boost gauge help, aem digital gauge Options

[garin]

i have a 2nd gen 3sgte swapped in a 1995 celica. i installed an aem digital boost gauge. i have the gauge grounded properly an the positive side is connected to the radio fuse. i tried tapping into to locations to get a vacuum reading. first the map sensor line and second on the timing belt side of the the engine, on the intake manifold. i get wrong readings in both cases. i check the aem pressure sensor and everything checks out fine. any suggestion, or wisdom is greatly appreciated.

[garin]

but would that cause the gauge to read 22psi at idle?

[match220]

but would that cause the gauge to read 22psi at idle?

are you sure it's psi and not kpa? my car is 33 kpa at idle according the the autronic display. If your aem boost gauge is like my aem wideband gauge (which I want to sell if anyone is interested) it has a selector switch on the back where you can change the output to the gauge display or to the aftermarket ecu that you are running

[garin]

there is no selector switch on the back.

i figured it out. i used the ignition fuse for power. i just uninstalled everything and rewired it. everything works now. power has to be constant, because the gauge calibrates itself at each key turn. not sure if im s fan of these gauges.

This post has been edited by garin: Mar 31, 2013 - 8:18 AM

[match220]

there is no selector switch on the back.

i figured it out. i used the ignition fuse for power. i just uninstalled everything and rewired it. everything works now. power has to be constant, because the gauge calibrates itself at each key turn. not sure if im s fan of these gauges.

My aem wideband controller/gauge is the same way. I had it wired to a ignition switched power source and it takes a couple seconds to come on before it shows the a/f ratio, so now I turn it on before I turn the car on. I like certain things about it, but I have my eye on another one that has signal and signal ground output wires for aftermarket ecus. The output of mine is inaccurate without the signal ground.

[garin]

these gauges seem to be nice, but quirky at the same time.

[match220]

these gauges seem to be nice, but quirky at the same time.

yeah, I like the look. But as a high quality wideband meter it sucks. I never thought of AEM being incredible, just something that gets the job done, their aftermarket ecus have a lot of dumb tuning flaws but can still be worked with by AEM tuners that know how to work with them. The wideband meter has a signal out, but since it doesn't have a signal ground output then aftermarket ecus cannot accurately determine the voltage output of the sensor. The more expensive wideband controllers output a signal positive and a signal negative. It isn't a big deal on the gauge, the gauge displays an accurate reading since it reads a positive and negative signal from the wideband sensor, and the data log output will be accurate, but the signal output to the ecu is wrong. My autronic reading is always +/- 1 on the air/fuel gauge depending on whether or not I have the headlights on. Also, since i'm running individual coils on my engine, they will pull more electricity at higher rpms, further affecting my air/fuel ratio by changing the overall voltage. It is irritating that the AEM wideband controller is made so crappily. It seems that the signal output is only a selling point and not really a fully functional unit. Again it works great when not feeding my autronic, but sucks on a car that requires accuracy.

I would imagine that the boost gauge is made with the same "love and care" and has flaws of its own.