bloc
SILVER Star
Finally, I come up with something that actually feels like contribution and strictly "tech"...
Big Edit: I forgot to mention that DD advisee caution using this in ABS equipped vehicles. In some of those, the ABS computer compares wheel speed sensor signals to chassis speed, and this can cause problems. Apparently the 80 series ABS isn't sophisticated enough to notice.. Or at least mine isn't. No lights. ABS still works fine (on gravel.) I think this is more of an issue on vehicles with stability or traction control. I just didn't want to completely forget to mention it.
End edit.
When I went to 315s with stock gearing and drivetrain on my 94 FZJ80, as you might expect the speedometer and odometer were no longer accurate. I've installed a SGI-5 made by Dakota Digital on other vehicles, and saw writeups for other toyotas, but nothing specific to the '80 series so here is what I did.
The unit is simple to install and program, and very versatile as far as ability to convert signals.. even going as far as sinewave to squarewave and v/v. About $80, and apparently in the 2 months between buying my SGI-5C and compiling this writeup, it is now obsolete and the SGI-5E is standard. Nice. I'd assume the technical stuff is the same though.
Beyond simple power and ground, you'll need to cut the wire from the VSS (vehicle speed sensor) on the back of the transfer case, where the SGI-5 will make the adjustment, then send the adjusted signal along to the speedometer. To get technical the speedometer then cleans the signal to be sent to the ECU and Cruise.. but that doesn't really matter for what we are doing.
I accessed the necessary wiring by pulling my glove box and tapping into the harness right near the IL1 connector under the dash. Note that my pictures are from a '94.. some wire colors AND PIN POSITIONS may change for 95+.. I originally had pin numbers written down but considering the differences with model years and the fact that anyone doing this should be verifying wire purpose/voltage/status with a multimeter it was possibly more harm than good. So.. consult your EWD or bust out the multimeter.
This did require unbolting the ECU from the mounting location.. but other than the IL1 everything stayed connected.
IL1 is the connector that is disconnected in the above picture. On the "chassis side" of this harness you'll find all of the electrical stuff you need. If you tap the other side of IL1, you'll have to unhook your SGI-5 to pull the engine harness out of the firewall if needed in the future. I advise using the side of the harness that is most visible.
Here you can see my taps and interrupt.
White/Black is ground. This is a theme throughout everything toyota does.
Solid Yellow is the VSS +12v signal, and is switched on by the key. I tapped into this with a red wire for the SGI-5
Green/Red strip is the VSS signal wire to the combination meter. You need to cut this wire, and run the appropriate ends to the SGI-5. I used male and female sides of a barrel connector so that if I need to uninstall the SGI-5 later, it is as simple as hooking this wire back together. I ran two color stripe versions of green wire to the SGI-5 to keep things straight. Green/Yellow from the SGI-5 to the comb. meter, and Green/white to the VSS
Make sure nothing will short, reconnect IL1, apply something to wrap up your 4 wires, and tuck the wiring out of the way.
Now wrap your 4 wires and find a location for the SGI-5. I used some double sided foam tape to attach it behind the left dash speaker grill, where the factory amp was previously located.
Now, specific settings and wiring.
White/black goes to GROUND
Yellow (now red for me) goes to POWER.
Run the wire from the VSS side of the harness to the "Input" terminal.
Run the wire going to the combination meter to the "Out 2" terminal.
Out 1-4 are for different applications, and the manual is a bit confusing as to what we actually need. Through trial and error, I found Out 2 and the dip switch settings seen here as effective.
Dip switches 1-3, off
Dip 4, on
Now you can try and turn on the key to see whether the unit has power.. The green light should stay on solid if the power is on but the vehicle is not moving.
Beyond that, it is just calibration. I did some math based on the published rev/mile numbers of my old and new tires, and worked out that I needed to speed up my VSS signal by a factor of 1.113. There is a large chart in the directions showing what "course" and "fine" settings are needed to achieve this. In my case, course:2, fine:10.
For Course adjustment, hold the UP button while turning on the key. The Red light will turn on. When you release the UP button the green light turns on, then red will start flashing the current "course" setting. use UP/DN to get whichever value you need. Then turn the key off.
For Fine adjustment, hold the DN button while turning on the key. Things will be similar with the lights.. just use UP/DN to get your value, then turn off the key.
As you drive, the green light should be flashing. This is a sign that the SGI-5 is receiving a pulsed signal.
At first I had the wrong output and dip switch settings, but the stuff outlined above is what got it working.
Based on stock LTXs, and me going to 315/75/16 BFG KM2 tires, as mentioned the math worked out to 1.113. But once out on a roadtrip I used some mile markers over about a tank of fuel to fine tune things.. turns out 1.094 is closer to the actual value. (course:2, fine:6) And for the record, I personally tried to dial in the Odometer, as I'd prefer that be spot-on than the speedometer.
Hopefully this helps someone out.. if you have any questions I'll try to answer.
And if anyone is following the saga of my rolled cruiser.. I bought the white 97 body and am currently collecting the needed panels, shop space and tools to move it over. The front clip likely won't be white.. so I'm mulling over my options for bed liner down the sides of the rig..
