Jimbobs Lexus IS200 Turbo!
Jimbobs Lexus IS200 Turbo!
Without the pcv connected my vacuum sits at -14 or -15 but when i connect the pcv it goes to -6 vacuum and i can hear the gases being sucked alot through the pipe
On reading im getting the impression that it shouldnt suck that much air through??
This is what i read
Because the engine idles at low speed there is a relatively small amount of fuel and air traveling through the intake. If the PCV valve did not regulate flow, the engine would act like it had a vacuum leak. Air flowing into the intake might cause the engine to lean out [too much air in relation to the fuel] and misfire. At an idle, the PCV valve restricts air flow, to reduce this problem.
At high manifold vacuum [idle], a spring loaded valve is drawn up and partially restricts flow to the crankcase. On acceleration there is far more volume of fuel and air moving through the engine. Intake manifold vacuum is also much lower. This allows the valve to move to a more central position, increasing fumes drawn from the crankcase. This produces far more removal of fumes, without affecting engine performance.
Should the engine backfire or if the engine is turbo-charged, the PCV valve can also act as a check-valve. Pressure in the intake would cause flow in the opposite direction. By closing the PCV valve, any positive pressure or fuel vapor is prevented from entering the crankcase. Even a very small amount of positive pressure can force oil passed gaskets and seals and blow gaskets out of place.
As the PCV valve ages several things can happen. Crud and sludge can cause it to stick in the open position. This might result in a misfire at idle. Too much air flow acts like a vacuum leak. Excess flow could also draw oil from the engine, causing oil consumption. A quality shop can test this using a tool called a manometer.
What people think?????
Jimbob-T-Lex
07-04-2020, 08:49 AM #834Had a gd read just now when i put the pcv valve into my inlet manifold it is sucking alot of air and the AFR goes down to about 11 instead of my steady 14.6
Without the pcv connected my vacuum sits at -14 or -15 but when i connect the pcv it goes to -6 vacuum and i can hear the gases being sucked alot through the pipe
On reading im getting the impression that it shouldnt suck that much air through??
This is what i read
Because the engine idles at low speed there is a relatively small amount of fuel and air traveling through the intake. If the PCV valve did not regulate flow, the engine would act like it had a vacuum leak. Air flowing into the intake might cause the engine to lean out [too much air in relation to the fuel] and misfire. At an idle, the PCV valve restricts air flow, to reduce this problem.
At high manifold vacuum [idle], a spring loaded valve is drawn up and partially restricts flow to the crankcase. On acceleration there is far more volume of fuel and air moving through the engine. Intake manifold vacuum is also much lower. This allows the valve to move to a more central position, increasing fumes drawn from the crankcase. This produces far more removal of fumes, without affecting engine performance.
Should the engine backfire or if the engine is turbo-charged, the PCV valve can also act as a check-valve. Pressure in the intake would cause flow in the opposite direction. By closing the PCV valve, any positive pressure or fuel vapor is prevented from entering the crankcase. Even a very small amount of positive pressure can force oil passed gaskets and seals and blow gaskets out of place.
As the PCV valve ages several things can happen. Crud and sludge can cause it to stick in the open position. This might result in a misfire at idle. Too much air flow acts like a vacuum leak. Excess flow could also draw oil from the engine, causing oil consumption. A quality shop can test this using a tool called a manometer.
What people think?????
Because the pcv is letting so much gases through its seeing it as a vacuum leak i think?
Jimbob-T-Lex
07-04-2020, 08:52 AM #835Well with the pcv not connected i get -14 psi so about 27 inHg
Because the pcv is letting so much gases through its seeing it as a vacuum leak i think?
![[Image: LexuS-Copy.jpg]](http://i65.photobucket.com/albums/h204/Sparkystav/LexuS-Copy.jpg)
Read my thread here: The Evolution of my Turbo Lexus from NA-Supercharged-Twin Turbo-Massive Single
Please leave your comments.
Sparkystav
07-04-2020, 09:08 AM #837Well I don't currently run with a pcv and its fine for me.
Read my thread here: The Evolution of my Turbo Lexus from NA-Supercharged-Twin Turbo-Massive Single
Please leave your comments.
My mate took his pipe off his pcv and smoke started 5 mins later coming from the dip stick and breather so im assuming and hoping ive not got ridiculous blow by
Jimbob-T-Lex
07-04-2020, 09:23 AM #838i wasnt either but this is what rid the gases and blow by so the vapour are burnt this then stops my smoke coming from the rocker and dipstick but as its flowing so much from the pcv its making my a/f ridiculously rich and my vacuum drops like crazy
My mate took his pipe off his pcv and smoke started 5 mins later coming from the dip stick and breather so im assuming and hoping ive not got ridiculous blow by
I was still getting the stall when i boost till waste gate opens but if i change when wastegate opens i can boost harder and go faster till it opens again then stalls again when wastegate opens but got a vid ill post up so you can see where im at she still might make JAPPOWER lol
Jimbob-T-Lex
08-04-2020, 11:26 AM #839Well all of a sudden today she started to play ball lol i been out driving and all still had a random misfire on 4,5 and 6 but when i looked at the fuel trims bank one was sat at +19.5 constant and bank 2 was changing wierd as im running both off one lambda sensor lol
I was still getting the stall when i boost till waste gate opens but if i change when wastegate opens i can boost harder and go faster till it opens again then stalls again when wastegate opens but got a vid ill post up so you can see where im at she still might make JAPPOWER lol
Read my thread here: The Evolution of my Turbo Lexus from NA-Supercharged-Twin Turbo-Massive Single
Please leave your comments.
Sparkystav
08-04-2020, 01:00 PM #840Great news mate!
Read my thread here: The Evolution of my Turbo Lexus from NA-Supercharged-Twin Turbo-Massive Single
Please leave your comments.
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