PFC Datalogit w/ AEM Uego Questions

[fliprayzin240sx]

K, I'm trying to see if somebody can shed some light on this. I started attempting to datalog my setup but for some reason, the numbers I'm logging is off to what I'm seeing on the gauge. I'd be seeing 10.5 on the gauge but I'm logging 11-12 AFR. I got the Delta AN1-AN2 setup as V 0-5 and Value 10-20 A/F. Running with the default poly of y=ax^2 + bx + c, with a=0, b=2 and c=10.

I'm reading some saying that the default settings are good but some are saying that they're running b=1.76 and c=8.8. Curious to see if anybody is running something else for the calculation?

[inopsey]

do you have the calibration table for the eugo (voltage vs afr)? is 10 and 20 afr really 0 and 5 volts respectively? thats the first thing to figure out. also do not assume the sensor functions linerally, try to add atleast 3 calibration points.

[fliprayzin240sx]

^^^Found a table and it is indeed 10/20 for 0-5v. 0 is 10v and 4.99 is 19.98. Is it possible that the logger is just not quick enough to keep up with the changes? I got the Hold off (mSec) set at 20 from what I've seen from the RX-7 forum.

[fliprayzin240sx]

Am i doing anything wrong?
http://i58.photobucket.com/albums/g254/fliprayzin240sx/AFRLog_zpsa91b42c9.jpg

[inopsey]

Am i doing anything wrong?
http://i58.photobucket.com/albums/g254/fliprayzin240sx/AFRLog_zpsa91b42c9.jpg

can you not enter 4.99v and 19.98af into the datalogit, being exact might clear up the resolution in that area.

you can graph the equation y=ax2+bx+c. a=0 so it is a straight line. you have the entire range of voltage for the af meter. you can graph that. check to see if the slope is the same. the area you are concerned with is the 14-10afr find the slope of that area.

[fliprayzin240sx]

can you not enter 4.99v and 19.98af into the datalogit, being exact might clear up the resolution in that area.

you can graph the equation y=ax2+bx+c. a=0 so it is a straight line. you have the entire range of voltage for the af meter. you can graph that. check to see if the slope is the same. the area you are concerned with is the 14-10afr find the slope of that area.

You just spoke alien to me at that point...where do I see the AF meter graph at? I'm new to this whole datalogger tuning thing. Are you talking about the Air Flow Curve under Setting 3?

[inopsey]

You just spoke alien to me at that point...where do I see the AF meter graph at? I'm new to this whole datalogger tuning thing. Are you talking about the Air Flow Curve under Setting 3?
you have to make the af voltage graph using the data points given by the manufacture on the calibration table. draw that out with paper or a graphing calculator. compare the slope to the one on the datalogit using y=bx+c format. you might have to adjust the c=10 to c=8 to change the slope in the datalogit making it match the one from the calibration table.

[fliprayzin240sx]

Ahhhh...got you...

[Kingtal0n]

you dont have to play with the polynomial. Just look in the instruction manual, it tells you what the voltage output is at what a/f ratio. make sure you run the sensor ground to the AN2 input on the data-logit.

If the number still doesnt match (wideband vs computer) then get a volt-meter and verify the accuracy of the voltage output. I have seen a brand new out of the box AEM wideband report the wrong voltages-
bad unit out of the box!

[Kingtal0n]

also, you should be able to get decimals logged for air/fuel values. And you want to play with the Hold off (msec) delay for differential situations. I always start my tunes with 2ms delay so it logs nearly every spot, then while you go over the data-log later, use intuition to decide what values are legit. You can walk the graph forward and backward with the mouse and watch the box move as if the car was running.

later on, for a 1 hour highway drive or something, change the msec to about 40 or 80 or even 200+. That way it will not log any quick transitions.

[fliprayzin240sx]

Sounds like its time to bust out my old LM-1...I have not been impressed with this shity AEM wideband.

[Kingtal0n]

did you put a volt-meter on it and compare the output voltage to the chart in their manual? If it doesn't match, send it back.

also, where is the sensor located? It has to be far enough from the turbo that it will not overheat. The temperature will change the reported A/F ratio.

[inopsey]

did you put a volt-meter on it and compare the output voltage to the chart in their manual? If it doesn't match, send it back.

also, where is the sensor located? It has to be far enough from the turbo that it will not overheat. The temperature will change the reported A/F ratio.

you dont need to put a voltmeter on it; the pfc datalogit will read the voltage it is receiving at the datalogit input. you can change it from reading afr to voltage in the software. theres probably nothing wrong with the af meter because it is reading correctly at the eugo gauge, just not at the datalogit. you could put in a resistor to correct the voltage being read by the datalogit.

