Losing boost

[Rodie121]

I have a mk2 tfsi and I believe I'm loosing boost, I have checked live data under boost specified and actual pressure

The specified at full chat is 2100mbar
But the actual is at 1780mbar

I have checked the diverter valve and that's fine

I had a problem a while back where my actuator rod broke on my turbo I took it all apart and welded it back up and it's been fine ever since but I do believe I may not have adjusted the rod correctly and I suspect that is the reason why I am loosing boost,


Does anyone know how and where the rod should be adjusted too? Please help as I want the full potential from my engine!

Thanks Roddy

 

[betty_swollox]

I'd change the DV anyway, just cos you can't see a tear, doesn't mean there isn't one!!

 

[Rodie121]

I have just changed it and it's made no difference sorry I didn't note that

 

[betty_swollox]

I have just changed it and it's made no difference sorry I didn't note that

I'll let u off then


Hope u get it sorted

 

[Rodie121]

Really could do with a hand on this asap as car is in pieces

 

[betty_swollox]

U on the mk5gti forum??

Probs get a decent response on there mate

 

[chr1sd]

The adjustment on the rod sets the load on the actuator spring. If its not pre-loaded enough, the wastegate will open under normal boost pressure (hence why its leaking boost). so when you welded it, you could have lengthened the rod slightly.

You could try adjusting the rod / nut. Just go 1/2 a turn at a time.

 

[Rodie121]

Thank you very much for your reply and everything you're saying sounds right! I guess I will have to turn it half a turn at a time.

Also I've read about the PVC vavle playing up but would that cause that much lacking in boost

 

[Joshkcupra]

Failed PCV would certainly put a dent in your boost!

 

[Rodie121]

How can you tell if it's failed?

 

[Joshkcupra]

The car runs like dogshit for starters, and two I believe you can run the engine and then unscrew the oil cap, and if it sucks the cap down then it's generally a sign of a knackered PCV

 

[Rodie121]

Hmm mine seems to be running fine, have you done anything to yours?

 

[Joshkcupra]

I replaced mine with the latest revision as it was faulty

 

[Rodie121]

What are your thoughts on the PVC reamp from revo

 

[chr1sd]

disconnect the plastic pipe from the inlet manifold (the other end goes to the PCV valve). Wipe it clean and have a good blow down it You shouldn't be able to blow through it as the PCV valve should close. If you can blow down the pipe, the valve isn't working.

the fact that you have welded the actuator rod and then you have lost boost kind of tells its own story really.

Never adjusted one on the TFSI before so not 100% sure how the actuator rod attaches to the waste-gate on the k03/k04. On my cosworth, the actuator rod had a mounting hole on the end which slid over the end of the waste-gate. On the cosworth the general rule was to make the rod short enough so that you have to pull the rod onto the waste-gate by 1/2 the hole (if that makes sense). This gives pre-load meaning the waste-gate is forced closed.

When you welded it, you shouldn't have been able to just weld the two sections together without any spring resistance as above. hope that all makes sense

 

[Rodie121]

It could be that the rod is in the correct position, the car still pulls well but after I put a s3 intercooler on it and a sports cat I was expecting some sort of increase but it doesn't really feel like it, I think I may just check the PVC valve out as course of action then look at the rod. Don't suppose you're going to gti inters this year Chris?

 

[cheungy]

It could be that the rod is in the correct position, the car still pulls well but after I put a s3 intercooler on it and a sports cat I was expecting some sort of increase but it doesn't really feel like it, I think I may just check the PVC valve out as course of action then look at the rod. Don't suppose you're going to gti inters this year Chris?

Sounds like the rod to me...whatever was done, the boost leak is coming directly from the turbo but err best take it to a vw specialist somewhere local to you? We normally advise DV as they can rip/tear/crack and then it would be the PCV... have you checked your intercooler pipes or the discharge pipe (next to your turbo)

 

[Rodie121]

All that is checked yes, I've noticed a lot of vaccum when I remove the oil filler cap? Pcv

 

[Rodie121]

Also what do you think it should be boosting at ? It's revo stage one

 

[Rodie121]

Chris I've just done what you've instructed on the pcv valve and I can blow through it so I'm assume it's ****ed