328 can anyone indentify what this hose is

A pic would help--when can see exactly what your talking about.

 

A photo would help clarify the question, but if it's the line I think you're talking about, that might be one of the EGR lines. (Exhaust gas recyc.). Without loading the parts CD, I think there's two levels of vacuum enable for it and then the exhaust gasses are fed back to the intake plenum, to help with US emissions when cold. This is a US model?

 

I think that's what it is too

 

Never tried it, but it might blow exhaust into the engine bay. Dunno what the check valve (3) would do if the hose was gone.

But the hose (22) is easy enough to replace.
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Just to ease your mind, mine blew a few months ago right at the egr check valve. It sounded like a blown exaust gasket, but ran fine. When I got home I could see the hose dangling and when you put your finger over it the horrible noise went away. Again, remarkably it did not affect running. It was very tough changing, hose is very stiff and hard to remove. If I was you I would just wrap the hose with chafe tape.

 

At the last FCA Sebring Track Event a friend car had that hose blow and the hot exhaust gases burned right through the flywheel sensor harness and shut the engine down in a flash as he was just coming onto the back straight.

The harness is no longer availible from Ferrari so I built one as the end connectors were not destroyed.

The harness sits just below the hoses coming up from the bell housing.

 

sorry, don't have the hose diameter handy...

I think the system is air injection, not EGR. The airflow should be from the air filter box into the exhaust manifolds. If exhaust gas is going the other way, then the check valves (#3 - cheap GM parts easily obtainable) are stuck open.

Another symptom of leaky check valves is rotting of the metal T fitting (#8).

Anyway, since hot exhaust gases aren't supposed to be in the hoses, any hose will do.

If the hose wears through, you'd get more air into the exhaust stream, which would muck up the O2 sensor readings and the computer would incorrectly set the fuel mixture.

Sound right?

 

Correct. It really isn't an EGR valve but rather an air pump check valve-hose system. My check valve was rusted through...bought a new one at Discount Auto for $5.95!.....the cheapest repair I will ever have. The hose is of course a metric size. I was able to cut and re-connect. If you need hose try allferrariparts.com.

 

There's no air pump. The exhaust headers run at a vacuum relative to the intake air? Otherwise, how do they get air to "flow uphill"?

Hmm. I guess there'd be a vac at the header when the exhaust valve is closed. But there should be pressure at the headers where the valves are open. This is going to take some sketch pad time. (If each exh valve is open 244 deg out of 720 and there are four on a bank, ...)

 

Oops...meant to say air pressure-check valve system.