Turbo might have gone into limp mode!? help, thoughts please.

[JricardoVW]

Took my GLI into a shop for a wheel bearing replacement job, dropped it off at 9am and I was told that the car would be ready by 2pm ( really...they needed the car for 5 hours to replace 2 wheel bearings I though to myself) and 3 o'clock rolls up and decide to just go. Show up and the guy at the counter says "oh yeah the mechanic is out test driving it" I though okay because wheel bearings need to be test driven, and to my pleasant surprise I spot "the" mechanic in my car bagging the crap out of it, I thought huh that's quite the test drive. Get called up to the counter, pay my bill and go. I had just bought and installed a Forge Motorsports splitter valve so when I started my car and got going I notice the sound of the valve wasn't the same as it used to be so I stepped on the gas myself and...turbo struggled to make boost. Car is chipped (GIAC X+ software) and was running 20psi (at the turbo spike, faded down to 16psi in the higher rpm range) . Now the car barely makes 15psi and it fades down to 11psi. What are your guy's possible ideas as to what could be wrong with my car!? :( Turbo ran perfectly fine and now it's crap, and what's really odd about the whole thing is that there are no codes coming up on the dashboard. None! Some help and some insight please you guys.

[BolideVW]

Re: Turbo might have gone into limp mode!? help, thoughts please.

Boost leak? Could be small enough to not cause any actual drivability issues, but enough to lose boost. Loss of boost could make sense for the sound of the DV.

[JricardoVW]

Re: Turbo might have gone into limp mode!? help, thoughts please.

Thanks man, is it something that can be diagnosed with the VAGCOM or do I have to take into a shop to get an actual boost pressure test?

[JricardoVW]

Re: Turbo might have gone into limp mode!? help, thoughts please.

BolideVW so I went for a drive, notice the boost gauge and when I'm driving and let off the gas the vacuum side of the gauge sits at 21. But when it's at idle it'll sit at 17. And to be more accurate turbo doesn't even make the 15psi mark, it's more like 12!

[Spooling_turbos]

Re: Turbo might have gone into limp mode!? help, thoughts please.

Do you care to share which shop you took your baby to so we can all avoid it? Not cool.
I've had boost issues with my mk4 1.8t, but they were related to loose inter cooler pipe hosing. Do you hear a loud whooshing like an air leak from the engine bay? Plugging VCDS, checking for codes, and logging requested vs actual boost numbers would be a good start.

[BaggedGLI]

Re: Turbo might have gone into limp mode!? help, thoughts please.

Needing the time for wheel bearings is normal, sure it might not take that whole time, but there are other jobs in the shop too and things dont always go to plan. As a shop you never want to promise a time you can't keep. The test drive would be normal, every once and a while you get a bad part out of the box, its not often but you need to take all steps to prevent it from going back, also having it fixed you may notice a noise coming from somewhere else that isnt being covered up by a bad wheel bearing anymore. So that was in good practice, bagging on the car however was not.

Don't be too hard on the car, baby it till you get it fixed or you run the risk of over spinning your turbo and wrecking it too.

Best bet would be to smoke test it. Did you install the splitter valve the correct way? VW installs theirs backwards from the factory because they cant handle the boost.

[JricardoVW]

Re: Turbo might have gone into limp mode!? help, thoughts please.

Fair enough Collin...I should've just taken it to you guys! It ended up being a bad splitter valve which is just bizarre because I bought it the 28th of October so it's very new but it decided to crap the bed a few days in!? When I first installed it the turbo made boost just fine (and it sounded awesome), up until I picked the car up from the shop. I'm running my old diverter valve that's how I know. I went back and talked to them they are getting me sorted with the valve since I actually got it from them. And yes I wasn't impressed when I saw buddy driving my car the way he was. I installed the splitter valve laying on it's side (pressure in port, discharge port and one discharge port free for the hybrid set up) according to the DIY sheet that comes inside the box.
I won't be sharing shop names, you just have to beware where you are taking your car (lesson learned for me).

[BaggedGLI]

Re: Turbo might have gone into limp mode!? help, thoughts please.

That is really weird, I was running a splitter for years without problems and now its on another big turbo car and still holding up to my knowledge, I guess a manufacturing defect will do that.

I am happy to hear that they are dealing with it for you and I hope you get taken care of. Awesome customers deserve awesome service.

[JricardoVW]

Re: Turbo might have gone into limp mode!? help, thoughts please.

Thank you guys for the shared knowledge, much appreciated!