Mysterious Hissing device 1G-GTE

[andyroo]

Hi,

I have no idea what the heck this thing is, it makes a light hissing noise sometimes* while the engine is running, it also lets a hissing noise out when you turn off the ignition, I stalled awhile back and when I went to turn the ignition off (engine not running) it still made the hiss noise when I moved the key back from ON to ACC..
My mechanic thinks it might be a factory boost controller, but it was a bit of a stab in the dark.. heres some pics, any info will earn a gold star.





Thanks, Andrew

[PlacentaJuan]

its a vacuum/pressure solenoid.

my 2jz has lots of them to actuate the sequential turbo actuators.

when powered it will allow air (or vacuum) to flow through it.

if one side is pressurised and the thing is leaking you will probably hear it hissing once the ambient noise is low enough.

if its loud there must be a pretty big leak.

actualyl also i think sometimes they just allow pressure to vent to atmosphere when atcuated, but i dont know much about the 1g.

edit: looks like you have an aftermarket plug on it so maybe it IS set up as a boost controller.

[andyroo]

I dont think its leaking, you can only hear it when the revs drop back to idle, the strange thing is it only sometimes makes the noise at idle.. If I install a boost controller will this interfere with it?

[oldcorollas]

is that black cylindrical thing a filter or a noise suppressor?
i agree with PJ, they are either to let air/vacuum through, let air in (idle up etc) or let air out (boost controller), but could be any of them. but it is typically an on/off thing, not a controller.

where do the lines run to?

if you were keen, you could pull it out and check what lines connect to what when the solenoid is energised.

i assume you've checked the diagrams for your engine?

[thechuckster]

it is probably for TVIS control - the charcoal cannister system vent are sometimes controlled by VSVs but usually with no venting capability.

It switches vacuum and when not enabled, one of the ports will vent (suck actually) to the atmo via the black thing.

[PlacentaJuan]

yes but i still think it does not look like a stock install; more like someoen has installed it for something.

do turbo engines have tvis? i have no idea but i thought it was for n/a engines only.

also the position with the vac lines rubbing against the resiviour, cable ties over the lines and a new electrical plug all points to something non-standard.

you can well use these parts for a cheap boost controller, trace the lines back and tell us where they go.

[JustCallMeOrlando]

I'll tell you right now, it doesn't look like anything factory 1GGTE. The only VSV I've seen on one of them is for the TVIS but that's under the inlet manifold.

[Hydra]

I think that'll be more to do with the chassis, possibly to do with the emissions gear or automatic aircond. I have something similar in the same sorta location.

[Rcubed]

it looks similar and [from your description] makes the same noises that the a/c idle up that came with my 2T-GEU.
i suspect on yours the black round thing houses an air filter and that you can turn it to vary the intake volume.
what do the two vacuum lines go to?
on some engines there are off idle solenoids like this to reduce the rate of RPM drop between gears. Craig Deane [ddeane] may know as he even has the vacuum assisted clutch.

[YLD-16L]

The 4AGZE had 2 of those, the black cylindrical thing is an over engineered plug. The three barbs are in/out then a normally open barb and a normally closed barb, the black cylindrical thing just blanks off the one not in use.

As has been said 3 or 4 times already, trace where the the vac lines run to and you'll identify exactly what it is doing

Simple.

[andyroo]

Here is where the lines run to, only one hose #3 runs into this; note that #2 line is diverted in a t section, the top line runs up into the dash, the later pictures show where the lower line runs.





#2 line runs into this canister below the intake manifold;


And then back out up into the manifold, (in the center of frame, or the farthest to the right)

[thechuckster]

vacuum source for climate control and heater control

[BradW]

What ever this is attached to is what the vsv is controlling. This is a vacumm controlled actuator and will have a shaft coming out of it which will be attached to something. Looking at that pic, maybe heater tap?

[thechuckster]

that vacuum-controlled actuator is the hot water tap - unlike a traditional heater/AC setup - hot water supply to the internal heater is either on or off and the climate control mixes air going thru or around the heater core.

[Hydra]

Like he said

I had problems getting hot air outta my XX after 1JZ-ing it, had the vacuum line hooked up wrong.