I installed a new AEM electronic boost gauge this weekend, which was the first time I have ever installed a boost gauge and I suspect I may have done something stupid. It is reading as I would expect during idle (slight vacuum) and cruise (~0), but is reading high under acceleration.

I had read the various threads I could find on how to connect the sensor and have a picture showing the vacuum line T below (just above the throttle body). Can anyone confirm that I have tapped the correct vacuum line?

The gauge is reading up to 32 psi by 3500rpm and is staying there until ~5Krpm where it drops slightly. The car is stock except for running a Perrin stage 1 map with peak boost targets around 25psi.

Any suggestions would be appreciated.

Thanks,
Jim

 

i think u tee'd it at the right spot if it is the one that goes to the BOV. are you over boosting ? check the lines make sure they're not blocked and your wiring connections to the gauge.

 

Thank you for the response. It is the line that goes to the BOV. I have double checked the wires to the gauge and didn't see any issue with the vacuum lines, but will do some more investigating tonight. Hopefully not overboosting that much...hadn't even considered that the reading might be accurate.

 

Does your gauge turn off momentarily when you crank the car over? If so, the problem is where your getting your switched power from.

The new AEM Analog gauges are very picky about how you power them. The gauge is designed to zero itself when you switch on the ignition. A lot of the power sources on the Evo X that switch on with the ignition will cut out momentarily during cranking, shutting down the gauge. Because the engine is running when the gauge powers on again, it now zeroes itself to your idle vacuum, giving you a skewed reading.

Read this: https://www.evolutionm.net/forums/ev...m-reading.html

 

using BOV line for the tap isn't the best. my aem is stuck at 4 vacuum for no reason with engine off, not too happy

 

Thank you very much - I did use the cig lighter for power and I suspect this is the problem. Completely missed this thread when searching. Appreciate the help

 

Confirmed that this was the issue - just moved my fuse tap from 13 to 12 and it appears to be reading more reasonable values now. Thanks again.

 

Good to hear.