My AEM Analog 35psi boost gauge is reading all wrong. It is very slow to react and it is pegging out at 17psi in 3rd gear, and maxes at 19-20 in 6th gear. The vacuum is maxing at about 14-16inHG also. The car is tuned for 27psi. My stock MR boost gauge is also reading just fine. Could my vacuum line be the wrong diameter and causing it to be thrown off? Could I have too much vacuum line between the boost signal and MAP sensor? (I have the sensor mounted inside the car for easy removal)



I saw this review by MAP of these gauges online (mine don't respond nearly this well, this video is not my car):
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Does anyone have these? If so, where did you get your boost source? Did you use the barb fitting on the MAP sensor, or tap into something for the sensor?

I don't have any boost leaks, no kinks in the line that I know of, and I waited for the little opening ceremony/calibration part also. WTF?





PROBLEM RESOLVED EDIT: Talked to AEM about this and we figured out that they had sent me the wrong sensor somehow. If your 35psi AEM boost gauge is doing something similar, make sure you have the "50 psia" sensor and not the "75 psia" sensor, the 75 psia is for the 50 psi boost gauge.

 

Anyone? The only thing I can think of is that I may have received the wrong sensor with my gauge. I will be checking again for a kinked vacuum line and calling AEM tech support when I get a chance.

 

I have both gauges and they work great as long as you let it zero out first and don't crank to long (I need to change to a keyed source that doesn't turn off when you crank).

For vac/boost source, I t'd the line to the fuel pressure regulator. If you have a low reading on both vac and boost and a slow response, I would definitely guess a kink in the line. Did you mount the sensor in the engine bay or run a vac line to the cabin?

 

When I installed the AEM digital boost gauge, it was acting weird also. Low readings, unresponsive, etc. I already had the MR gauges, so I had simply shortened the vacuum/boost hose that went to the original boost gauge and connected it to the AEM sensor under the hood. When I was checking for a source of the problem, I noticed that the vacuum hose looked like it might be crimped at the T-fitting near the fuel pressure regulator. IMO, there's very little room to install the T-fitting without crimping the vacuum line. I removed the T, and replaced it with a Y-fitting using the tail of the Y for the line going to the boost sensor. That resulted in much less bending of the rubber line.

I also discovered that there is a tiny restrictor pill in the factory vacuum line going to the original boost gauge. I've never seen any other posts about this pill, but its there in the factory line. I think that the orifice in the pill is incredibly small when compared to the size of the nipple on the AEM boost sensor, so I replaced the section of the original hose containing the pill with a new vacuum line. After that, the new boost gauge worked perfectly ever after. I'll never know if the problem was due to a crimp, the pill, or both.

 

I T'd into the same line that my MR boost gauge is, about 2" away from there the stock T is. I ran a vacuum line through the hole behind the glove box, behind the center console, and tied it up above where my feet would be while driving. Then the sensor wires run up to the A pillar pod. I did this so it would be easy to replace.


I have been talking with AEM tech support, they want me to test the sensor, they think it may be bad.