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Discussion Starter · #1 · (Edited)
It's been a long time since I've posted here, but looking for some help to clarify some not so intuitive grounding instructions for an AEM Infinity. I'm hoping someone on here has built their own harness or has one available to ohm out some pins for me.

I'm currently modifying a milspec harness with OEM Honda connectors to be used with an Infinity and PDM. Which means cutting off the OEM A and B ECU connectors and modifying the C101 connector which supplies 12v power to coil packs, injectors, etc. Using the Kseries Plug and Play harness pinouts as a reference for which Honda pin goes to which Infinity pin. I've ran every wire except the 4 grounds. The pinouts have been pretty clear thus far but I'm stuck on the 4 ground pins. See attached screenshot from the PNP manual.

The PNP manual "Notes" state that Infinity pin 33 goes to chassis. Pin 43 to battery ground. Pin 46 to battery ground. Pin 67 to ground (unspecified).

The PNP manual also specifies Infinity pin 33 to Honda A4 and Infinity pin 43 to Honda A5. The current engine harness has A4 and A5 grounded at the cylinder head. Based on my understanding since those 2 pins are grounded at the cylinder head then 46 and 67 should also be grounded to the same spot. I believe this would follow the star earthing method but I could be mistaken.

To throw a wrench in the gears the Infinity manual for the Infinity contradicts their PNP harness manual and shows all 4 pins to battery ground.

Hoping to get some clarification on how to properly do this.

Thanks in advance.
 

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Arouse the DAMPFHAMMER!
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Pin 67 to ground (unspecified).
I connected it to chassis ground as well as 43 and 46. You find more information to that in Setup Wizard under "actual pinout". It is important to separate the sensor and power ground, not to interfere the sensor ground level with too much electric potential.

he PNP manual also specifies Infinity pin 33 to Honda A4 and Infinity pin 43 to Honda A5. The current engine harness has A4 and A5 grounded at the cylinder head. Based on my understanding since those 2 pins are grounded at the cylinder head then 46 and 67 should also be grounded to the same spot. I believe this would follow the star earthing method but I could be mistaken.
As stated above, the separation of grounding between sensor and power lines is important. Of course both have ideally 0 V potential. In reality it is not as grounded electrons need to flow to ground and the surface of the head is not endless. So there will be a little offset to that 0 V. Therefore separate them by a bigger distance, so that sensor 0 V grounding = 0 V at best as it can.
 

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Discussion Starter · #3 ·
I connected it to chassis ground as well as 43 and 46. You find more information to that in Setup Wizard under "actual pinout". It is important to separate the sensor and power ground, not to interfere the sensor ground level with too much electric potential.
I took a look at the setup wizard and it states chassis ground for all 4 pins. AEM seems to have some inconsistency to their manuals.

As stated above, the separation of grounding between sensor and power lines is important. Of course both have ideally 0 V potential. In reality it is not as grounded electrons need to flow to ground and the surface of the head is not endless. So there will be a little offset to that 0 V. Therefore separate them by a bigger distance, so that sensor 0 V grounding = 0 V at best as it can.
By sensors do you mean 12V sensors that are grounded to the cylinder head?

To summarize what I think you are saying is all 4 pins go to chassis ground? Which in my case would be somewhere on the firewall.
 

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Arouse the DAMPFHAMMER!
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AEM seems to have some inconsistency to their manuals.
The price has it's price. If the Infinity wouldn't have this amazing flexibility (mine controls an EWP via boost controller functionality and many other customized function which I have integrated) I would go with another for my DAMPFHAMMER. But for that price and the MoTec M1 level of control functionalities the lack of documentation (which is huge), especially since their forum was closed by their fear of EPA, they lost a lot of backlog support. I had documented there many of my customized stuff. Now they took the forum from the internet. Unbelievable. But that's CALIFORNIA LOL :D, the unicorn at the front line of emission reduction of the USA.

By sensors do you mean 12V sensors that are grounded to the cylinder head?
I have no documents available at the moment, but you should separate sensor ground wires (0-5 V signals) from those which has higher current and 12 V. The Infinity is quite sensitive regarding oscillating signals like cam, crank. This can relate in a low signal-noise-ratio, loosing crank signal at lower engine speeds happens with a few setups. I never experienced one with an K-series, but there are some in the FB AEM group reporting about these things.

BTW, the FB AEM group is now almost duty for beginners, since the forum was closed.
 

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Discussion Starter · #5 ·
The price has it's price. If the Infinity wouldn't have this amazing flexibility (mine controls an EWP via boost controller functionality and many other customized function which I have integrated) I would go with another for my DAMPFHAMMER. But for that price and the MoTec M1 level of control functionalities the lack of documentation (which is huge), especially since their forum was closed by their fear of EPA, they lost a lot of backlog support. I had documented there many of my customized stuff. Now they took the forum from the internet. Unbelievable. But that's CALIFORNIA LOL :D, the unicorn at the front line of emission reduction of the USA.
Yeah the price compared to others is quite a bit cheaper. I did see they closed the forum which is unfortunate. I didn't realize it was due to EPA regulations but that makes sense. I have seen some posts on there but only able to find them with Google.

I have no documents available at the moment, but you should separate sensor ground wires (0-5 V signals) from those which has higher current and 12 V. The Infinity is quite sensitive regarding oscillating signals like cam, crank. This can relate in a low signal-noise-ratio, loosing crank signal at lower engine speeds happens with a few setups. I never experienced one with an K-series, but there are some in the FB AEM group reporting about these things.

BTW, the FB AEM group is now almost duty for beginners, since the forum was closed.
All 12V sensors are currently grounded at the cylinder head just like OEM. Anything 5V is referenced back to Infinity sensor grounds.

I may just ground the 33, 43, 46, and 67 all to the cylinder head as 2 of them already go there.
 
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