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ojdaboostman 05-02-13 11:41 PM

Help!!Raw fuel in catch can
 
Has anyone had this happen, I installed the catch can between the oil fill and the turbo, blocked off at the uim. And the catch can fills up with raw fuel.! What can cause this, fuel leaking into the oil, evaporating into the catch can? Sometimes while driving hard, speed shifting into the next gear the turbo stalls out and I have to let the rpm drop down between shifts to let the control system catch up. This is the only oddity with the control system that could potentially aid in troubleshooting this. Any help is appreciated

bumpstart 05-03-13 02:14 AM

it may be siphoning oil up.. though the degree of dilution is a concern..
to do the evap system correctly there needs to be an "air break" or "air bleed" source from the other nipple on the filler neck

ie ..air path is as follows--
small rocker cover filter>one way valve > oil filler neck > catch/mist separator can > aircleaner on turbo


this makes a flow through ventilation system under only mild vacuum

if you have included flow from the charcoal can / fuel tank vent line then it should be teed between the filler pipe and turbo mist can
and if it is direct from the fuel tank vent line then should be teed between mist can and turbo air filter
( to minimise contamination of collected oil vapour with fuel )

note the basic theory is the same in all installs..primarily a FLOW THROUGH ventilation system first and foremost with a mild vacuum provided at the air filter

this is an emulation of the mazda intended high load crankcase ventilation pathway .. with a catch can

adding extras like charcoal filter / vent line and or a drain back from the mist can do not alter its purpose of design
.. apply thought and due process to your application with that in mind.. it is very tiring to answer this particular question umpteen thousand times due to domestic variation on the can or install
.. use your own nouse and sort it

misterstyx69 05-18-13 12:56 AM

maybe already answered by Mr Bumpstart,but it does sound like a can routing problem.
My theory/guess would be that you have the catch can going to the Vacuum nipple on your TB without a one way valve and when it hits boost then the Fuel goes into the can as Pressurized Air/fuel.
I'm strictly guessing,but it sounds good..no?

ojdaboostman 05-27-13 11:41 PM

Thanks for all the help guys, much appreciated, ill let you know how it goes.


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