Big Edit: I forgot to mention that DD advisee caution using this in ABS equipped vehicles. In some of those, the ABS computer compares wheel speed sensor signals to chassis speed, and this can cause problems. Apparently the 80 series ABS isn't sophisticated enough to notice.. Or at least mine isn't. No lights. ABS still works fine (on gravel.) I think this is more of an issue on vehicles with stability or traction control. I just didn't want to completely forget to mention it.
End edit.
When I went to 315s with stock gearing and drivetrain on my 94 FZJ80, as you might expect the speedometer and odometer were no longer accurate. I've installed a SGI-5 made by Dakota Digital on other vehicles, and saw writeups for other toyotas, but nothing specific to the '80 series so here is what I did.
The unit is simple to install and program, and very versatile as far as ability to convert signals.. even going as far as sinewave to squarewave and v/v. About $80, and apparently in the 2 months between buying my SGI-5C and compiling this writeup, it is now obsolete and the SGI-5E is standard. Nice. I'd assume the technical stuff is the same though.
Beyond simple power and ground, you'll need to cut the wire from the VSS (vehicle speed sensor) on the back of the transfer case, where the SGI-5 will make the adjustment, then send the adjusted signal along to the speedometer. To get technical the speedometer then cleans the signal to be sent to the ECU and Cruise.. but that doesn't really matter for what we are doing.
I accessed the necessary wiring by pulling my glove box and tapping into the harness right near the IL1 connector under the dash. Note that my pictures are from a '94.. some wire colors AND PIN POSITIONS may change for 95+.. I originally had pin numbers written down but considering the differences with model years and the fact that anyone doing this should be verifying wire purpose/voltage/status with a multimeter it was possibly more harm than good. So.. consult your EWD or bust out the multimeter.
This did require unbolting the ECU from the mounting location.. but other than the IL1 everything stayed connected.
IL1 is the connector that is disconnected in the above picture. On the "chassis side" of this harness you'll find all of the electrical stuff you need. If you tap the other side of IL1, you'll have to unhook your SGI-5 to pull the engine harness out of the firewall if needed in the future. I advise using the side of the harness that is most visible.
Here you can see my taps and interrupt.
White/Black is ground. This is a theme throughout everything toyota does.
Solid Yellow is the VSS +12v signal, and is switched on by the key. I tapped into this with a red wire for the SGI-5
Green/Red strip is the VSS signal wire to the combination meter. You need to cut this wire, and run the appropriate ends to the SGI-5. I used male and female sides of a barrel connector so that if I need to uninstall the SGI-5 later, it is as simple as hooking this wire back together. I ran two color stripe versions of green wire to the SGI-5 to keep things straight. Green/Yellow from the SGI-5 to the comb. meter, and Green/white to the VSS
Make sure nothing will short, reconnect IL1, apply something to wrap up your 4 wires, and tuck the wiring out of the way.
Now wrap your 4 wires and find a location for the SGI-5. I used some double sided foam tape to attach it behind the left dash speaker grill, where the factory amp was previously located.
Now, specific settings and wiring.
White/black goes to GROUND
Yellow (now red for me) goes to POWER.
Run the wire from the VSS side of the harness to the "Input" terminal.
Run the wire going to the combination meter to the "Out 2" terminal.
Out 1-4 are for different applications, and the manual is a bit confusing as to what we actually need. Through trial and error, I found Out 2 and the dip switch settings seen here as effective.
Dip switches 1-3, off
Dip 4, on
Now you can try and turn on the key to see whether the unit has power.. The green light should stay on solid if the power is on but the vehicle is not moving.
Beyond that, it is just calibration. I did some math based on the published rev/mile numbers of my old and new tires, and worked out that I needed to speed up my VSS signal by a factor of 1.113. There is a large chart in the directions showing what "course" and "fine" settings are needed to achieve this. In my case, course:2, fine:10.
For Course adjustment, hold the UP button while turning on the key. The Red light will turn on. When you release the UP button the green light turns on, then red will start flashing the current "course" setting. use UP/DN to get whichever value you need. Then turn the key off.
For Fine adjustment, hold the DN button while turning on the key. Things will be similar with the lights.. just use UP/DN to get your value, then turn off the key.
As you drive, the green light should be flashing. This is a sign that the SGI-5 is receiving a pulsed signal.
At first I had the wrong output and dip switch settings, but the stuff outlined above is what got it working.
Based on stock LTXs, and me going to 315/75/16 BFG KM2 tires, as mentioned the math worked out to 1.113. But once out on a roadtrip I used some mile markers over about a tank of fuel to fine tune things.. turns out 1.094 is closer to the actual value. (course:2, fine:6) And for the record, I personally tried to dial in the Odometer, as I'd prefer that be spot-on than the speedometer.
Hopefully this helps someone out.. if you have any questions I'll try to answer.
And if anyone is following the saga of my rolled cruiser.. I bought the white 97 body and am currently collecting the needed panels, shop space and tools to move it over. The front clip likely won't be white.. so I'm mulling over my options for bed liner down the sides of the rig..
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