Surging / Holding Back On Acceleration

[200bhp]

I have a 1.8T Cupra and its always felt that I haven't really got 180bhp.

I noticed on hard acceleration the power seems to surge then hold back then surge every one or 2 seconds.

Whats the most likely suspect, sticking wastegate ?

What boost pressure should it be running ?

Thanks

 

[Havok316]

I had a similar problem since i changed all 4 coilpacks and used decent spark plugs it seems to have fixed the problem. They were the factory coilpacks and had done 62k miles which is bloody good as for boost pressure im guessing about 18/20 psi on a k03s.

 

[200bhp]

Hmm my car has done 120k....

I guess I can start with plugs but it didn't feel like a 'spark' problem more something cutting the power in and out, its not kangarooing or anything.

I doubt a passenger would even notice but it feels like its being held back.

 

[Mr OCD]

18/20 psi on a k03s.

No chance... its more like 8psi on a standard KO3s ... stage one remap is around 15-16psi

 

[200bhp]

I found that Bosch plugs were fitted.

I changed them for the correct ones and it has certainly improved but is still there.

 

[200bhp]

Digging up an old thread....

Haven't used the car for a year...

Changed a faulty coil but surging is still apparent.

Having googled it seems the N75 valve is the likely suspect.

I presume Euro car parts sell them (although they aren't listed online)

 

[mattfas]

hi mate i know what you mean mine does the same im sure its the n75 valve there 60quid off ebay for the genuine one ill be getting a new one after christmas does it do the surging in higher gears 5th or 6th when accelerating hard

 

[KatCowie]

I also have this problem, but mine only ever does in in 2nd gear and mainly when not accelerating hard, only when using light throttle.

 

[TimJK]

Mines, turbo lag lol

 

[jammycupra]

Mine was like this, it was the PCV pipes located under where the dipstick is. Worth having a look, I knew one of mine was split as one of the pipes had an oily residue around it.

 

[quattrojim]

mine does this as well, just had it mapped and when accelerating in 5th and 6th it feels like the power builds and then cuts out, then gives another burst, then cuts out again and so on.

are there any other possible reasons for this?

 

[TimJK]

mine does this as well, just had it mapped and when accelerating in 5th and 6th it feels like the power builds and then cuts out, then gives another burst, then cuts out again and so on.

are there any other possible reasons for this?

thats like overboosting... my mates fabia vrs does the same since mapped

 

[quattrojim]

cheers for reply, can i do anything to stop it doing this?i still have standard tip, thought that could have had something to do with it but maybe not then.

 

[TimJK]

well, n249 could be worth bypassing, or speaking to who ever mapped it as if its only since then it could be the map

 

[Mashburn]

N75 valve?????

I'm only having a guess going by the fact that this controls boost, so i could well be wrong!

 

[TimJK]

yep this controls the boost, and by doing an n249 bypass, you are disconnecting the n75 valve anyway.

 

[gezmeister]

Just wondering - mine also does this, and several people have said about changing the maf. Should i do the N249 bypass first?

 

[jonesy118]

I had this and it was my PCV hose, but it was the Y-shaped one rather than the ones under the inlet manifold. Check out my thread week or so ago http://www.seatcupra.net/forums/showthread.php?t=247056

 

[gezmeister]

I had this and it was my PCV hose, but it was the Y-shaped one rather than the ones under the inlet manifold. Check out my thread week or so ago http://www.seatcupra.net/forums/showthread.php?t=247056

Cheers mate, ill check my breathers tomorrow

 

[BoomhaueR]

My car has the same symptoms but I have done the n249 bypass. It seems to be down 5psi on boost too. Should I reconnect my n249 and hence n75 to see if it runs better? I think I might have a boost leak somewhere but vagcom disagrees apparently :s