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Scion tC 1G Forced Induction Turbo and supercharger applications...

Boost Gauge

Old Nov 4, 2011 | 03:46 AM
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Default Boost Gauge

So I have a GlowShift boost gauge for my supercharger.
All things are working well. When I'm at idle (~700rpm) the boost gauge freaks out and bounces like crazy between 20vac and 10vac. Is that just the fluctuation in intake air happening one piston at a time and the gauge is picking up each flux?
Old Nov 4, 2011 | 09:25 AM
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i know a few ppl that have the same issue with the boost gauge,on idle the needle is fine,but once it gets to 20 to 10 the needle bounces like crazy
Old Nov 4, 2011 | 03:32 PM
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idle doesnt change at all? if it is i'd say maybe you should look at your vac lines. maybe the nylon line has cracked.
Old Nov 4, 2011 | 03:32 PM
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Check for leaks.
Old Nov 4, 2011 | 06:07 PM
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It's like when I come to a stop light, the car takes a few seconds to drop to idle rpm's (~700rpm). Then the boost gauge starts bouncing. If I rev up it stops. While i'm just driving in 5th gear on the highway it doesn't do it. Just at idle.

The only thing I have changed is my intake length. It used to be a full length CAI mated to the S/C but I just made it a shorty directly off the S/C.

It is all going to get changed soon with my W/A intercooler, custom piping, intake etc.

Is there a better way to do VAC/Boost lines other then the rubber tubing?
Old Nov 4, 2011 | 06:10 PM
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well not with the nylon tubing kind. it kind of sounds like a vac leak my friend. it's a mechanical gauge right? if it's electronic then the gauge or sender is defective. if the gauge is mechanical then it's a leak somewhere. that crappy nylon line can kink or crack really easy.
Old Nov 4, 2011 | 08:43 PM
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I've ran into this problem before. You probably kinked thr nylon vacuum line somewhere when you installed it. It sounds like exactly what your describing. Either it's that. Or you have a vacuum leak somewhere
Old Nov 4, 2011 | 08:47 PM
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If you can't find a leak I'm sure the gauge may be broken. I've seem more then enough of the glow shift gauges break for no reason. Theyre not the beat quality.
Old Nov 5, 2011 | 03:02 AM
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Did you install the restricted t fitting?
Old Nov 5, 2011 | 06:23 AM
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Yes, there are two T fittings, the one that was installed by Toyota for the BPV and the other for my gauge. I will be digging under the hood tomorrow to solve this. Might also look into a digital (boost only) gauge.
Old Nov 6, 2011 | 04:50 PM
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Yea man I highly recommend getting a electronic one I've had way fewer problems with my defi then I did my old mechanical gauges.

Sent from my ADR6300 using Tapatalk
Old Nov 7, 2011 | 12:24 AM
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if u have it hooked inline with ur evap solenoid it will do it..
Old Nov 7, 2011 | 11:05 PM
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http://www.flickr.com/photos/p3t3r5on/6324237512/

So what you're saying is this setup might be the problem?
Old Nov 8, 2011 | 12:42 AM
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buy a vac block
Old Nov 8, 2011 | 03:40 AM
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awesome... thank you


... TO DEZOD!
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