September 30, 2020, 07:05:46 PM

Author Topic: Going standalone - T56 transmission wiring?  (Read 1468 times)

Offline wompa164

Going standalone - T56 transmission wiring?
« on: October 14, 2019, 11:32:45 AM »
I apologize in advance as I know the answer exists on this forum, I just couldn't find it.

After some soul searching, I decided this weekend that I am going to ditch my factory ECU and wiring and try out the Holley Terminator X kit.

There are (3) sensors on my T56 that I unplugged. I believe they are... VSS sensor, reverse lights and reverse lockout?

I am planning on creating a transmission subharness using my stock harness as a donor. I would like to keep this harness separate from my engine harness (or with as few tie-ins as possible) - does anyone have resources they can point me to for making these connections with my chassis harness? I am undergoing a complete chassis rewire so I think I can come up with something clean.

Online largeorangefont

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Re: Going standalone - T56 transmission wiring?
« Reply #1 on: October 14, 2019, 11:47:58 AM »
Well are you are going to need VSS for the stand-alone? The reverse lockout solenoid may need to go to the standalone as well, or you can wire it up on its own switch.
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Offline Exidous

Re: Going standalone - T56 transmission wiring?
« Reply #2 on: October 14, 2019, 12:27:11 PM »
I am using the lights, RLO and VSS all going into my engine harness. The ECU gets the RLO and VSS. A 10amp output is plenty. Only opens RLO below 5mph.
The reverse lights connector is in the passenger foot well so I reused the a couple pins from the factory connector. Just straight from the trans to the body harness through the engine harness. No ECU involvement.
94 BB Sleeved gen IV LS7, MS3ProU with TC, RONIN 8.8 and LT's with custom 3.5"single to VAREX muffler.

Offline bimbleuk

Re: Going standalone - T56 transmission wiring?
« Reply #3 on: October 15, 2019, 03:07:52 AM »
My problem these days is I only do these kind of mods once in a Blue Moon and then forget about them. As my old build thread went poof with a forum I don't document anymore. The T X install only took 3 days and hasn't stopped working sine but I'll try to remember what I can.

I stripped the wires from the old harness I can remember that to re-use the GM connectors. I have two Digital Dakota converter boxes now. One for the VSS to speedo and the other for the RPM out to the RX7 tacho (via the dash harness). It could be done via the Terminator but they've limited the output functions to differentiate their products I assume.

I think I wired the RLO was wired to a spare relay up near my main box in the foot well but I'll have to check how I'n triggering it. May just be wired in with the reverse lights as mentioned above.
« Last Edit: October 15, 2019, 03:16:22 AM by bimbleuk »

Offline digitalsolo

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Re: Going standalone - T56 transmission wiring?
« Reply #4 on: October 15, 2019, 10:42:42 AM »
My standalone controls my reverse lockout and uses VSS.    It does not interface to reverse lights, but you can make them work on the chassis with a relay pretty easily.   FWIW, I've seen reverse lockout functionality in:

MS3
Holley (Terminator/HP/Dominator)
ProEFI
AEM Infinity
Haltech

As far as connections, I ran a 6 pin Deutsch DT connector on the engine harness that ties to a sub-harness on the transmission, and used 18 gauge TXL wire to build it.
Blake MF'ing McBride
1988 Mazda RX7 - Turbo LS1/T56/ProEFI/8.8/Not Slow...   sold.
1965 Mustang Coupe - TT Coyote, TR6060, modern brakes/suspension...  project car
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Offline wompa164

Re: Going standalone - T56 transmission wiring?
« Reply #5 on: October 16, 2019, 02:40:49 PM »
Thank you for the feedback, everyone!

