I installed the AEM boost gauge couple days ago and had a ques. about it. When I step on the gas it shows about 6-10 psi but as soon as i let go it'll show 24-26psi. Is this normal, because the gauge would show normal psi (24-26) when I'm steeping on the gas, not when i let go of it. Also, under hard driving the gauge will show 0 psi, but as soon as i let go of the throttle it shows 24psi again.
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wrong vacuum line

also know the difference when it is in KPA vs BOOST

 

what he said, you tapped the wrong line.

 

I checked like 3 times and I followed the diy instructions pretty well. Also, I think it would constantly show 0 if I did tap the wrong line. I think, there's a calibration problem which is well know issue with aem

 

It should show constant zeron regardless. it should show the vacuum, then go in to boost.

I havent heard or seen a calibration problem. I use their boost controller on my 9 second mustang and installed/tune on other case using aem stuff.. Good bang for the buck other than meth kits.

 

Dumb question but do you realize there is vac and boost on a boost gauge? Not trying to insult you but I had to be asked.

I am starting to question the accuracy of this gauge as well but I will decide after i do a boost leak test.

 

i have the gauge, and its perfectly accurate. Can you take a pic of where you tapped for it? also, where did you run the line into the car? through the wheel well or did you drill through the firewall?

 

the only negative thing about the gauge is it doesn't have a negative sign when it reading vacuum...that what 24-26 inches of vacuum you see when you let go of the throttle.

 

thx for the input guys, I

 

Thanks for the input guys, I had it run from the wheel well. I installed it again and the reading was off again. I found no sign of boost leak or pinching in the line. And, yes I know the difference between the boost vs vacuum reading. I bought it used from a friend and am planning to return it to him. I will either buy new aem or new defi soon!

 

If the gauge doesn't read "0" with the ignition on but the car not running then you have either a bad gauge or sensor. Replace them both. Happened to me.

 

Evo x here mine is tapped to the blow off on a t…..
I read 20 ish at idle and when I get on it it reads lower number up to 0
would this be normal? Or is sensor or gauge bad?
I have a leak on my downpipe could this be the reason?

 

Boost gauge needs to go to the ENGINE side of the throttle body for proper reading. There is a port on the intake manifold that you need to T into there. Anywhere else is wrong.

 

Correct but my other question is so I read o when it’s off when it’s idle I read anywhere from 20ish and when I get on it reads lower numbers up to 0 is this normal?

 

20 what? I will assume you are talking -20 in-hg which would be normal. the engine is pulling a vacuum on the intake manifold at idle and until the turbo is creating enough pressure to cancel out the vacuum. Then boost pressure(psi) is just the positive pressure being created.

0 with the engine off is also correct as there is no vacuum or positive pressure with nothing moving.