right and alot of time and money wasted with dealers. I might even right a letter to Seat to tell them about it, so they know in the future.
A big thanks to all who have helped me with sorting this problem out, especially prc (paulo) much appreciated.
mine still doesnt soot though Ian
