How do I connect a XDCR to read boost??

[KEVINS]

I don't know ANYTHING about electricity so I'm having issues with wiring up an AEM XDCR (0-100psi p/n 30-2130-100) to read boost. Can someone help me?

The XDCR has 3 pins:

Sensor Power (5Volts)
Signal Ground
Signal

Initially I had the SIGNAL GROUND wire connected to the sheet metal of the car but at idle the logger was reading 11psi of boost.
Yesterday I learned that SIGNAL GROUND is different than CHASSIS GROUND so today I switched the wire to a Wire coming from the ECU that is labeled GROUND. Now the data logger is reading 15psi of boost at idle...aaarrg.

-I have the SENSOR POWER wire connected to a MAP wire that has 5 volts to it when the key is turned on. This is verified with a meter.

-I NOW have the SIGNAL GROUND wire going to a wire coming out of the ECU that is labeled GROUND. (Should this be connected to sheet metal or a Ground wire from the ECU?)

-The SIGNAL wire goes to my data logger.

Is this wired correctly? If not how do I wire this thing up?

TIA
ks

 

[KEVINS]

I called AEM and I currently have it connected properly. The Signal Ground wire DOES get connected to a Ground wire from the ECU and not sheet metal.

ks

 

[aminga]

The ECU is technically grounded to the block. THat's where I have all my sensors grounded to.

 

[Phoneguy]

i dont have a powerlogger but you will need to make an entry in the logger software to let it know how to reference this transducer as it has no idea what is connected to it. I would have gone with a different transducer for boost so that you had better resolution. You will never use 65% of the resolution you have right now
Bryan

 

[dynoman]

Do you have a Powerlogger or another data logger ? If you have a Powerlogger why don't you use the map sensor signal for logging boost ? Works for me .

 

[KEVINS]

Thnx guys.
I ordered a GM 4bar since my data logger has to read 0-5v not 0.5-4.5v.

All taken care of!

KS

 

[KEVINS]

Bringing this back up.

The 4bar MAP didn't resolve my issue and I discovered that my data logger is cheap enough that I cannot program the voltage offsets of the xdcr to for the voltages that the Diablo needs in order to log the proper data.

However, I was informed that an OP Amp can be used to to alter these voltages out of the xdcr so the data logger will see the proper voltages so I have an Electrical Engineering buddy who's going to make me an op-amp circuit to do this.

My Question:
I want to make sure I correctly explain what I need to him and if I understand this correctly I want:

1. The voltage to read 0V (key on/engine off) going into the data logger, correct?

2. Then I want it to read 5V at max psi of the xdcr (4-bar MAP = 43.5psi), correct?

ks