[tmac26]

hi all, today i took off my recirc pipe from the wrx dump valve, i blocked the recirc pipe and took it for a blast to hear the noise, it does actually work BUT....... when i come to a halt the engine idles at about 200 revs and wants to cut out, so i took it straight back and put it back on, my question is, would a bov have the same effect of what happened when taking the recirc pipe off, or would the car run idle at higher revs, thanks

 

[tmac26]

your recirc valve is a bov. it's just the air that is purged is recirculated back into the system.

the reason you are having stumbling issues is because you are losing air that has already been metered and calculated for by the mafs. the ecu determines the amount of fuel based on that metered air. by venting to atmosphere after the mafs you are losing some of that metered air causing a rich situation which you see with your stumbling issues.

venting to atmosphere is just a sound...is it really that important vs. having the car run properly like it's supposed to?

yea iv been doin alot of readin on this subject, but should it run so bad at idle, could this be a sign that the dump valve is leakin?

 

[tmac26]

i did put straight back on, but i tried what stealth said today, about covering the bov end, that did help, i also noticed that the dumpvalve was open on idle and when i put my hand infront of it i can feel the air pushing out, only when i rev the engine quite hard thats when the dumpvalve shuts and when i release it opens, but arnt they supposed to stay shut until i let of the accelerator, also it runs fine when the recirc pipe is connected it only runs crap when the pipe is off.

 

[tmac26]

That's why I didn't understand why it was struggling at idle.

so u rekon that the dump valves fooked then?