Thoughts before I rebuild with new turbos!

[KMEL65STANG]

Problem: No Boost, No CEL and boost gauge reads about -10 at idle.

1st thought: Really bad boost leak

Tried:
1.Multiple boos leak tests ( holds boost every time, could not find and leak)

2.Replace n75 with MBC, no change.

3. Switched ECU's (for tune), no change.

4. Tested DV's, Holds evertime.

5. Found WG actuator a bit loose, tightened (so doors stay shut), no change.

The car smokes (not hella) due to bad valve seals. On test drives, I no longer hear turbos spooling.

2nd thought: New build

Which I'm already planning, but I hate to move along without learning how to find the root cause. Does anyone have any knowledge on other areas I could look at to learn what my actual problem is? TIA

[christianb5s4]

Does your car smoke at all times? Or only after you've been driving in vacuum for a while? Have you checked for a leaking valve cover gasket? That could cause a decent boost/vac leak since the heads are pressurized under boost and draw vacuum when not in boost.

[MetalMan]

Compression test?

[Zba]

-10in/hg? That is a mechanical issue unless your gauge is waaaaaaay off.

Does the car run like total crap?

Timing belt done recently and then magically no boost?

[KMEL65STANG]

Does your car smoke at all times? Or only after you've been driving in vacuum for a while? Have you checked for a leaking valve cover gasket? That could cause a decent boost/vac leak since the heads are pressurized under boost and draw vacuum when not in boost.

Smokes at idle all the time (now), but not excessively. Have yet to check valve covers. I'll check that this weekend.

[KMEL65STANG]

Compression test?

Haven't done that either, but it idles fine and accelerates well. Doesn't feel like any power loss other than no boost.

[KMEL65STANG]

-10in/hg? That is a mechanical issue unless your gauge is waaaaaaay off.

Does the car run like total crap?

Timing belt done recently and then magically no boost?

No, car runs fine. it use to hold at -20 consistantly. Timing was done about 15k ago. recently did a tune for about 24psi and ran very well until I took it to the track.

[Ribbie]

I had the same issue. Found out that one of the turbos parted ways with a turbine fin. Car would run fine, idle fine, just never go into boost.

[Royal769sr]

How does it accelerate well without any boost?

[KMEL65STANG]

How does it accelerate well without any boost?

Sorry, I meant it does not build boost as usual. On WOT , it builds up to about 2psi. max. So there's still a little vac. As far as accelerating well, It accels like a normal V6 without boost. No stutter or hesitation what so ever.

[Royal769sr]

Ohh ok. I got ya

Sent from my SGH-M919 using Tapatalk

[KMEL65STANG]

I had the same issue. Found out that one of the turbos parted ways with a turbine fin. Car would run fine, idle fine, just never go into boost.

This is what I was thinking as well.