F355 Secondary air injection shut off valve opening pressure

Fix the vacuum system and you won't have a problem. Making it work correctly does not require modifications, it requires making it work the way it was designed. Also air injection check valves are a service item. They get ignored until rust prevents proper operation and often damages upstream components.

 

Don't know how that can be, those cars have been working perfectly since 1995 when they came out. Why is it now suddenly a faulty design? It is quite clear you do not understand how the vacuum system works. Go back to the books and figure it out.

 

I feel no need to prove the design works as built. Ferrari did that in 1995.

As for owing you something, you have a very highly developed sense of entitlement.

 

Thoight I would post a pic so you could identify which valve.

Correct me if I am wrong but you are saying the valve number 13 or 22 does not open. I assume you mean 13
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you need to check both valves and the secondary air pump for pressure. Just because you have opened that valve early does not mean the others work now.

Further more I dont understand how you were not getting a code from the car. Obviously your cats were not heating up as designed etc if the valve is not working.

This should have been your first clue.

Brian can correct me if I am wrong but that valve being stuck should not have effected the vacume.

What I also dont understand is if the exhaust valve was open from idle why would you have your gauges ready when no vacume exists initially. The valve opens with vacume if they are original and will only stick open if the valve is stuck open.

 

Also check your idle rpm to make sure it is correct.

 

Come on now Brian... Even you have to admit that's a pretty outlandish statement about a 355 or any other Ferrari for that matter. Thier engineers seem to have gotten plenty of things wrong over the years that took, at times, a very long time to be figured out and re-engineered. Way more design flaws than any large scale manufacturer would be able to get away with.

 

How the fu@k is my statement outlandish?

Can you identify a single design problem with the air injection system that prevents it's proper operation when it is working as designed and installed?





Yea, that's what I thought.

 

I love the way you jest, you're such a light hearted and funny guy. We can sit here and list Ferrari design and engineering screwups all night... Literaly. So it wouldn't be some massive, impossible shock if something not quite right with this or any other system comes to light.

 

This entire thread is about 355 air injection system function. If there was a problem with system design there would be 50 threads like there is about valve guides or sticky plastic parts. The cars are 22 years old and finding new engineering issues is long past.
Sorry for trying to stick to the subject.

 

I don't want to sound impolite, but honestly, I don't think anyone cares.

 

What is the purpose of the valve on the outlet of the pump?

Are the check valves on the manifolds weak enough to allow air to be drawn in via venturi effect if that valve was not in place?

 

Those are one way valves that allow fresh air to go from pump to exhaust but prevent hot exhaust gas from going back to pump.

 

Yes I know what the valves are on the manifolds, the question is why is there one also needed on the outlet side of the pump.

 

The valves at the manifolds are one way valves. Because of vacuum caused buy the exhaust gasses drawing air past them you still need to shut off air flow to prevent the O2s from seeing it as a lean condition. The valve by the pump is a shut off valve.

 

I think we understood that but perhaps James was asking why it's needed when the pump could just be shut off? (at least that is what I'm wondering)

 

Because shutting of the pump doesn't close the air path. I think Brian explained that Dave. O2 sensors who see excess O2. Also, if not shut off air could be drawn through the pump and it would start spinning like a turbine, adding to pump wear. A pump is basically a turbine in reverse. With a pump you apply shaft work and move the fluid and increase pressure. With a turbine, fluid flows from high pressure to low, and you extract shaft work.

 

John - the first part of your post is negated with the check valves at the manifolds, however, the second part makes good sense - thanks

 

Check valves only stop reverse flow.

There are many air injection systems with no pump. Exhaust extraction draws the air in unaided. Pump or no pump the air needs to be shut off. A centrifugal pump is just not going to do that job. It works like a water pump. Do you really think if the belt is off water cant flow through a water pump? You can see through it, no need to spin.

 

Got it - thanks - I was missing the exhaust gas draw...