cdl engine problems

[betts]

I currently own a prefacelift mk2 Leon cupra which I've just had to replace the engine due to a piston melting and scoring the bore anyway I've replaced the engine with a cdl engine from a golf r, everything's been fitted and it's running ok but when I come to a stop the revs will rise up to between 2-3k rpm and then slowly fall back to a normal idle, I've also had an engine management light pop on and the car has an intermittent missfire, it will be running fine and the then for a few seconds it will be like the cars running on 3 cylinders and then it's fine again. Any ideas guy because after spending 3k on the car I was expecting for everything to be fine

[EddieA]

have you checked the pcv?

[phem0r]

have you checked the pcv?

+1 for this

[edd666999]

Which map sensor did you use?

[betts]

I just changed the block, I believe all the sensors havnt been changed

[edd666999]

I just changed the block, I believe all the sensors havnt been changed

Do some forum searching, I remember something similar with a cdl engine and it was that a different sensor was needed depending on ECU.

[betts]

Sorry to sound dumb but what's the pcv?

[betts]

I just changed the block, I believe all the sensors havnt been changed

Do some forum searching, I remember something similar with a cdl engine and it was that a different sensor was needed depending on ECU.

Sorry to be a pain but have you got any idea what sensor will need changing?

[mdmay]

can you get a vag com scan done. where are you in the country?

[betts]

Nottingham mate

[edd666999]

I just changed the block, I believe all the sensors havnt been changed

Do some forum searching, I remember something similar with a cdl engine and it was that a different sensor was needed depending on ECU.

Sorry to be a pain but have you got any idea what sensor will need changing?

From memory I'd guess the map sensor...but I maybe wrong.

[martziniuk]

I just changed the block, I believe all the sensors havnt been changed

Do some forum searching, I remember something similar with a cdl engine and it was that a different sensor was needed depending on ECU.

Sorry to be a pain but have you got any idea what sensor will need changing?

From memory I'd guess the map sensor...but I maybe wrong.

Yeah it's the map sensor but you only need to change that if upgrading from a car that previously had a K03, the Cupra has a K04 as standard so should have the 3 bar (I think it is) map sensor.

[betts]

The golf had a dsg gearbox if that helps. I thought with the cars revs rising after coming to a stop it may be fuel pump related but I havnt got a clue, I'm at the end of my tether 

[Hurdy]

Yep, needs logging to determine the fault. There are quite a few faults that could do similar to what you are describing, including the runner flap position fault or throttle body fault to name a few. Unless it is logged and you get a code to work from you could just end up doing needless work.

[john87]

The PCV is the Positive Crankcase Ventilation valve.. it controls the amount of vacuum present in the crankcase, in other words it's a more sophisticated system than cars which simply feature a breather pipe which links into the air intake pipe.

If your PCV fails, you may experience rough running amongst other symptoms.