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Discussion Starter · #1 ·
Well, after just over a year my AEM boost gauge stopped working. I searched around and most say the sending unit is bad. I called AEM and they offered to take a look at it if I send it in. I decided to just get a new sending unit from MAPerformace but I have not been able to install it yet.

The gauge has always read 1-3psi high since first install. Recently it started reading progressively lower, for a few days, it would read vacuum correctly but then stop at zero when boosting. I tossed the old laptop in the car and I am in fact boosting still to 27psi. Now it is stuck at -18/-20inhg and never moves at all.

I couldn't find any information specifically on this behavior, so here it is. I will post up if the sensor fixes it or whether it is the gauge.
 

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Oddly enough, my gauge is reverse, it reads boost no problem, but it has never read vacuum, it always sits at 0.
 

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Now that I think about it, I had to splice the boost gauge wires and extend them to reach all the way to my cabin. I wonder if one wire indicates boost and another vacuum and as a result I don't get a vacuum reading due to some issue with the extension of the wires.

I apologize for the digression, for a moment there I thought it was relevant to your problem, but I see now that it really isn't! :tumbleweed:
 

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I just installed an aem boost guage a couple weeks ago... No probs to report *yet*, other than it seems a bit slow to respond...
So aem wouldnt warranty its guage, or u just didnt feel like waiting to see if they'll replace it?
 

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I hate AEM, I have 5 analog series gauges and they all have some type of problem. One changes colors randomly (like a Christmas tree). Otheres have hairline cracks on the plastic cap on the dial. The boost gauge needs to "calibrate" for a second before the ignition turns on, and if you don't pause it gives you a funky reading.

My trans temp sensor is so noisy it drowns out the dash rattles, which as we all know is loud as hell.
 

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Check what psi the gauge it is rated to. It needs to be one that is 50psi. Mine did the same thing as the OP and it was only rated to 35psi. I got mine used and didn't know better.
 

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I have a digital AEM Boost and it drives me crazy as well. The most boost it ever reads is about 12 which is way off. Need to try a new sending unit i guess. I think my gauge is only 35 PSI. That should be high enough right? Not sure why you mention a 50 PSI, post back and let me know.
 

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There are 2 things. The gauge only needs to be 35, but the sending unit needs to be a 50psi unit for a 35 psi display gauge to read properly.

Don't ask me why as I don't know the answer. But I have verified this with AEM to be sure as they dignosed my problem when my display guage would never read over 0psi even though I was truely boosting to 25.
 

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Discussion Starter · #9 ·
Check what psi the gauge it is rated to. It needs to be one that is 50psi. Mine did the same thing as the OP and it was only rated to 35psi. I got mine used and didn't know better.
Mine has worked fine for over a year and it is already the 50psi unit.
 

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You can hook a volt meter up the the leads coming from the sending unit and check the voltage at different boost levels. It was the black and green wires on my AEM analog gauge, not sure if it is any different for the digital.

Pretty easy test to do with another person in the car reading the volt meter and will tell you if the sending unit is working or not.
 

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Sorry for bumping an old thread but I'm having this same issue with my digital aem boost 35psi boost gauge. I just bought the gauge and it was used for 5 months.

After following the how-to. I started the car and the gauge did it's thing and settled at ~22 vacuum. I went for a drive and went well into boost but the gauge never read passed 0.

My question is what voltage should I expect for 21 psi boost??
Is 5v = 35psi?
So 21psi should be around 4.3ish
Or is one wire for boost and one wire for vacuum

Any help would be great
 
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