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what sensor is the one that is mounted to the factory air box. looks like and idle air control motor, but i thought i saw one on my throtle body. not sure what it is, but i sure dont have it.

VAF or Volume Air Flow Sensor, sometimes mistaken as a MAF or Mass Air Flow Sensor. Tells the computer how much air is coming in through the intake, and helps it calculate the appropriate amount of fuel to inject to get the correct air/fuel ratio. If you don't have one, your car probably runs rather poorly, but did the previous owner have any other goodies installed?

is it oin the intake tract? then its the VAF, if its on the side its the fuel pressure regulator solinoid. that ahs 2 vacumb lines on it.

tehbrookzorz wrote:VAF or Volume Air Flow Sensor, sometimes mistaken as a MAF or Mass Air Flow Sensor. Tells the computer how much air is coming in through the intake, and helps it calculate the appropriate amount of fuel to inject to get the correct air/fuel ratio. If you don't have one, your car probably runs rather poorly, but did the previous owner have any other goodies installed?

MAF => Hotwire
VAF => Trapdoor

And I've never seen a car run at all without one plugged in (unless modded of course)

Yeah, I don't think he's talking about the VAF. You can't run without it. I think he's referring to the little sensor assembly that mounts onto the side of the air filter box and has some thin vacuum lines going into it. I think most people who do CAI take it off. I don't know what it does.

You can, but you shouldn't.

Whisper wrote:Yeah, I don't think he's talking about the VAF. You can't run without it. I think he's referring to the little sensor assembly that mounts onto the side of the air filter box and has some thin vacuum lines going into it. I think most people who do CAI take it off. I don't know what it does.

yeah thats the one im talking about. i know what the VAF is.

is that lil one on the air filter box, i saw it on mx-3 at a junkyard, thought it was odd cuz it had a mitsubishi emblem on it

Yes, mine has a Mitsubishi symbol on it too. MX-3 uses a couple of parts made by Mitsubishi, and I think other automakers as well.

ok.. loll, but what is it for!?

alright i found out what it is after looking for 30 min in the online shop manual, is a PRC valve (presure regulator control), well how the hell can u drive ur car without it!?

the only time my mx-3 ran, it would just idle if u try to accelerator it'd just cut off, and then i checked the engine code and it told me it was that PRC valve, kinda make sense now. although, the klze i bought, the vacuum line is connected to a plug on the throtle body i believe, instead of that valve. but the computer doesnt know that , dont know if i make sense lol.

Oh, that's what autozam said, then.

Yeah, I don't know wtf. I wonder if you can get a junky one.

hehe just found out on chiltons manual that PRC valve is only equipped on californian emission models, dont know if its true though.

I've got one.

I;ve got one too, but I have 3 vac lines going to it but only 2 hooked up and the third is plugged anyone else.

when i first put a CAI in my car i removed that sensor and blocked the lines , but it will make you run rich as hell, i set it back up and runs better and has better fuel milage