Alpine951

I have had an evolution diverter valve on my car for years. I am trying to track down a big vacuum leak and it is very elusive. is it possible it could be the diverter and how could I determine this. I don't know the actual function of the diverter.

shortyboy

a diverter valve is a bypass / recirc valve. I would check if the diverter valve is opening under idle, if it is, i believe you need a stiffer spring. Also check which type you have, either a piston type or diaphram type.

edit: you said EVO MS valve, so its a piston type. Make sure you have the orientation correct. piston facing the intercooler pipe is what i remember. also try pressurizing the system, will make finding the leak much easier.

Alpine951

not knowing much about what a diverter is supposed to do, but after now looking at my car it seems like the piston is supposed to open under idle, meaning under vacuum because the port is receiving vacuum (sucking ) which opens the piston and lets air flow through the diverter. I removed the diverter and sucked on the port and the piston moves to allow airflow through the diverter. Is this not proper? Also looking at the hard pipes and jpipe it seems like if it does open under idle then it isn't getting any other source of air that isn't meter'd by the maf. The only thing I can think of now looking at the diverter since removing it and looking at it is that the top cover screws on and has an oring under it that maybe was not on tight enough when I pulled all the intake stuff apart and put it all back together. Then again I never had any signs of leakage when I pressure tested it more than once last year and have sprayed brake cleaner everywhere to see if idle changes.


Its been a year of :b anghead::ban ghead:

black944 turbo

I have the same valve and mine will open when sucking on the nipple as well. For that matter so will the stock valve. As for direction, it is oriented just like the stock valve. The previous comment is not correct. The piston faces the j boot.

Does the valve seal against the body of the valve when closed?

shortyboy

there was a discussion about this a while back, cant find the thread. vendors will recommend different orientations. I ran both ways and found running the piston facing the pressure side / intercooler pipe ran better. its free to try and test and post your findings.