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fwdsrt4
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Last seen: 7 months 4 weeks ago
Joined: 09/17/2016 - 14:07
EMS4 and 30-0300

The ems 4 has 4 wires for connection to AFR. Am I able to power the AEM Wideband gauge, which powers the sensor, with the 12v wire that is part of the four wires provided by the harness? The calls for 12v switched with a 5amp fuse. Can I expect that since my EMS4 is on the ignition switch, that powering it up with the AEM wide band gauge/sensor, and everything else that powers on by the EMS4 when the EMS comes up, will be ok?

AEM_NS
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Last seen: 5 hours 13 min ago
Joined: 06/06/2014 - 09:31
Do you mean that the EMS-4

Do you mean that the EMS-4 has 4 wires for the AEMnet CAN-Bus? The AEMnet lead is usually made from cable which has a fairly small wire gauge as it's really only intended to communicate with and power low current AEMnet devices.  It's not a good idea use the 12v and ground in the AEMnet connector to power a UEGO gauge.  Wire your 0300 gauge like the instructions show.

One thing I want to point out is that the EMS-4 (and Series 2) do not support the X-Series AEMnet channels.  You can still use your 0300 with the EMS-4 but you'll have to input the AFR data through the O2 sensor analog input (pin 20).

fwdsrt4
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Last seen: 7 months 4 weeks ago
Joined: 09/17/2016 - 14:07
"Do you mean that the EMS-4

"Do you mean that the EMS-4 has 4 wires for the AEMnet CAN-Bus?" No. At least I don't think so. I mean to say there are four individual wires on the  30-2905-96 Full Harness.
Labeled like

AFR - White pin 20 O2 Sensor input. - Connect to 03-0300 Pin 9 White 0-5v Analog Output Positive
SIG GND - Black Sig GND Splice - Connect to 03-0300 Pin 10 Brown 0-5v Analog Output Negative
PWR - Red PWR SPL ICF - Connect to 03-0300 Pin 1 Red Switched 12v Power (5a Fuse)
PWR GND - Black GND SPL ICF A - Connect to 03-0300 Pin 2 Black Power GND

Is this connection supported? I know that a sensor warm up can be a bit if a drain?

I would guess that if you are trying to use O2 feedback when the engine starts, but the O2 is not completely online, that could be an issue?
 

AEM_NS
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Joined: 06/06/2014 - 09:31
Ah ok, sorry my bad. I

Ah ok, sorry my bad. I looked at the schematic for the full -96 harness and we did supply a full bundle of power and ground for a UEGO gauge. Yes, that should be fine to use to power the 0300 gauge. I had incorrectly presumed that the UEGO input would have been a single flying lead wire so when you mentioned four wires, I presumed you meant AEMnet since the X-Series gauges have AEMnet.

The 5A fuse between the gauge and the power wire is still a good idea.

Thr33GenAccord
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Last seen: 7 months 2 weeks ago
Joined: 02/24/2017 - 10:46
Hey guys, 

Hey guys, 

Supernoob here again to revive this thread for a minute. I'm in the process of building a spreadsheet that will help me confidently attack the rest of the full harness for the EMS-4.  It's beautiful that you guys went to the trouble of supplying and PWR and PWR GND in the afr bundle on the harness.  That being said, if I have my AEM UEGO afr gauge powered and lit up already, can I just insulate and ignore (or repurpose) those two wires and just use the AFR ans SIG GND for the Lambda (+) and Lambda (-) from the gauge?

Really appreciate any assistance,  I have car audio and security background but this is my first engine/drivetrain swap and my first ems install.  Be gentle... cheeky

AEM_NS
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Last seen: 5 hours 13 min ago
Joined: 06/06/2014 - 09:31
Yes, if you're not using

Yes, if you're not using those wires, just insulate them and isolate them away from other stuff. If you're new at this, be sure to read the DIY/FAQ EMS-4 thread.