testing the AFC housing for boot leaks

[btoscano]

I am wondering about testing the AFC housing itself for boost leaks.





I disconnected the metal line to the manifold and connected a rubber hose to the line and pumped it up with a MityVac. It easily got to 5 psi but I could not use the MityVac to get it any higher. I had to connect the line to a cylinder of dry nitrogen and then I got higher readings. Is this the way its supposed to work?



I opened the AFC housing to check for tears, etc. and did not see any in the rubber diaphram.



Any comments would be appreciated.



Thanks,

Brian

 

[JLEONARD]

Pressure (from boost) goes in and forces the diaphram down against the spring. That spring pressure being adjustable via the star wheel (assuming the spring is still in there... some have removed it).

So I would say that from your description you tested the housing correctly. for leaks.

 

[btoscano]

Why couldn't I pump it up to 10, 15, or 20 psi with the MityVac?



The MityVac has a gauge that will head up towards 30 psi.



In fact when I used the dry nitrogen to supply higher pressure I used the MityVac to read that pressure.



Brian

 

[dpuckett]

I thought the MityVac pumped vacuum, not pressure? I dont see how it could do more than 5psi. But, that should be enough to test for leaks.



Did you get new springs with your rebuilt pump? What did they set the flow to?



Daniel

 

[btoscano]

The MityVac I have is can do either pressure or vacuum. I've used it as a temporary boost gauge as well. I just checked it, and it does NOT pump more than 5 psi of pressure. So, it seems that the AFC housing is fine.



Brian

 

[MMeier]

Does it hold the 5 PSI for several minutes? If so, I would say it is fine. I'm going to try to rig up something so I can test the intake from the turbo to the manifold for leaks, IIRC some got a sewer cap and put a valve stem into it and clamped it onto the turbo inlet and pumped like 20 PSI through it, sound right?

 

[btoscano]

Sewer caps, Campbell's soup cans, Beer cans, ... take your pick.



I am not sure about flow past the valves. If I was trying to test the intercooler and pipes I would cap off the end before it gets to the engine and see if it drops over time.



Brian