Help with turbo related issue

[kitcho]

Ok, so as of late i've been unable to build any boost. So far i've:

- Did a boost leak test and held 15psi just fine.
- Compressor wheel spins freely, no in-out play, a tiny bit of up and down play.
- I tried using a bike pump to test the wga, but it opened even under the slightest amount of pressure. I don't think this is normal.
- WG flapper moved freely without obstruction

When I try to build boost it gets to 0 vac and then basically falls on it face. It still builds revs slowly, but goes nowhere. Compare this to when i hold it at part throttle, avoiding boost, i can make it to high rpms and it's very smooth.

What i'm wondering is:

Could a resonably sized pre-turbo exhaust leak prevent me from building boost at all?
What should I do to determine if my wga is operating correctly.

thanks

edit: also now when i shift under "boost" there seems to be a whirring/fluttering sound that was never there before.

 

[Nate]

Any sounds like an exhaust leak?

 

[SmoothCustomer]

if there is a flutter it could be a coil pack that makes it seem like a boost leak. The flutter would be at fairly high rpm. Do you have a cop setup?

 

[atc250r]

Quoting kitcho:
- I tried using a bike pump to test the wga, but it opened even under the slightest amount of pressure. I don't think this is normal.



I would look into this first. Why not just wire the WG shut and take it for a ride? Of course you have to be careful that you don't overboost it but that'd tell you if the WG was the problem.

John

 

[SmoothCustomer]

^^Yeah my bad I would definitely try that first, but if that turns out fine, coil pack.

 

[kitcho]

Quoting atc250r:
Quoting kitcho:
- I tried using a bike pump to test the wga, but it opened even under the slightest amount of pressure. I don't think this is normal.



I would look into this first. Why not just wire the WG shut and take it for a ride? Of course you have to be careful that you don't overboost it but that'd tell you if the WG was the problem.

John



do you mean just cap off the vacuum port on the wga?

 

[atc250r]

Nope. I mean physically wire the WG flapper shut.

 

[kitcho]

^ ok, i did that. i left the vaccum to the wg connected. no difference.

i should mention the only thing i've done to my car recently is fix a boost leak at the bov by rtv'ing both sides of the gasket... nothing else really.

not really sure where to go from here. i wish i could get a sound of clip of the whirring/fluttering sound when i shift. sounds like an aftermarket bov.

 

[kitcho]

pretty sure i've found the issue:

fell off when i removed the heat shield


yeah...


I've got all the parts i need to drop the turbo and replace all my exhaust studs. I'm still looking for a local DSMer to lend me a hand, though. /ubbthreads/images/graemlins/frown.gif

 

[steve]

I don't think that explains being unable to make ANY boost though. /ubbthreads/images/graemlins/dunno.gif Did you try pulling the vac line from the WGA? With the stock WGA, the WG flapper will open at only about 7psi. It was probably easy to generate 7psi on the bike pump if it was hooked directly to the WGA.

 

[kitcho]

^i did and it boosts higher but the same gutless feeling is still there. it feels like it starts to build boost. it goes from -20 vac to about 3 or 4 psi on my gauge and just falls flat. and when i shift there's an unexplainable sound (that was never there before), like an aftermarket bov. i'm gonna go do a sound clip and post it up.

 

[RedTwo]

It's a shock wave travelling back down your i/c pipes and stalling your compressor wheel. The noise is then escaping out your air filter.

 

[kitcho]

here's a sound clip

clip link

 

[kitcho]

Quoting RedTwo:
It's a shock wave travelling back down your i/c pipes and stalling your compressor wheel. The noise is then escaping out your air filter.



...

what are potential causes for that?

 

[kitcho]

Quoting steveVR4:
I don't think that explains being unable to make ANY boost though. /ubbthreads/images/graemlins/dunno.gif Did you try pulling the vac line from the WGA? With the stock WGA, the WG flapper will open at only about 7psi. It was probably easy to generate 7psi on the bike pump if it was hooked directly to the WGA.



it seems like it tries to boost higher when i did this, but still that underlying completely gutless feeling.

on a side note, i did manage to build about 5psi today without it falling on it's face at part throttle.

 

[steve]

Hows the ignition system? Start with plugs, then wires, if unsure.

 

[SmoothCustomer]

^^told you. coil pack.

 

[curtis]

Also check the gasket between the turbo and manifold. If the head to manifold is bad you may have a compound problem of both.

 

[kitcho]

Quoting steveVR4:
Hows the ignition system? Start with plugs, then wires, if unsure.



Amazingly, it was doing it today but didn't do it when I got a Mitsu tech i know pretty well to drive it. It was pulling hard without issue for him. /ubbthreads/images/graemlins/banghead.gif

plugs are ngk's with under 2000 km's on them, i'll check for fouling and recheck the gap on thursday. plug wires are magnecore wires made for a cyclone manifold in really good shape but i will check them as well.

I've searched but I'm still confused - what tests should I do to determine if my coil pack is bad? Ignitor?

thanks

 

[kitcho]

i am such an idiot

when i washed my engine bay a couple weeks ago, it seems that some water made it into the #1 spark plug tube (this is atleast partly to do with the design of magnecore wires which don't cover around the spark plug hole, only on top) when i pulled the spark plug wire there was water on it /ubbthreads/images/graemlins/ooo.gif and finally it all made sense. dried it out and it's back to itself again feel free to have a laugh at my expense /ubbthreads/images/graemlins/banghead.gif