Do I have a boost leak?

[no-fear]

hi all,
For at least the last 12 months my boost had been peaking at around 23 then dropping off to 16/17, Over the last week it has been peaking at 19 and dropping to 15/16 and is holding at that.... am I likely to have a boost leak? or would the pressure keep dropping if it was leaking?
Not changed or done anything to the car, other than using the new shell V-power??? come to think of it I have also been getting occasional smell of petrol inside the car....

any ideas anyone?

Cheers!

 

[no-fear]

bump

 

[P-torque.co.uk]

If you have VAG-COM, do a log for both your MAF readings and your Boost.

You need a registered version to check boost, so its easier to have a look at your MAF readings first.

 

[warren_cox]

if its not holding its boost on full load acceleration there is a good chance you've got a leak.

my car was boosting to 29psi with Revo Stg2 on, and 27psi with it off. Once Stealth located a major pipe leak under the N75 valve, it dropped to 24psi with it on, and 11psi with it off. It would then quite quickly drop back even though my foot was planted.

I then checked again to make sure all other pipes were 100% and I found a hairline split on the hose going into the top of the DV (presume thats the vacuum hose). Once I had cut this pipe back I then peaked at 20-21psi with stage 2 on, and 9 psi with it off BUT held its boost under acceleration.

These small soft rubber hoses are exposed to a lot of heat above the turbo / exhaust manifold area of the engine bay, and to be frank they are shyte. If I had been keeping the car for much longer I would have investigated trying to insulate all the gubbins at the top of the engine. It inly takes a jubilee clip to be slightly overtightened and a split can start to form.

 

[no-fear]

Cheers for the replies guys....
Unfortunately I don't have access to vagcom, so would mean a trip to the stealers if I took this option. Strange thing is it that after peaking at 19 and settleing at 15/16 it is then holding and not dropping further under acceleration, that was the reason I wasn't sure if I had a leak or not....

Could any other factors lead to a drop of 3 or 4 in boost other than a leak?

Cheers again!

 

[Chaz]

you may have a boost leak, although 23 psi on a KO3s is pushing it a it hard anyway...

 

[cordobabrendy]

you havent changed to rubbish fuel recently have you? As I understand it, the ecu can wind back parameters if it detects knocking , in turn (again, as i understand it) this drops the boost a little to accomodate the timing knockback.

 

[no-fear]

I have changed fuel quite recently, but only from Optimax to V-Power, this does seem to coincide with when the changes happened to my boost, and also the smell of petrol inside the car.....hmmm, will have to try a different fuel and see what happens....

Cheers

 

[cordobabrendy]

regardless of what caused this, if i was you id try resetting the ecu also so that you are forcing it to re-adapt to your current fuel and style of driving etc.

 

[Big_daddy]

If you smell fuell in the car, check you injectors, for smell or sign of petrol.

 

[no-fear]

Cheers guys, I will have a good look around the injectors tomorrow, by resetting the ECU I take it you mean disconnect the battery for 30 mins? not done this since I had the car as I'm not sure if I have the correct stereo code, but will give it a try tomorrow.

Cheers fellas

 

[cordobabrendy]

30 mins is a bit long really, ive done it in 5 mins before simply by disconnecting it then opening the door and closing it a few times, this kills off the residual charge left in the system.

 

[no-fear]

OK, so I've reset the ECU, did over 100 miles for at work last night, included getting a flat tyre on one of the darkest and most haunted roads around, smell of petrol seems to have gone and didn't notice any leaks. But still 3-4 psi down on the boost, it's due a service which I am going to do next week so maybe cleaning the airfilter may help?!?

Cheers!

 

[no-fear]

I don't suppose anybody remembers this thread, but just thought i'd add to it, as my car is obviously haunted, nothing has been changed with the engine, yet the boost is back at 23psi... wierd!!!

 

[Big_daddy]

yeh i had similer problem also! i check the whole turbo piping and check the actuator but noting. i then gave up! around a week l8r the power came!

 

[Gnollins]

Perhaps this is the soft-limp-when-cold issue?

 

[no-fear]

Perhaps this is the soft-limp-when-cold issue?

Sounds like something I get when the wife gets in from a night out with the girls.....

 

[Gnollins]

Apparently a part of the stock Seat software (which remains active even after a remap) has a known issue:

If the engine temp is below a certain value when the car is started the ECU limits the amount of boost, and doesn't remove the limit even when the car's up to temp.

Now, on a stock map the reduction in boost is negligible, it perhaps drops the output by 10BHP. However, if the car's been remapped the power drop is far more noticeable.

According to Revo Kev the latest Revo code sorts this problem out. My LCR is suffering just now, I'm in the process of arranging to get the latest Revo code as mine was remapped back in 2003 (I have only owned it since August though, hence only noticing the difference with the recent cold weather).

Do a search for revo cold, cold limp or similar, I found quite a few topics from last winter about this!

 

[no-fear]

Cheers Gnolins
That's all starting to make sense now, I'll have a 'play' when the roads dry out, and see if the cold or warm start has any effect....

Thanks again m8

 

[Gnollins]

No probs mate

It's a 'kin annoying problem for us remapped dudes.

I'm hopefully getting the new Revo code on Friday. Will let you know if that fixes my issues.