LCR Intermittent Boost Loss - Sticking Waste Gate?

[Lee M]

Hi Guys,

I have a mapped (phase 1) LCR and up until recently it has been running fine but now I seem to have a spurious boost drop, which I can see on by boost gauge.

Normally the boost spikes to about 20psi (1.38bar) and then it backs off to a steady 15 is psi (1.03 bar), over the last few days it has intermittent time where it only boosts to 8 psi (0.55 bar) and wont go any higher.

It lasts for about 5 mins and then the boost returns? this happened twice on my trip out this lunchtime.

Does this sound like the wastegate sticking open? By passing most of the boost around the turbine impeller?


Thanks all

I'll Vag-Com it tonight to see if there are any faults. I'll also try and work out how to do some logging!


Cheers

Lee

 

[acyv]

Hi Guys,

I have a mapped (phase 1) LCR and up until recently it has been running fine but now I seem to have a spurious boost drop, which I can see on by boost gauge.

Normally the boost spikes to about 20psi (1.38bar) and then it backs off to a steady 15 is psi (1.03 bar), over the last few days it has intermittent time where it only boosts to 8 psi (0.55 bar) and wont go any higher.

It lasts for about 5 mins and then the boost returns? this happened twice on my trip out this lunchtime.

Does this sound like the wastegate sticking open? By passing most of the boost around the turbine impeller?


Thanks all

I'll Vag-Com it tonight to see if there are any faults. I'll also try and work out how to do some logging!


Cheers

Lee

Yes man, this is causing because of wastegate. The spring of waste is so much soft, need to replace with harder one in order to see high turbo pressure on gauge. I had same problem with my Cupra and yesterday we have replaced wastegate spring with harder one. Will see the results these days. If needed, EVC will be pretty better also.

 

[Rocky Rocastle]

personally I wouldn't say you need to upgrade the wastegate as said above, Forge do one but I don't think you would find it's the problem, your standard one should cope on a mapped only car, this may be nakered but and it may need replacing though, as Bill advised me can you get a pressure test done on it or can you log the car to rule out other things

 

[acyv]

Over map we can give command to boost 2 bar peak (even 2.5 bar with emulator) and 1.5 bar continuous but due to stock wastegate's spring, it's releasing the pressure that's why over 5000 rpm boost is going down to 1.1 bar which is a mess. What must i do?

 

[Rocky Rocastle]

as said you might want to do a log for actual versus requested boost but it wouldn't register above 2.5 bar with a standard MAP sensor. (from my ltd experience i don't think it does anyway) or you under the impression you have more than this ?

 

[acyv]

as said you might want to do a log for actual versus requested boost but it wouldn't register above 1.5 bar with a standard MAP sensor. (from my ltd experience i don't think it does anyway) or you under the impression you have more than this ?

up to 5000 rpm peak 1.8 bar, continuous 1.4-1.5 bar, over 5000 rpm it's going down to 1.1 bar even 1.0 bar. Over remap it's commanded for utmost pressure but wastegate is not allowing for that.

 

[acyv]

You mean MAP SENSOR? or MAF SENSOR?

 

[Rocky Rocastle]

i did mean MAP but i think i misunderstood you, it's hard to say and it's a case of second guessing really, have either of you got access to vagcom

 

[jamiebennett81]

perform a static pressure test on the actuator to check it is holding what it should be

is it 0.7bar on a standard one?

also if it is intermittent, could it be a boost pipe collapsing as this is a very common issue, especially on mapped cars

pipe to inlet manifold and TIP are the most common pipes for this to occur

do you drive, get a hesitation, and then it boosts?

might want to check the N75 as well, could be faulty