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AEM wideband not sending full voltage to ecu

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AEM wideband not sending full voltage to ecu

Old 03-13-2018, 10:45 AM
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Default AEM wideband not sending full voltage to ecu

Not sure if this is the right place for this or not. But letís start with saying Iíve got a turbo Miata out it together about 2 years ago. Pretty standard setup ms2pnp with begi mani and dump sr20 turbo and the rest pieced together. I originally used an innovate mtxl wideband wired per there instructions relay coming off the battery with switched power running the signal into the appropriate option port. Everything was fine and dandy got the car road tuned and just drove it as it was for a while. I came back about 5 months later to change some settings and the ecu is not receiving a signal from the wideband checked all my connections to make sure nothing came loose and itís all intact checked the voltage the wire was outputting and nothing. Replaced the sensor it worked again but just for a bit again it eventually died the car had a decent tune on it so I drove it for a while and just turned off any ego correction and the like to prevent it compensating for it thinking it was super rich. Anyway made some winter changes one being I swapped over to an aem uego wideband. Hooked it up per there instructions I still use the relay from the innovate setup but itís basically the same thing. Anyway it worked for a while then it did the same thing stopped sending a signal to the ecu. Went back redid all the wiring for the gauge just to be safe replaced the sensor and again same thing itís only outputting like 0.5v instead of the full voltage. So can anyone maybe give me some advice as to what Iím doing wrong or how I can install something to be a fail safe so I donít have to keep replacing the sensor.


Tldr: my aem wideband sensors keep breaking and sending the incorrect signal to the ecu. How can I prevent the sensor from dying.
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Old 03-13-2018, 10:55 AM
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Some commas would really help to read your paragraph.

How close is the O2 sensor to the turbo? Do you have the sensor ground hooked up? I think it's a brown wire.

I think you have two separate issues, one that sensors fail prematurely and the other that the new gauge isn't working.

Some tips for extended sensor life:
-Make sure the O2 sensor is installed at least 18" from the turbo (usually at the start of midpipe is a good location), and angled upwards (so moisture cannot pool in the sensor)
-Most manufactures don't note this in the instructions, but the power for the wideband should only be active when the engine is running. Otherwise you will heat the sensor with no air flow, then when the engine starts it'll blow cold condensed air over the hot sensor and wear it down really quick. The relay you have powering your wideband should be triggered from the fuel pump output.
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Old 03-13-2018, 11:34 AM
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Sorry for the punctuation. It has never been a strong suit of mine.

Thanks for the advice, I currently have a begi downpipe and mani so I don’t think location is an issue, it’s at the start of my midpipe. The power is only active on the final key switch I’ve sourced the switch power off the 12v switched source from the option plug on the ecu. Would you still recommend changing switch source to hook into the fuel pump wires?

As for the ground I have the sensor plugged into the gauge like it goes and then from the gauge I have it grounded to the battery ground so i could guarantee it’s solid. I don’t know if that’s bad practice or not but that’s what I currently have.

I dont know if I said the gauge was working or not, but the gauge its self the physical one I have in my dash works fine it’s just the output to the ecu. As soon as i replace the sensor in the exhaust and plug it in the ecu can read it just fine. They just don’t seem to want to last more than a month before not sending a signal to the ecu.
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Old 04-22-2018, 12:23 PM
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Does anyone have any ideas on this? I'm dealing with a very similar issue.

I have the AEM X Series WB. The sensor reads the AFR and prints it onto the gauge perfectly fine. However, the ecu isn't receiving any voltage from the gauge.

I, too, have checked for continuity and voltage on the output wires to the ecu. Continuity checks out but I get nothing for voltage.
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Old 04-22-2018, 01:01 PM
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Originally Posted by Artifex View Post
I, too, have checked for continuity and voltage on the output wires to the ecu. Continuity checks out but I get nothing for voltage.
You're trying to read voltage between the brown and white wires?
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Old 04-22-2018, 01:29 PM
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Originally Posted by Artifex View Post
Does anyone have any ideas on this? I'm dealing with a very similar issue.

I have the AEM X Series WB. The sensor reads the AFR and prints it onto the gauge perfectly fine. However, the ecu isn't receiving any voltage from the gauge.

I, too, have checked for continuity and voltage on the output wires to the ecu. Continuity checks out but I get nothing for voltage.
I think with my issue I was running too rich and fouling sensors out. But Iím not conclusive. I moved my ground wire thinking maybe it wasnít a good one. Didnít see any changes. Guess Iíll order a new sensor and give it another shot.
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Old 04-22-2018, 01:33 PM
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Correct. So with the car on engine off the gauge reads full lean. It should be sending ~5 volts to MS, right? I am getting nothing. Therefore, in TS it shows full rich. At idle and free revving the TS reading is unchanged.
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Old 04-22-2018, 02:13 PM
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The X-Series will sometimes not output a signal if the engine hasn't started and may in fact delay the signal even after the engine has actually started.
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Old 06-18-2018, 09:45 PM
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Originally Posted by Artifex View Post
Correct. So with the car on engine off the gauge reads full lean. It should be sending ~5 volts to MS, right? I am getting nothing. Therefore, in TS it shows full rich. At idle and free revving the TS reading is unchanged.
Did you get this resolved? Iím facing the same issue getting a signal to TS. I have a Brain built ms3x and I tapped into the stock 4 wire narrowband.
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Old 06-18-2018, 10:25 PM
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Originally Posted by HeavyD View Post


Did you get this resolved? Iím facing the same issue getting a signal to TS. I have a Brain built ms3x and I tapped into the stock 4 wire narrowband.
Yes, I did. My problem was MS was trying to get the sensor input from the wrong location/pin. A quick change of settings and voila. I have my WB wired into the options plug though. I did not use the stock o2 plug at all.
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