Offline gnx7

Re: Going standalone - T56 transmission wiring?
« Reply #6 on: October 27, 2019, 02:02:32 PM »
Reverse lockout solenoid can also be energized when you tap it into the brake pedal sensor/light.  Depress brake pedal.... it energizes the reverse solenoid to allow reverse to be engaged (12v), voila! 
VSS is 2 wires and most likely needs a translator like Dakota Digital if this is an engine swap car.... reverse lights as stated are basic 2 wires to turn on reverse lights....
'93 FD: 441ci/AllPro LS7 heads/intake en route, T56 Mag, 8.8" IRS, HolleyHP, DavisTechTC 10.32@137mph cats/full exhaust. 165mph 1/2 mile (old LS7)
'93 FD LS9 turbo, T56 Mag, Samberg 8.8" solid axle, 9.35@163mph 197mph 1/2 mile
`69 Chevelle: alum 5.3, GTS76 turbo, ChiseledPerf A/W, T56 Magnum,Ford 35 spline 9".CTS-V interior http://www.norotors.com/index.php?topic=18234.0
old yellar....440rwhp/FD sold but not forgotten: http://www.ponycars.net/scc.htm
I sell new T56 Magnums/McLeod clutch/T56 rebuild kits/Holley EFI/FIC injectors and all BrianTooleyRacing parts.  norcalmotorsport@gmail.com

Offline Cobranut

Re: Going standalone - T56 transmission wiring?
« Reply #7 on: October 27, 2019, 09:54:06 PM »
Reverse lockout solenoid can also be energized when you tap it into the brake pedal sensor/light.  Depress brake pedal.... it energizes the reverse solenoid to allow reverse to be engaged (12v), voila! 
VSS is 2 wires and most likely needs a translator like Dakota Digital if this is an engine swap car.... reverse lights as stated are basic 2 wires to turn on reverse lights....

Interesting, but I'd be a little concerned about engaging reverse when downshifting while braking.

When I bought my FD, the RLO wasn't functional.
I added an extra defogger switch to the blank spot in the console,  and just reach across with my left hand to hold it while shifting into reverse.
1995 FD, 7.0 Liter stroked LS3, T56, 8.8, Samberg kit.

Offline wompa164

Re: Going standalone - T56 transmission wiring?
« Reply #8 on: November 13, 2019, 10:55:54 AM »
Thanks for the input everyone, think I've got this pretty well figured out. After looking at the Mazda wiring diagram I realized the reverse lights were simply passing through the switch on the trans which makes it straightforward. I think I'm going to try to use one of the configurable ECU outputs for the RLO and set it to activate above ~5mph paired with a low-side switched relay.

Offline Exidous

Re: Going standalone - T56 transmission wiring?
« Reply #9 on: November 13, 2019, 11:31:48 AM »
Just so you are aware, you'll need to activate it when below a certain speed. It's normal resting state is locked out and requires power to access reverse without forcing it past the spring tension.
94 BB Sleeved gen IV LS7, MS3ProU with TC, RONIN 8.8 and LT's with custom 3.5"single to VAREX muffler.

Offline wompa164

Re: Going standalone - T56 transmission wiring?
« Reply #10 on: November 13, 2019, 02:25:37 PM »
Oh thanks, I think that's what I meant to say but a good reminder!

Offline wompa164

Re: Going standalone - T56 transmission wiring?
« Reply #11 on: January 13, 2020, 01:28:14 PM »
I have a question on the FD speedometer: what type of signal is it expecting? +5v sinewave?

I finally finished wiring up my Terminator X and went to configure some of the I/Os. I am using the ECU's native transmission features to read the VSS hi/lo signals and create a speedometer output. This is a prerequisite for my reverse lockout relay output which I've programmed to engage over 5mph.

The only output type I can create for my speedometer output is a 12v squarewave. I've calculated and done all of the ppm adjustments in the software, it just seems like a need a way to convert output from +12v square.

Alternatively I could just tap the VSS hi wire from my transmission going into my ECU and use the DD box per existing instructions, but for curiosities sake, what's the best way to do this? Just use my existing SGI-5e box?

Offline wompa164

Re: Going standalone - T56 transmission wiring?
« Reply #12 on: March 30, 2020, 11:13:48 AM »
Well, I got all of this working - thanks for the help everyone.

Unfortunately it seems like I went astray building my standalone transmission harness - whenever the solenoid is active, my VSS signal seems to go crazy. I noticed my speedometer acting erratically, spiking to 80mph at idle. I pulled the fuse for my RLO relay and the issue went away.

I used 16ga for the VSS wires which is probably overkill (should have been 20-22) without any shielding, I'm guessing they are picking up interference from the RLO power wire. I should have twisted them, didn't realize they were that sensitive  :punch: