So in trying to find some causes for very intermittent but annoying restricted performance problems i thought it's time for a smoke test , all the usual culprits are sorted , donut pipes, throttle body seal and no signs of any weepage anywhere (inlet manifolds/donut seams). Did a bit of routing on tinternet for smoke testers but could not find out what is classed as high pressure , bought one (i can use it at work for other stuff afterwards so was worth it) that goes up to about 18psi, plugged it all in and no sign of any leaks , wipped map sensor out and plenty of smoke coming out of hole but one of the gauges was showing no real pressure build up indicating a massive leak , heres where my confusion kicks in
1 How can you pressurise the inlet system to show no leaks when multiple valves (inlet and exhaust ) will always be open allowing a throughflow of air/smoke.
2 Crankcase breather , not sure how they work on these (4.4tdv8) but i know it's something a bit more complicated than a standard PCV valve but i sure as hell pressurised the internals of the engine as it was full of smoke and oil filler cap went with a good pop and released all the pressure when i took it off .
3 How much pressure does a high pressure smoke test build up
Any useful advice gratefully received.