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Discussion Starter #1
I just installed an Autometer boost guage on my SC. With the engine off, the guage is at 5 vacuum. Once I start it up it goes down to around 20 vacuum, and when I step on the gas it goes to about 3 vacuum. It is never reading a boost level, just vacuum. It seems to be moving correctly when I step on the gas it stays at about 3 vacuum, and when I let off the gas or let it idle it goes down to around 20 vacuum. But shouldn't it be reading 8 psi, instead of 2 vacuum?
 

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Don't know about the vacuum readings, the gauge may just need calibration. If you tapped into the throttle body or into the intake before the SC the gauge will never see pressure. I would think a good tapping point would be the line on the intake manifold that feeds the fuel pressure regulator. I tapped into the intake hose right before it dumps into the intake manifold.
 

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Discussion Starter #3
Could anyone with a boost guage on their SC post pictures of where the T-eed their boost guage hose in?

I used this diagram for installing mine. I found this in an old thread that Kirk posted:


I just realized that i didn't cap off the vacuum port that it says to in that picture. Could that be why I'm getting only vacuum readings and now boost psi?
 

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Discussion Starter #4
Anyone?
 

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That picture is for the ABV mod. Not capping that hose should not effect boost bauge readings since the TB is on the inlet side of the SC and won't see pressure, only vacuum. It is causing a vacuum leak though if it's not capped.

Tap you boost gauge into where it says"Tee into here" as I believe that line comes off of the intake manifold.
 

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Discussion Starter #6
I tapped it into the online line that came out of the round canister which should be the Air bypass valve but I don't think it went to the intake manifold....

My 4AGZE is JDM so it may be a little different...
 

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no its not different...tap it inline where the ABV Tee off is
 

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MR2Fast2Catch said:
Could anyone with a boost guage on their SC post pictures of where the T-eed their boost guage hose in?

I have a JDM 4AGZE & my autometer gauge works perfectly.


Pic
Another Pic
 

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Discussion Starter #9 (Edited)
Thanks for the pic Sandra, I'll try to look for that in the engine bay.

EDIT: I think the previous owner could have mismatched some vacuum hoses when he installed the engine. The one vacuum hose that come off of the ABV goes to a vacuum port that is left open on the diagram above. And the hose that goes from the intake manifold to the VSV (which then goes to the fuel pressure regulator) does not meet up with the ABV like it should in the diagram. Hmmm....
 

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Discussion Starter #10
Alright I think I got it working, kinda. I had to use 2 T's since the vacuum hoses were installed incorrectly. Now I am getting about 20 vacuum when just coasting or idling, and when I floor it it goes up to 3-4 psi of boost. That's a good sign that I'm finally getting a boost reading. But shouldn't it be at 8 psi? I am running a stock JDM 4AGZE. Maybe there is a vacuum leak somewhere or could my engine be running with low boost because of a really dirty K&N cone filter? :D
 

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boost gauges tend to drift on their calibration. If it is 5 in/hg with the engine off, you need to add about 5 psi to your other readings. So 8-9 PSI on boost and 15 in/hg vacuum at idle, which is correct.
 

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Discussion Starter #12
Can I change the calibration of the guage so I don't have to do the math every time I look at it? LOL. Or is it just the way the guage is made. If that's the case then I'll probably sell my guage and find another one that is more accurate...
 
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