[Kingtal0n]

you dont need to put a voltmeter on it; the pfc datalogit will read the voltage it is receiving at the datalogit input. you can change it from reading afr to voltage in the software. theres probably nothing wrong with the af meter because it is reading correctly at the eugo gauge, just not at the datalogit. you could put in a resistor to correct the voltage being read by the datalogit.

you dont NEED to do anything. He can plug the single wire into the data-logit, and throw the a/f numbers into it from the manual, and go like that start driving. Now you are driving and either [it works perfect] OR [the numbers do not make sense, something must/could be wrong]. In the case of the latter, you would want to verify the voltage being reported by a multi-meter reflects the voltage being reported by the computer.

Its the same idea behind ignition timing: the computer reports a value, but we must suspect this value at all times because there is no guarantee that the timing value in the computer display matches the timing at the crankshaft actual BTDC.

Before we decide that the AEM is suspect, a quick scan with the multi meter will assist/help verify.

theres probably nothing wrong with the af meter because it is reading correctly at the eugo gauge
we cannot just assume this is true. I have personally been witness to a brand new AEM gauge reporting accurate values on the display and bad values in the analog output.

[Kingtal0n]

more screen shots and logs of the car driving. get a log up that shows injector duty, throttle position, rpm. time spent with the graphing utility helps you learn about sensor behaviors.

[inopsey]

you dont NEED to do anything. He can plug the single wire into the data-logit, and throw the a/f numbers into it from the manual, and go like that start driving. Now you are driving and either [it works perfect] OR [the numbers do not make sense, something must/could be wrong]. In the case of the latter, you would want to verify the voltage being reported by a multi-meter reflects the voltage being reported by the computer.

Its the same idea behind ignition timing: the computer reports a value, but we must suspect this value at all times because there is no guarantee that the timing value in the computer display matches the timing at the crankshaft actual BTDC.

Before we decide that the AEM is suspect, a quick scan with the multi meter will assist/help verify.


we cannot just assume this is true. I have personally been witness to a brand new AEM gauge reporting accurate values on the display and bad values in the analog output.

the only way to confirm if the af sensor is working properly is to install another known working af sensor. checking the voltages does nothing to solve the problem except say that aem makes shady electronics; (one 3-4 wire sensor putting out different voltages) and can be done by making the datalogit log voltage not afr.

checking the voltage at the datalogit/analogue output will tell you that it is reading a different voltage than the uego gauge. (obviously if he is getting a different reading at the datalogit vs gauge and the software is scaled correctly) doesent matter what the voltage is since it can be corrected in the software to read correct afr. (the whole purpose of this?) if the eugo has both digital (going to the uego gauge) and analogue signal outputs (ecu output) separate then confirm the afr with a second af sensor and tap the signal from the gauge wire to the datalogit. i doubt very much that a single output wire(digital signal to uego gauge) is capable of transmitting 2 different signals from the same wire providing proper grounding/attaching. now that you have confirmed the uego is reading correct afr (tail pipe reading etc) with a second af sensor correct the signal in the datalogit and go tune/log.

[Kingtal0n]

the only way to confirm if the af sensor is working properly is to install another known working af sensor. checking the voltages does nothing to solve the problem except say that aem makes shady electronics; (one 3-4 wire sensor putting out different voltages) and can be done by making the datalogit log voltage not afr.

checking the voltage at the datalogit/analogue output will tell you that it is reading a different voltage than the uego gauge. (obviously if he is getting a different reading at the datalogit vs gauge and the software is scaled correctly) doesent matter what the voltage is since it can be corrected in the software to read correct afr. (the whole purpose of this?) if the eugo has both digital (going to the uego gauge) and analogue signal outputs (ecu output) separate then confirm the afr with a second af sensor and tap the signal from the gauge wire to the datalogit. i doubt very much that a single output wire(digital signal to uego gauge) is capable of transmitting 2 different signals from the same wire providing proper grounding/attaching. now that you have confirmed the uego is reading correct afr (tail pipe reading etc) with a second af sensor correct the signal in the datalogit and go tune/log.

I doubt he has an extra sensor laying around. your post is kind of confusing. the digital wire that goes to the gauge display should not be utilized or tested. the analog output for the fc-datalogit should be verified by a multi meter.

[fliprayzin240sx]

did you put a volt-meter on it and compare the output voltage to the chart in their manual? If it doesn't match, send it back.

also, where is the sensor located? It has to be far enough from the turbo that it will not overheat. The temperature will change the reported A/F ratio.

Its in the DP, far enough down stream from the turbo, roughly 36-40 inches.