Smokey TDI Cupra

[sypher1987]

Hello all,

Ive just decided to treat myself and ive gone and bought a TDI Cupra, fuel economy and power what more could you ask for. It was fine on the test drive but since then ive noticed it gets a bit smokey when accelerating, also there seems to be quite a lot of pressure from the oil filler cap. It might be normal on these but ive never had one before so i really dont know. I have found that the airbox has been removed and replaced with a K&N cone filter but the maf is still there and fuel economy seems about right.

I might just be panicking cos the most ive spent on a car before is £600 and this time ive shelled out nearly 6 grand so im a bit nervous that somethings gona go wrong!

 

[AJ-V5]

Possible that it has been remapped, although it shouldnt necessarily be that smokey- unless its been done poorly.

When was it last serviced do you know?

 

[volvic]

i'd personally try and fit the standard air box as it was pretty good anyway.

i dont think it's always bad mapping as the guys/gals running big power here all have smoke. mine smokes when i in high gear near 2k revs. if i use the gears properly theres not much smoke. when mine was standard however there was no smoke

 

[rallynut]

EGR wants cleaing disconnecting probably

 

[Muttley]

Smoke on acceleration is normal, the EGR system adds to the smoke when a lot of power is demanded. Some remapped cars smoke more, although smoke is generally an indication that you are on the downside of the power curve.

The oil cap shouldn't be pressurised, the crankcase ventilation system should ensure negative pressure in there. Whoever fitted the aftermarket filter may have blocked off the breather - this is not a good idea. Fit a catch can if you want to keep the crankcase fumes out of the inlet, but let it breathe.

 

[sypher1987]

Cheers for the advice guys, I was planning to put an original air box back on as i dont like the cone filters, way too much heat soak in my opinion. Just gotta find one now, does anyone know if all the tdi air boxes are the same or will i need a tdi cupra one?

The guy i bought it from didnt say anything about it being remapped but is there any way i can actually find out?

Also, dumb question time, what is an EGR valve?

 

[Muttley]

Exhaust Gas Recirculation. An emission control device fitted to nearly all modern engines - but a kludge in my opinion.

Reduces NOx emission by feeding exhaust gas back in to the inlet to reduce the amount of oxygen in the charge and so reduce the peak combustion temperature. Its a horrible idea, but then catalysts aren't brilliant and we've all got those too . . .

Disconnection will not be detected at MOT, MOT doesn't test for NOx. Reconnect before a service or the garage will do it for you. With your engine it's likely that the ECU will notice and light the CEL on the dash display - the best answer for that is to get someone with VAG-com to turn the EGR to its minimum setting instead of disconnecting it.