Boost problem

[KatCowie]

I have a 53 plate leon cupra and lately I have been feeling that the car is not running as it should be. It's hard to describe but here goes!
It feels as though it's boosting when Im not trying to, and is ALWAYS in 1st and 2nd gear. It boosts for about 2-3 seconds and then you hear the release of air, then goes back to what it should be like. Im not that clued up when it comes to cars but could it be the MAF? Im grateful for any advice.

 

[Willie]

Get a RR done, that will help, lol

Sounds like either a sticking DV, boost leak, PCV split hose or dodgy MAF
VAG com will help pin point this

 

[KatCowie]

lol, thanks for the advice!! Will get it on vag com at the weekend when my bro comes home.

 

[Willie]

Get your brother to log revs actual and requested boost, this will show up boost leaks.
Get him to scan for fault codes. A physical check for split hoses.
Perhaps jack up the front end of the car and SLOWLY accelerate through the gears with the bonnet open to see if you can pin point any leaks or problems

 

[KatCowie]

Ok, thanks. Hopefully find out whats wrong, he's a mechanic so should think he should lol.

 

[sweet1]

hi,did you find prob with boost leak,i have a 53plate cupra with what sounds like exactly the same prob,what were your findings?

 

[KatCowie]

No findings Im afraid. Put my Vagcom on and nothing. But Im swapping the standard diverter valve for a dump valve, see if that makes any difference. Will keep you posted if I do find anything.

 

[turbin]

I think I know what you are about. This happens around 3000rpm right? In that case its your map.

 

[jamiebennett81]

funny you mention this, the exact same issue is happening with mine

as if a surging, part throttle and it hesitates and jerks about as if it wants to boost fully, making for a very jerky ride at times

I will check the DV tomorrow

 

[KatCowie]

Yeah, about 3000 rpm. I don't have a remap, do you mean maf?

Any help appreciated! Good to hear Im not the only one with this problem.

 

[KatCowie]

funny you mention this, the exact same issue is happening with mine

as if a surging, part throttle and it hesitates and jerks about as if it wants to boost fully, making for a very jerky ride at times

I will check the DV tomorrow

Thats exactly what it is. It's really annoying.

 

[turbin]

Yeah, about 3000 rpm. I don't have a remap, do you mean maf?

Any help appreciated! Good to hear Im not the only one with this problem.

no, it might be the way your remap is written. It releases boost around 3000RPM's to limit torque. I went for a much more agressive remap and now mine never opens.

 

[jamiebennett81]

Yeah, about 3000 rpm. I don't have a remap, do you mean maf?

Any help appreciated! Good to hear Im not the only one with this problem.

around the time the turbo starts to spool (well a bit earlier in fact)

I have ordered a Forge DV kit, get that all serviced to reduce the problem

 

[turbin]

this here is what I mean. On the graph there is stock, medium map and aggressive map. See only the aggressive map keep the boost passing 3000rpm. We did 5 runs on each map and they where consistent.

 

[adam cupra 20vt]

My car did excatly the same thing after fitting my FMIC, it sometimes opened the DV just as it came on boost about 3000rpm but only did it on a light throttle?

I replaced my Forge 007p with a GFB DV last week and it doesn't do it now [touches wood]

 

[KatCowie]

My car did excatly the same thing after fitting my FMIC, it sometimes opened the DV just as it came on boost about 3000rpm but only did it on a light throttle?

I replaced my Forge 007p with a GFB DV last week and it doesn't do it now [touches wood]

Thats exactly it. My car is comletely standard so can't blame any parts ect.
I have just ordered a 007p, great Hopefully won't cause any more problems. Thanks everyone for your help, very much appreciated

 

[jamiebennett81]

Thats exactly it. My car is comletely standard so can't blame any parts ect.
I have just ordered a 007p, great Hopefully won't cause any more problems. Thanks everyone for your help, very much appreciated

it wont be the 007p

hundered of other members on here run this setup without any of the symptoms as you describe above

either its a failing DV you have (if its the standard bosch one) or a boost leak somewhere

 

[adam cupra 20vt]

I cured mine by replacing the 007p I'm not sure why as its only done about 1000 miles but replacing it with the GFB has cured the problem.......the 007p does seem to work perfectly so I'm not sure why this is.

I think [only think] I have the GFB done up tighter so maybe the spring in the 007p was to soft although I'm still running standard boost.

To be honest I'm not sure if the 007p was at fault, it could well have been something like the N75 or the fact I have bypassed the N249......all I know is I don't get the problem with the GFB valve fitted

 

[turbin]

I'm boosting 25-26psi and I use the 007P with green spring. No leaks. I use it flipped 90 degrees so the return pressure is perpendicular to the spring. Works like a charm.

 

[adam cupra 20vt]

To be honest I don't understand why the forge valve is fitted like it is, surely by the design of the valve it would be better to run it in reverse?