MIDN1T3
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Re: Re-routing AC Idle up vacuum hose Gen 3
2014/01/20 11:34:25
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Thanks for all the replies guys. However, I think pictures will clear up exactly what I'm asking...because I'm still confused lol. So, I'll start right back from the beginning :) This is my old Gen 3 hotpipe with the vacuum nipple that goes to the AC idle up sensor.  I no longer have this hotpipe because I put in a new intercooler set up.  Now here is the AC idle up sensor with the wires on top and the vacuum hoses on the bottom.  The vacuum hose on the left goes to the bottom of the intake manifold AFTER the throttle body.  The vacuum hose on the right (used to go the hotpipe) is here...  Ok - so I left this above vacuum hose unplugged, and it let out boost and hence I don't hit full boost. So my question is, since the Gen 2 does not have this nipple...  yet has the exact same AC idle up sensor with two vacuum hoses, where can I re-route mine easily? (Also, by the sounds of it, Artymr2 Gen 3 does not have the nipple either, so where does yours go mate?) Thanks Dasic1 for your suggestions, but I don't think it can go before the turbo as I would still lose boost. And my new intercooler set up makes it hard to put a new nipple in between the turbo and the throttle butterfly.
1990 SW20 MR2 N/A with 1994 Gen 3 GTS 3S-GTE swap.
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track_mr2
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Re: Re-routing AC Idle up vacuum hose Gen 3
2014/01/20 12:01:05
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Hi. I don't think you should be losing boost. The idle up for the AC is supposed to be a one way valve to suck in air.
It controls the amount of air bypassing the throttle body, thus controls your idle and has the ability to raise your idle speed when the AC is on. It shouldn't be opening all the time. Also its such a small hose that even if it did leek boost it wouldn't effect you making full boost. How many PSI are you running? Like if your only running 16psi or less the gen 3 tirbo will easily spin fast enough to hit that boost with the pipe disconnected. Try blocking off that pipe and seeing if you hit full boost then. Anyway as for routing it after the turbo, you will probably be best to have that metal BOV adapter (pipe joiner) modified to take a fitting you can plug the hose into. My Gen 3 has a fitting just under the BOV after the turbo.
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Senor_2
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Re: Re-routing AC Idle up vacuum hose Gen 3
2014/01/20 12:04:04
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I would just make a new fitting somewhere in a similar position, after turbo, pre throttle body. Edit: what track_mr2 said, drill and tap a fitting on the BOV joiner pipe
post edited by Senor_2 - 2014/01/20 12:08:50
A man in Dandism ========================== SW20 Midship Runabout
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MIDN1T3
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Re: Re-routing AC Idle up vacuum hose Gen 3
2014/01/20 12:10:57
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track_mr2 - Yep, I plugged it up and it hits full boost. It will even let air out by just revving the engine, so maybe there is something wrong with that one-way valve?
Senor_2 - Yep, I did initially look at getting a nipple welded onto the BOV metal joiner, just thought there might be an easier way haha.
1990 SW20 MR2 N/A with 1994 Gen 3 GTS 3S-GTE swap.
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dasic1
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Re: Re-routing AC Idle up vacuum hose Gen 3
2014/01/20 12:39:00
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Yeah sounds like something is wrong with the valve
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Carmikey
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Re: Re-routing AC Idle up vacuum hose Gen 3
2014/01/20 13:47:51
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^^MIDNIT3 - there is an easy way to check the correct valve operation. I saw it recently in the BGB. I will see if I can find it again.
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MIDN1T3
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Re: Re-routing AC Idle up vacuum hose Gen 3
2014/01/20 14:04:40
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Carmikey - thanks mate, appreciate it.
Also, I've pm'd you.
1990 SW20 MR2 N/A with 1994 Gen 3 GTS 3S-GTE swap.
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artymr2
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Re: Re-routing AC Idle up vacuum hose Gen 3
2014/01/20 16:07:51
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When I next see our car I will see where this hose goes and let you know.
Cheers
Black SW20 GT Turbo T-top 
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Senor_2
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Re: Re-routing AC Idle up vacuum hose Gen 3
2014/01/20 16:17:51
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This should be what carmikey was referring to: 
A man in Dandism ========================== SW20 Midship Runabout
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MIDN1T3
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Re: Re-routing AC Idle up vacuum hose Gen 3
2014/01/20 21:36:48
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Awesome, thanks guys. Really appreciate it.
I'll test the operation of it tomorrow.
Arty, get a chance to look at yours?
1990 SW20 MR2 N/A with 1994 Gen 3 GTS 3S-GTE swap.
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cogs
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MIDN1T3
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Re: Re-routing AC Idle up vacuum hose Gen 3
2014/01/23 11:30:29
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Thanks Cogs. (I'm thinking about just getting a nipple welded onto the BOV joiner pipe.)
Ok. So I tested the AC idle up VSV using the above method from the BGB, and it works fine. I also had a spare Gen 2 VSV that I tested as well and it worked fine as well. So the VSV is not faulty.
Then I tested the sensor plug using a circuit tester, and there is power there when the AC is off, but no power when the AC is on. Yep, it working in reverse!
After looking at a few wiring diagrams, it gets the signal from the AC Amplifier and then I remembered when I got the AC fixed many years ago, they said there was something faulty with the Amplifier which they 'fixed'. Yay. I have a suspicion they either wired in up incorrectly or put in a generic amplifier.
So...where to from here? And to think I just wanted to re-route a vacuum hose!
For now, I'll leave the VSV sensor unplugged which mean no air being let in or out, and work myself up into figuring out where the AC amp is located and how I'm going to fix it.
1990 SW20 MR2 N/A with 1994 Gen 3 GTS 3S-GTE swap.
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Mrskylighter
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Re: Re-routing AC Idle up vacuum hose Gen 3
2014/01/23 11:51:06
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Is your car an early model sw20 with a gen 3 conversion? If it is there is a work around you need to do to get the ac idle working the right way round.
I experienced this myself with my old 1990 running a later model power fc.
I installed a relay next to the ecu to switch the ac signal going into the stock ecu.
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Mrskylighter
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Re: Re-routing AC Idle up vacuum hose Gen 3
2014/01/23 11:54:41
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What people experience when they have this issue is that the car seems to idle low or struggles a bit with the ac on. With the ac off the car idles higher than normal.
Is that what's happening to you?
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MIDN1T3
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Re: Re-routing AC Idle up vacuum hose Gen 3
2014/01/23 14:19:20
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Hey Nick, my car was a 1990 NA ADM model before I put the Gen 3 in.
Yep, that's exactly right... Idles high without AC then struggles with AC on. I fixed this (kinda) by increasing the idle slightly, way back when I first did the conversion (had a lot less knowledge about the car back then, just thought the load of the AC compressor made the engine idle lower).
Very interested in how you fixed it!
1990 SW20 MR2 N/A with 1994 Gen 3 GTS 3S-GTE swap.
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