Vacuum Hose on the front of the IM

[waad_uk]

Just started to check a few of the small bore hoses over with the Mityvac.

The back two hoses hold vacuum no problem, but the front one will not hold any sort of vacuum. Is this normal?

Pauls diagram states that this hose goes to the Throttle Bypass Valve - Is this another name for the diverter valve?

Going back out in a min to check the WG diaphragm.

[newsh]

Yes, that goes to the diverter valve, so either the hose is worn through, disconnected or the DV has a hole in the diaphragm.

[waad_uk]

Yup the DV is leaking! Well that lasted 6 months (s3 one)

[waad_uk]

So...just to clarify. With the diverter valve removed from the car, and the mityvac on the small connection the top, should it hold vacuum?

Mine doesnt - I can hear air entering the large connection at right angles to the small bore connection.

It seems to hold positive pressure though?

[S2central.net]

SOunds like the diaphragm (or body) of the TBV is split... That link pipe from the IM to the TBV should be airtight... Theres actually a metal section of pipe that links two fabric covered pipes from the IM to the TBV.

Bung the vac pipe at the TBV temporarily then assure yourslelf with MityVac that the hose & metal pipe is indeed airtight.

Paul

[waad_uk]

Thanks Paul, Yeah both the hose and metal pipe is leak tight. Just a hideous amount of air leaking on the BOV.

I was looking at getting the heavy duty saab plastic BOV (its only £17) to replace it. Any experiences?

I did look around for forge valves, but limited places to buy it, and sky high prices!!!