Cupra R boost problems and traction light

[merrix]

Hi all, I'm new on here and now seeking advice!
The other day I was driving my SLC R (05) down the motorway in 6th gear and I thought the boost felt a bit odd, when you put your foot down to engage the turbo, it boosted up and gave me power but then the boost would fall away with a bit of a hiss, this was with my foot still planted, it would continue to fluctuate like this until I was going too fast and had to slow down,
then on a slight uphill section, I put my foot down to maintain speed, and with a large whooshing noise I lost boost followed by the traction control light coming on!
now the car drives ok when your not on the boost (under 3k revs) but as soon as the turbo starts to spool up there is no real increase in power just a lot of whooshing air noise. and now when you lift off your foot, it sounds like its got an aftermarket dump valve fitted.
Im going to be getting it to the garage tomorrow, but was just wandering if anyone might know if its something as simple as a split hose somewhere or if its much worse and my turbo is blown!
Many thanks!

 

[brad_barker12]

Sounds like faulty MAF sensor to me mate

 

[285cupra-matty]

But it also sounds like the boost your making is escaping somewhere maybe dv faulty?

 

[brad_barker12]

good point but bare in mind if he has the n249 plumbed in and the maf is faulty the ecu will tell the n249 to open the DV especially if the maf is making it overboost hence the air escaping noise

 

[googujube]

Might be an idea to take a good look at the hose coming from the charge pipe to the dv..

My TC light is on constantly at the moment, just this minute waiting for the MAF to dry after a good clean to see if that sorts it...

 

[merrix]

Ok, so having looked at your replies, I had a quick look under the bonnet and to my relief, I saw a loose hose, the on that comes from the DV back on to the big metal pipe with the no touch sign on it (excuse my lack of name knowledge) and I thought this would have fixed the problem.
The traction control light has now gone off which I believe is a warning for a boost leak so this would make sense. but when I took it for a road test, its still suffering from this weird fluctuation in boost, exactly the same fluctuation it had before blowing off this pipe, could it be that these two problems are connected or is it a huge coincidence
It is probably a good time to mention that the car is completely factory stock and unmodified too
Thanks again!

 

[brad_barker12]

the ESP light (traction control light) will come on if theres a problem with the maf sensor, one of the wheel speed sensors or sometimes a boost leak.

when the light was on if you turned the car off then back on again would the light go out at all?

check the hose you mentioned for holes and splits. its quiet possible your car has a boost leak but again its also possible the MAF has failed.
if the car is fully standard It might be worth you doing the N249 bypass. this will remove a lot of pipework and will eliminate that area for boost leaks.
it will take 5 minutes of your time, I used 4 meters of 4mm hose. there are lots of guides on here on how to do it.

to be honest it might be worth plugging it into diagnostics as im sure it would log a fault code where abouts are you from?

 

[brad_barker12]

also the stock DVs are known to fail which could cause the issues your experiencing

 

[Alban brown]

the ESP light (traction control light) will come on if theres a problem with the maf sensor, one of the wheel speed sensors or sometimes a boost leak.

when the light was on if you turned the car off then back on again would the light go out at all?

check the hose you mentioned for holes and splits. its quiet possible your car has a boost leak but again its also possible the MAF has failed.
if the car is fully standard It might be worth you doing the N249 bypass. this will remove a lot of pipework and will eliminate that area for boost leaks.
it will take 5 minutes of your time, I used 4 meters of 4mm hose. there are lots of guides on here on how to do it.

to be honest it might be worth plugging it into diagnostics as im sure it would log a fault code where abouts are you from?

Hi I'm having the Sam trouble but if I turn the engine of while still running it goes out you mentioned this but no answer to the question will it be a boost leak because I've ad a new mag for red

 

[Alban brown]

Hi I'm having the Sam trouble but if I turn the engine of while still running it goes out you mentioned this but no answer to the question will it be a boost leak because I've ad a new mag for red

Sorry new maf fitted

 

[borisvanhalen]

Had similar issues, boost is surging up and down / dumping boost

1 got a DV servicing kit from Forge which made a bit of a difference

2 undid the N75 and gave a blow on the connectors, this improved things a little

3 have ordered a new N75 - should have been delivered today, hopefully fit this tonight and see if it sorts the problem...

will keep you posted

 

[borisvanhalen]

Update...

fitted new N75 over lunch, took approx 20mins

main trouble was removing the 'single use' jubilee clips

anyway, went for a quick spin and seems to have cured it... didn't dump boost pulling away enthusiastically (was doing this before)
and seemed to hold it during some spirited acceleration...

will find out for definite on the way home later

... all back to normal, drive home (50miles of mixed motorway, and A roads) confirmed it was the N75

 

[Alban brown]

Update...

fitted new N75 over lunch, took approx 20mins

main trouble was removing the 'single use' jubilee clips

anyway, went for a quick spin and seems to have cured it... didn't dump boost pulling away enthusiastically (was doing this before)
and seemed to hold it during some spirited acceleration...

will find out for definite on the way home later

Think I have sorted mine was a small vacume pipe under inlet manifold just collapsing under vacume but the pipe goes to a valve on the engine breather so was not opening valve seems ok just boost is a bit high

 

[jt20vt]

I had a similar problem a few years back. Could be MAF or N249 (if stock), Boost leak or N75, even had the car smoke tested and checking all the others mentioned work good. In the end it was the boost pressure sensor and a dying MAF that caused the problem.

 

[Alban brown]

I had a similar problem a few years back. Could be MAF or N249 (if stock), Boost leak or N75, even had the car smoke tested and checking all the others mentioned work good. In the end it was the boost pressure sensor and a dying MAF that caused the problem.

We're his

 

[Alban brown]

We're his

The boost sensor located his it the one beside the battery on the plastic boost pipe thanks

 

[jt20vt]

The boost sensor located his it the one beside the battery on the plastic boost pipe thanks

Yep
sometimes the sensor will become stuck to the pipe so when i replaced mine i had to get a replacment pipe also.

 

[Alban brown]

Yep
sometimes the sensor will become stuck to the pipe so when i replaced mine i had to get a replacment pipe also.

Could you tell me were you got the pipe from I ad to stick new sensor back in so might not be right thanks

 

[jt20vt]

I purchased the pipe from my local TPS, or you can purchase it from SEAT VW AUDI parts dept in a local garage. You can get 2nd hand ones on ebay. I purchased an exact replacement along with sensor. The sensor is also reffered to as MAP SENSOR / MAP PRESSURE SENSOR.

 

[Alban brown]

I purchased the pipe from my local TPS, or you can purchase it from SEAT VW AUDI parts dept in a local garage. You can get 2nd hand ones on ebay. I purchased an exact replacement along with sensor. The sensor is also reffered to as MAP SENSOR / MAP PRESSURE SENSOR.

Ok thank you