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Discussion Starter #1
ok. so i bought a 3" mandrel bent pipe for my intake. its in the shape of a "U" so i have to cut it and stuff. i was talking to one of my co-workers at toyota (one of the technicians) and he said i dont have to worry about making fittings for the 2 vacuume hoses that attach to the intake pipe. he said that all those 2 hoses are for is for 2 vaccum switches. he said one switch makes it easier to steer at idle, and the other vacuum switch brings your idle up when you turn your headlights on. does anyone know if thats what those are really for? this guy was just an apprentice so i wanna check witha u guys first thx.
 

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Discussion Starter #3
alright thanks! thats all i needed to know :)
 

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The smaller hose is for power steering, while the larger hose is for the idle air valve. Which dealership do you work at, so we know not to take our cars there!
-Aaron
 

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Discussion Starter #5
lol i work at valley toyota in chilliwack, BC. this guy was just an apprentice who probably dosnt even have much experience with the 5MGE. i know hes really familiar with the mid 80's corrolas tho.
 

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Uhh, maybe I missed something but it seems to me that he was dead on accurate. One hose is for power steering, as Aaron said, and what it does is up the pressure on the pump so it's easier to steer. Sound familiar?

The large hose is for the idle air valve, so Aaron says, and guess what it does? It lets more air through to raise the idle when it senses a larger load on the engine. When you turn on your headlights it increases draw and needs more output from the alternator to keep charging the battery so it makes the alternator work harder, in turn puttin a larger load on the engine. Seems to me Aaron and that tech are saying the same thing.

The engine will run fine if you take the power steering one out but I'd imagine that you would want to put a filter on the idle air control valve intake since it will be sucking non filtered air if you get rid of that line. Try it, just unplug them one at a time and cap the hole with your finger, it's easy. If it runs then get rid of them, if it dies then keep them. Simple as that.
 

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RWDCelicadude said:
One hose is for power steering, as Aaron said, and what it does is up the pressure on the pump so it's easier to steer.
Close, but not quite. What it actually does is increase the idle speed when the line pressure in the P/S reaches a certain threshold. This usually happens when you're at full lock, and the extra load can be enough to stall the engine. The purpose of the valve is to prevent the engine from stalling, not increase the P/S line pressure.
 

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That's interesting because my old car didn't have it and I took it off my new one and neither has any problems with stalling at full lock. Maybe the supras have a beefier PS pump than the celicas and it draws down the engine more?
 

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Well I will tell you this I'm no mechanic but when I first installed my RC intake pipe my car died a few times right after instalation on the way home. I opened the hood and noticed that the larger of the two hoses came disconected.... I reconected that hose and the car quit dying on me.

I would say that you need them

HTH

will
 

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supra_toy said:
Well I will tell you this I'm no mechanic but when I first installed my RC intake pipe my car died a few times right after instalation on the way home. I opened the hood and noticed that the larger of the two hoses came disconected.... I reconected that hose and the car quit dying on me.

I would say that you need them

HTH

will
It's not so much you need the hoses connected but that you cant have an open hole sucking in the extra air after the AFM. Big vacuum leak in your intake pipe caused your problem - not the lack of vacuum to the hose not connected. :!:
 

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Here is a page with some good information about the ISCV and Toyota vehicles: http://www.autoshop101.com/forms/h60.pdf It appears that the type of ISCV can vary from engine to engine. It does mention that some of the ISCVs are affected by a number of input signals, such as A/C activation, low battery current, etc. I could not make total sense of the information as it pertains to the ISCV on the 5mge. Later!
-Aaron
 

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The large hose supplies ALL of the air to the ISCV at idle where
the TP is completely closed per autoshop101. If u don't have the
hose then at idle no air will pass thru the afm and the ecu will
stop the engine cause the afm signal's telling the ecu there'sno air.

StanS
 

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Discussion Starter #13
Aaron, in that website you posted about all the that info about the ISCV. what are they talking about where it says ECM? i see its come kind of sensor. right now my ISCV is not working. when i fire up my car in the morning sometimes it stalls but if it dosnt stall it just sits there at 500 rpm. i replaced the actual valve and when i put it in and started my car up it just stayed at 2300 rpm for about 5 mins. so i guess the new ISCV i put in was in the open position when i put it in. after letting it idle at 2300 rpm for 5 mins i shut the engine off and fired it back up and its never gone over 500 rpm since i restarted the engine. so i'm assuming that my ISCV isnt getting a signal. do you know where the problem could be?
 

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actually, you can technically leave both open, the power steering one isnt gonna affect anything really. may be a little more dificult to steer at some times but doubt it. just make sure the pipe from the afm to tb has no leaks. also, the isc hose can be plugged or filtered. its best to have it hooked to the intake pipe but not necessary. if you plug that hose you have to readjust the idle screw on your tb. it may still be plugged. if so youll have to drill it out. ive seen many 7mgtes that disconnect the isc valve when it gets clogged and just readjust the idle. it will work but not recomended. your idle wont pick up with low voltage and the a/c like its supposed to anymore. so you need at least one port for the big hose.
william
 

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smaller hose. disconnect and plug if you aren't going to use it. engine MAY stall at full lock but prolly not.

the big pipe. HAS to be plugged into the intake pipe after the afm. cannot be filtered. want to see how it would run with them both bypassed? dissconnect them from the intake pipe that is there and plug the intake pipe connections and leave the pipes int he open. try to start it and have it idle. it won't. it might sputter for a few seconds and will work if you press the gas but it will never idle...ever.
 

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actually it WILL idle but you have to adjust the bypass screw in the tb to allow enough air to bypass the tb.
william
 

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it won't idle if the afm isn't registering any air passing by it. ever accedentally forgotten to connect the afm or run the car w/out it? it sputters at about 200 and does a seconds or so later. what your talking about would be okay but on cold days you'll have to manually hold the pedal down to keep it from dying if you adjust it to idle at factory specs. in other words no computer controlled idle and no fastidle. a/c idle up won't work anymore and the electrical load idle up won't work either.

basicly you end up with a crappy low idle with a/c or a 1400 rpm idle w/out a/c.
 

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Rabid Chimp

Know what you are talking about before you jump in and say anything. Perhaps honor prices listed on this website also when you visit. I have a homemade kit on my car and no lines are hooked up rather teed off and my car run's fine, not to mention I have no O2 sensor. Restoring car and coming along. Will list pic's as I get closer to finish. :evil: :evil: :evil:
 

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ok, since the isc valve hose will be plugged, all the air will have to pass through the afm. the car WILL idle with the isc valve disconnected and plugged. you just have to adjust the idle screw on the tb. if you had read my first post i said the idle wouldnt raise that way and would be best if the hose was connected, but the car will run and idle with out it if its plugged and you adjust it right.
william
 

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I say if the factory put them there....they are there for a reason..keep it that way....and yes 1 is to the p/s and 1 is to the iscv..that has too be there..itll stall....plus it aint hard to weld 2 lil pipes ...id say just do it...why would you want to leave stuff undone..??
 
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