After looking at this document: http://aemelectronics.com/files/inst...Play%20EMS.pdf

It appears that the AEM ECU doesn't have an input channel for a digital pulsed input. Therefore some kind of device would be required that can diagnose the signal and/or convert it to a 0-5v analog output (i.e. the Zientronix gauge).

The document says that a boost solenoid should be wired to pin D16.

Four 0-5v analog voltage inputs exist; they are A29, C6, C24, and D8.

This info applies to the Series 2 ECU, P/N 30-6052

 

Anyone know since we are going to need a gauge now or something to change the single if the Zientronix round gauge will work or if something else is need with it to change the singal.

 

Good find coolguy. I did something similar. For the AEM guys I used D12 switch 3 and in the settings switch always off. (there's a post on it somewhere) You should be able to verify that the sensor is working correctly with the key on engine off. If you have pump gas it usually read e08 or e10

 

Is that for version 1 or 2?

 

You're talking about the ECA-2? http://zeitronix.com/Products/ECA/ECA2.shtml

Yes, that also has the dual 0-5v analog output signals that can then be tied into a regular analog voltage input on the ECU.

 

I was told you could hook it right to the ems without a gauge ..is this not true?

 

You can IF your EMS has an input for a digitally pulsed signal.

About to get a bit tech-y here, but hang in there with me. The flex fuel sensor connector has three wires. One is a +12v power source, one is a ground, and one is the signal output. That signal output comes in the form of a square-wave digital signal. The signal can vary in frequency and pulse width, and each of these two variables is what gives information about the fuel. The frequency of the signal relates to the ethanol content (what we are really after) and the pulse width relates to the temperature of the fuel. The voltage of the output signal is NOT linear from 0-5v as it relates to ethanol content alone. Therefore, you can't just hook the one output wire directly from the sensor to a 0-5v analog input on an ECU. You need an input channel on your ECU that can interpret the frequency and pulse width of that incoming signal and accurately relay info on the ethanol content and/or fuel temperature independent of incoming voltage.

Alternatively, you can use another device to interpret the digital pulsed signal from the sensor for you. The Zeintronix gauge will do this and output two separate 0-5v analog signals, one for ethanol content and one for fuel temperature. These analog signals can then be fed into the ECU into a standard 0-5v analog input channel.

Haltech offers a separate I/O unit that has digital pulsed inputs on it, so if you had this unit you could feed the signal wire directly from the sensor to this Haltech unit, then plug that unit into your Haltech ECU. Another user on this forum figured that out a while back.

FYI - For the digital pulsed signal frequency, 50 Hz represents 0% ethanol and 150 Hz represents 100% ethanol. Similarly, a pulse width of 1 ms represents -40 degC and 5 ms represents 151.25 degC. Each manufacturer of a conversion unit (like the Zeintronix gauge) will give you charts that show the relationship of fuel content and fuel temperature to the 0-5v analog signal.

 

So anyone running anyone will have to get the interpreter, correct?

 

I think this is what you meant?

I don't know much about the AEM ECU's, but if they don't have a digital pulsed input then yes you will need a signal interpreter like the Zeintronix.

From what I saw in that manual up there, I don't think there is a digital pulsed input channel to be used on the AEM ECU, but don't quote me on that.

 

I understand what you are saying coolguy, but that doesn't make sense to me, AEM v2 supports the flex fuel option, for use with a gm flex fuel sensor. If the AEM couldn't interput the signal, how are they getting it to work?

It supports it, anyone talk to AEM, what they recommend?