Hey friends,

I have installed a Defi-Link ADVANCE Control Unit SE, the Defi-Link Meter ADVANCE FD, and the Turbo/In-Mani sensor. The ADVANCE FD is reading my sequential turbos perfectly. Zero complaints thus far. In the coming days, I will work on the wiring of water, oil, and oil press sensors. All these have been pretty straightforward thus far. However, I am having trouble confirming which wires on my ECU harness I need to splice to enable the ADVANCE FD to read my speed and tachometer. I'm having difficulty deciphering with 100% confidence the various ECU wiring diagrams I've collected from this site. I am hoping the community can help provide me with a clear answer.

I have a 1997 FD RS-R with the stock ECU N3F1 18 881A.

Thanks in ADVANCE (pun intended)

 

4Q seems to be your speedo signal
your tach signal you will have to guess and check with the CAS wires. the BEE-R uses them to determine RPM so i imagine the defi will be the same. you can just back probe the pin and see if it registers on the defi

 

Thank you for the informative screenshots! I will certainly reference them when I resume work on my FD over the weekend

 

Looking over your attachments led me to browse the Haltech site, where I found a pinout for series 7/8 FDs. You were correct about 4Q for my speedometer, so again, thank you for your help. Gonna back probe 3R for the tachometer. Nonetheless, I figured I should attach it here for posterity purposes.

 

Okay, I back-probed 3R, and the DeFi Advance FD display is significantly off. At idle, about 900 RPM, the display shows approximately 4400 RPM. I have some other tasks I want to complete on my RX-7 over the long weekend, so I will resume wire testing in the coming days. In the meantime, I'm curious if anyone else has had a similar experience.

 

Try 3S and 3U 🤔

 

Interesting update. When I back-probe 3U and set the cylinder count to 2, it correctly reports the RPM within an expected variation of 10%. However, the DeFi ADVANCE FD manual explicitly states that the cylinder count should be set to 4 for two-rotor engines, and for three-rotor engines, it should be set to 6. While I can see the correct RPM reading, I am uncomfortable sticking with these current settings, knowing they counter what the DeFi manual instructs one to do. Back to troubleshooting, I go.

 

I wouldn't worry about it. The way rpm signals work and are interpreted, there's no harm being done with having it set that way. You may end up looking for a ghost with this one

 

I appreciate reading this; I definitely would have stubbornly gone after the ghost. I will heed your warning and remind myself that it is reporting back accurate data, and that's what matters. I'm sticking with 3U and will work on the permanent wiring this week. I really appreciate your help. Thank you!