novaragtop

I've been driving my car for 3 months without a working speedo. I have not found any new info on how to make it work, other than on the site I put a link to at
https://www.circuitlab.com/circuit/7...edo-converter/

Has anyone tried this? I would like someone who knows something about electronics to "decode" or explain to me what is being done in this circuit, and break it down to which wire comes and goes where?
I have had my ECU set with HP tuners for the correct tire size, and set to 16,000PPMs, and gone directly to the back of the speedo to place a separate ground wire to the gage and placed the resistor on the ground wire, and run a separate wire to the Signal terminal on the gage, and placed the capacitor in the wire coming from the ECU speedo signal out wire and connected it to the gage signal terminal.
I installed a new VSS vehicle speed sensor in the T-56, and I'm using a new painless wiring harness.
Your help is appreciated.
Thanks
rand24r@telus.net

LS1-450

iTrader: (33)

Looks like resistor & capacitor mount in the same wire from the PCM output to the gauge.

novaragtop

Here is more info form the fellow that designed this. Another guy confirmed it worked.

http://ekwang.wordpress.com/

novaragtop

Any one else care to chime in on what the designer intended to demonstrate in the schematic?
There are 4 terminals on the back of the electric speedo head. A ground, a signal, an Ignition, and the fourth goes to the Nissan ECU terminal 32, which will cut the ignition when the speed limit is exceeded. This terminal in now void. Ignition wire would supply voltage to electric speedo.
I have run two wires , one from the ground terminal, and one from the Signal terminal, and run the wires to the LS1 ECU. There is a green wire labeled VSS OUT that I connected to the negative side of the capacitor, and the Positive side to the Speedo Signal wire. I had put the resistor in the ground wire before attaching it to the chassis. I have reset the ECU by disconnecting the battery and stepping on the brake pedal for several minutes.
HP tuners was used to set correct parameters for diff and tire circumference.
Where would you put the resistor if using the wires I have for connections?
I figure I can't be wrong going directly to speedo this way???? Thanks for helping.

jamesgr81

The capacitor will charge and discharge though the resistor changing the pulse to a sine wave. Not a very good sine wave though.

The VSS wire from ECM should be connected to + side of capacitor.

2muchboostNY

iTrader: (8)

Pick up a Dakota Digital SGI-5 unit and contact Yuri at Wiring Specialties...he will point you in the right direction.

http://www.dakotadigital.com/index.c...roduct_id=126/

Nissan LS240

iTrader: (1)

or do what I did and use a gps heads up display spedometer

2muchboostNY

iTrader: (8)

^^^^That is the ideal solution....but on a budget the SGi-5

Nissan LS240

iTrader: (1)

the gps hud spedo was only 150 on amazon,

2muchboostNY

iTrader: (8)

Huh.......never saw them for the price. There ya go

novaragtop

Well I ended up getting the DD SG-1, and with a little playing around, now have a working speedometer.
The HUD unit is reasonably priced, but I wanted my Odometer to work as well, for maintenance work like oil changes.
I was in contact with Dakota Digital "TECH" department, and got no usefull info from him as how to set it up. There are a couple of posts on here that were more helpful.
Thanks to all who contributed!!

FlatBlack

Just got done wiring up my speedo using the EKwang writeup and my speedo works which is awesome. I was also really confused by the "build this" instruction on that site since I don't know anything about wiring schematics. His HPTuners Speedo settings worked for my car, although the speed is off from my GPS speed by about ~2 MPH due to my tire differences (I'm running a 275/40/18 RE71R).

Buy/find a 1uf Capacitor and a 22k Ohm resistor. Wire the Positive side of the capacitor (should be the long leg) to the LS1 speedo gauge output (it was Pin 50 - the Green/White wire - on my L33 ECU), and wire the Negative side (should be marked on the capacitor wrapping, and it's usually the short leg) of the capacitor to the Yellow/Lavender ("Y/L" in the schematics - it's the yellow wire with a light blue stripe). The Resistor will "T" off of the negative side of the capacitor and connect to the Yellow/Black ("Y/B" in the schematics) wire coming from the middle connector of the gauge cluster (I "Teed" into the Yellow/Black wire to connect the resistor). I couldn't get to those wires from the under dash connectors, so you'll have to remove your gauge cluster.

The Capacitor and resistor should only cost a few dollars, and considering the Dakota Digital box is $100 or so, this is a much better solution!