Low boost on 8V92

[mike kerley]

8V92 that has started to loose boost. Max I now develop before a shift is about 7 or 8 pounds. Best I can do is 12 pounds locked in a lower gear at 2100 RPM. Changed filters (air and fuel)and tried a new sensor. Good fuel pressure and little black smoke, but no boost. I am seeing soot from around both exhaust manifolds, so guessing the gaskets are gone. Could this be the problem? Turbo turns freely and no DDEC codes indicating a problem. Florida Detroit has ordered manifolds but I'm questioning if this will solve my boost issue.

[Jon Wehrenberg]

Mike, see my post on the other site.

The manifold I have is the RH side (that is it is the LH side as you look at the engine from the rear of the coach). It does not have a pyrometer fitting but it can be added easily.

If you want it it is yours, but it may cost you a few cold NA beers.

[mike kerley]

Jon,

Just pulled out of the Florida Detroit shop and "wallah", mucho boost!

Both manifold were toast. The left one had a hose support bracket bolted to it which had broken a piece off and caused a great leak. Gaskets were leaking on both sides. Steamed the compartment, filled with fresh coolant and I'm good to go. Gotta order new Pyro probes, but otherwise it was complete. Expensive, but what isnt (7 hours labor, two hours fighting to get the old probes out of the old manifolds).

Sure runs better with a turbo!

[MangoMike]

Mike,

Does this mean your going to make POG?

TurboMango

[Jon Wehrenberg]

Good deal Mike.

Keep an eye on the turbo inlet pipes, especially around the flange where they attach to the cast iron manifolds or the area around the flexible portion on the one side.

They lasted about 12 years on my 87 and will cause the same problem, but it will be more exciting because the noise and black smoke and sooting is overwhelming.

If you lose turbo boost and there is no apparent manifold or turbo inlet leaks it might be the turbo boost sensor.

Can you guess why I know all this?

[mike kerley]

Mike, Nope. business calls. I'll be back in Florida on the 30th or 31st. afraid you guys will be gone by then.

Jon, I can guess how you've gained your wisdom. Expensive, isnt it?

Makes college seem cheap (well, it used to be cheap).

Best part was the large cloud of black smoke I blew out when i first pulled out of the shop.