Boost choppy/uneven and limited after remap

[mix]

Hi Guys,

Just had a stage 1 custom remap and my Leon Cupra is now running circa 210bhp on quite an aggressive map.

However, I have a problem.

If I push the car through the gears, using the revs it runs Ok

But if I say use the turbo when the engine is under load (e.g. in gear steady acceleration from say 2.5/3k to 5k) the car has little power and you can feel and hear the turbo spooling up and down, up and down erratically and it feels like its hesitating.

Almost like the turbo has a limiter!

I have spoken to the tuners who suggested that it may be the idle acuator, the n75 valve or even my stock DV.

The car was in mint service condition and used to pull smooth and steady through all revs and all gears!

Any thoughts really appreciated!

Cheers

Mike

 

[Mully]

two words that you just used "Stock DV", get yourself a Forge 007P and i reckon problem will be solved, the standard bosch dv's are very very very prone to failing

 

[Keith@APR]

Hi Guys,

Just had a stage 1 custom remap and my Leon Cupra is now running circa 210bhp on quite an aggressive map.

However, I have a problem.

If I push the car through the gears, using the revs it runs Ok

But if I say use the turbo when the engine is under load (e.g. in gear steady acceleration from say 2.5/3k to 5k) the car has little power and you can feel and hear the turbo spooling up and down, up and down erratically and it feels like its hesitating.

Almost like the turbo has a limiter!

I have spoken to the tuners who suggested that it may be the idle acuator, the n75 valve or even my stock DV.

The car was in mint service condition and used to pull smooth and steady through all revs and all gears!

Any thoughts really appreciated!

Cheers

Mike

Mike,

the first thing you can do to help us get a better idea of exactly what the issue may be is to provide a fault code scan of your ecu.

Do you have a check engine light illuminated? If so, we need that scan asap. If there is no cel on the dash, its still possible the ecu has stored a "soft code" which still warrants reading the ecu to find out what exactly it is.

With this info I can point you in the right direction.

 

[mix]

Hi guys thanks for your replies.

Took the car out just now and its still not playing ball, the dv appears to blow off louder and at low revs fluttered like a wastegate a couple of times.

Keith - No fault lights as yet and typically I have left my laptop and OBD kit at my parents. Will do asap though!

I had a feeling that it could be the valve not being able to handle the extra boost, as it appears to be when it is boosting highest that it stops and starts and it feels like its being held back, however the remap guys said they would stick with the standard DV or go with an Audi S4 twin turbo stock model, as they have had forge DV's stuck open in the past?!

The remap guys said to try disconnecting the acuator valve, on the back of the airbox, which of course generated a light on the dash, although it was my traction control light (! with an half circle arrow round the top)

Any additional advice before I take the car back for them to test it would be helpful as I have very limited time to get it fixed before I drive 400 across france!!

Cheers

Mike

 

[traumapat]

How old is the dv? Might be worth replacing it even if with the same new stock valve. The apr r1 is an alternative to the forge and is a beefier diaphram based version if you want to keep away from piston types.

Once you get access to vagcom you can log the car and see what the N75 valve is doing.

 

[Keith@APR]

Hi guys thanks for your replies.

Took the car out just now and its still not playing ball, the dv appears to blow off louder and at low revs fluttered like a wastegate a couple of times.

Keith - No fault lights as yet and typically I have left my laptop and OBD kit at my parents. Will do asap though!

I had a feeling that it could be the valve not being able to handle the extra boost, as it appears to be when it is boosting highest that it stops and starts and it feels like its being held back, however the remap guys said they would stick with the standard DV or go with an Audi S4 twin turbo stock model, as they have had forge DV's stuck open in the past?!

The remap guys said to try disconnecting the acuator valve, on the back of the airbox, which of course generated a light on the dash, although it was my traction control light (! with an half circle arrow round the top)

Any additional advice before I take the car back for them to test it would be helpful as I have very limited time to get it fixed before I drive 400 across france!!

Cheers

Mike

When you say actuator valve, do you mean the MAF? I can't think of a valve on the back of the airbox.

You can try the dv as it is the most common culprit. Our R1 as stated is a good alternative to piston valves. Piston valves require servicing and I believe forge recommends lubing every 3-5k miles.

I can't do anything other than speculate what the cause may be without those fault codes or a boost log as another poster suggested.

Sorry!

 

[mix]

The DV appears to be original, so 2003, and sorry yes keith I mean MAF!

Is there an easy way to test the N75 valve before I take it to the garage for Diagnostics, as after reading the forum in more detail it sounds high on the list of possibilities!

Cheers guys, really appreciate your help

 

[traumapat]

Did unplugging the Maf sensor make any difference?

 

[mix]

Didn't make any difference, apart from a light coming on, which spring should I use in a forge valve?

What are the benefits of an APR diaphram dv?

 

[traumapat]

The standard green spring in the forge will be fine.
The R1 has been very consistant on my car, no sticking and needs no maintinence.
It feels very smooth with it being diaphram based.

Forge 007p is a great dv but can stick if its not regularly serviced.

Both good dvs

 

[leon sport]

hiya mate,
iv got exactly the same problem with mine after remap,its so dissapointing int it,take it for the first spin after you have it done exspectin it to knck you bak into ur seat and instead your being pulled back an forth.i still havnt got to the bottom of it yet either need to spend alot of money aswell before i can .chip tuners who did mine all they said was get a new n75 valve(apperantly it doesnt allways come up with a fault either)clean out the throttle body and new wastegate,done all these bar the wastegate as its fairly new,but still no joy.
been advised that it might be the maf so this is the next step ill take,after new cambelt,tensioner,upgraded water pump and breather hose:w4nk:
sorry i cant really help with ur problem hope you get it sorted soon tho mate.