Odd "Exhaust Leak" Plus Knock

[sleepydsm]

About 2 weeks after putting on a new mitsu MLS gasket, and a freshly machined and rebuilt head, I did a WOT pull, 5th gear, 30PSI (Big load).

Around 5k RPM, I get a noise that sounds like an exhaust leak, and my CEL comes on (set for knock on Link) (There are not stored DTCS, so it isn't a real CEL). MY paranoia says omfg, maybe it's my really old used regular ARPS stretching/ head lifting... BUT I have no over heating issues, or KNOWN coolant loss.

Let's pretend my turbo collector gasket was blown out. And with enough backpressure makes this noise. Is that exahust leak upstream of the 02 sensor gonna eff with anything? That probably doesnt matter though as the car at WOT ignores the o2 sensor and goes off what the tune for LINK is, right?

I haven't done much digging. This noise only happens with a load, revving the engine cannot recreate this.

Any ideas? Other than that, the car drives normal w/o any issues. I have someone that will buy the car as soon as I get this fixed!


Thanks! See ya at the cookout!!

[4g63tcrazy]

I'm not gonna help you since I do not want you to sell the car.

[Halon]

Id say just check all the exhaust gaskets, maybe make sure the O2 is tight. Just do the simple checks first.

Do you have an external wg? could the sound be related to that since your only hearing it under load?

[sleepydsm]

When I get home from work, I will be poking around, make sure the WG is tight, etc, and there isn't any obvious leaks.

[4g63tcrazy]

I had the same issue before and it ended up being the manifold to turbo gasket. Whenever I would hit boost and do a pull you could hear it leaking.

[CarPsyco84]

You sure its not a boost leak? I had a coupler leak that sounded like boosted exhaust leaking...

[sleepydsm]

Update.

Felt a good side exhaust leak at 02-turbine housing flange with hand. Pulled off turbo, the gasket is effed on there. O2 Housing bolts not tight at all, and my Tial MS-V 38mm wastgate is internally loose. The v-bands and housing are good, but the top part where the diaphram is is loose. Took it all apart, and the diaphram has a tiny rip started in it but no all the way through. The press-fit valve bushing was coming out just a tiny bit also... I took a 2x4 and pounded it back in. All G now. Just waiting on a new Diaphram and gaskets, see if the issue is corrected.

[CarPsyco84]

Told ya it was just an exhaust leak...

[sleepydsm]

Originally Posted by CarPsyco84

Told ya it was just an exhaust leak...

I'm paranoid, but I'll know when it's fixed! This is the only thing keeping my car from being sold.