Install a speedo corrector kit VN/VP

[immortality]

for those that are running shorter diff ratios or have fitted larger wheels and the speedo is reading a little faster (or sometimes a lot depending on gears used) here is a simple way to fix this problem

parts required:
speedo corrector kit available from Jaycar for about $60 pic 1
UB3 jiffy box, $4.50 approx from jaycar
heatshrink
some sort of cold beverage

tools required:
soldering iron
cutters
fine screw driver
wire stripper
a little patience

time:
3-4hrs to complete job depending on how good/familiar you are at electrical/electronics/wiring

assemble the kit as per instructions supplied with the kit, these instructions are very detailed, give a full breakdown of all the parts and how to identify them if your not familiar with electrical components. i recomend using a quality soldering iron with controlled temperature, the cheapy 25w irons just lack a little heat to solder things quickly. i recomend starting to assemble form either the center of the PCB or one end and work your way out as some of the components are quiet close and you don't want to solder a link accross the different tracks on the PCB.

I've tinned the end of each of the 4 wires supplied in the kit and then wrapped approx half in black tape like a regular wiring loom. pic 2

once the kit is complete it's time to fit it in the car

first you need to remove the center console and facia around the stereo, now most of you should be familair with this as i'm guessing most will have installed there own stereo gear, for those that haven't.

1. you need to lift the cover over the gear selector and move it as far down as possible. for a manual gearbox, simply unscrew the gear selector know and lift entire cover off and hang out the way in the passanger footwell. for an auto, disconnect the wiring from the bottom of the siggy lighter and move shifter into the 1 position.

2. remove the 3 screws at the bottom of the center facia and gently pull it away from around the stereo and aircon controls. it should like something like this - pic 3

now you need to free the wiring loom thats under the console and find the wire that we need to cut and splice the speedo corrector kit into. the wire we are after is purple with a white trace. i have unplugged the loom and unwrapped the loom about 200mm. pic 4

to confirm this was the wire coming from the sender unit on the gearbox i simply removed the pin for this wire from the plug, connected the loom back together and went for a quick spin, no speedo confirmed that i had the right wire. assume that i'm a complete mug at this time and check it for yourself

choose a location for your speedo corrector. i have chosen to mount mine by the fuse panel. i intend to get some velcro backed tape so that it will not move about when driving. with the vecro and extended wiring loom that i have allowed for if in the future i need to adjust my setting i will be able to drop the fuse panel cover down, remove box from velcro and get into the box without needing to get my head under the steering wheel. makes it easy to have a passenger make adjustments whilst you drive also. pic 5

pull the 2 wires through to the exsisting loom we are going to splice into. make sure the wire coming from the sender goes to input side of the speedo corrector kit and output goes to the speedo etc. twist wires together and solder together (don't forget to slip heat shrink over the wires first). it should look something like this. pic 6

tape loom up and plug loom back in. put back in orignal position under console. refit facia and gear selector covers etc

find a good eath point and wire +12volts from an iginition switched source.

now it's time to calibrate the speedo corrector kit. again the kit instructions cover this in detail

1. set S1 to 2
2. set S2 to A
3. install LK2 (link, marked on PCB)
4. drive car, speedo won't work (this is normal, i only had to back about 25m in my driveway for this part)
5. LED should flash at 1hz (once per second when it's self calibrated for the incoming signal)
6. set S1 to 0
7. set S2 to 0
8. intall LK3 (link ,marked on PCB, this is the setting i have used)

the speedo should now read as it did before installing the speedo corrector kit was fitted. now you can use S1 & S2 to select correction required. S1 for single units, S2 for tens

to calculate the % difference between you original gears (3.08) and new gears ( i have 3.45) use this simple formula

old ratio/new ratiox100 or 3.08/3.45x100=89.3%

so the old ratio is reading @ 89.3% of the new ratio or 100-89.3=10.7% correction.

i've set mine to 10% (S2 to 1) and over a 5km odo test my odo was less then 300 meters out so it's fairly close (this also shows that holden calibrates there speedo's to read slightly faster then your actually travelling)

if you wish to make an adjustment for different tyre sizes go to this website

TYRESAVE: Tyre Speed Ratings

and use there tyre size calculator (at bottom of there page)to work out the difference between your old tyres and new ones (it gives a % difference as well as actaull size in mm)

final calibration instructions taken inpart from speedo corrector kit instructions - jaycar

[immortality]

i've had a few PM's regarding the speedo wiring on different model commodores, so to clarify a few issues.

On VN/VP commodores it's wired:

speed sensor to dash speedo to ecu

from VR onwards because of the new electronic transmissions 4l60e ( it requires a speed signal and they also used a different speed sensor, i think) they changed the wiring slightly and is now wired:

speed sensor to ecu to dash speedo

so for later model cars you want to fit the speed corrector kit after the ecu so that you maintain the correct transmission shift points etc

for those enquiring about wiring colours etc, please check here Rob's Creative Calibrations - Wiring Diagrams for model specific wiring diagrams, thanks to Doctor Bob

[vp_exec]

Fantastic info - I had heard Jaycar did a kit and this information helps big time. Thanks for the effort.

VP_Exec

[calais_8]

can these kits be brought assembled ready to fit

[Wagon_Wheel]

Hmmm... so before the ECU ey.... will it still be the purple wire with white trace?
Need to know asap so if anyone could help me out, cheers

Edit: Just found a purple wire with white trace connected to the computer, disconnected that and took it for a drive and speedo still worked fine! ???
Need to know which wire i need to use for the corrector unit
Edit2: Reading that VSV8 wiring diagram, looks like the wire is Pink/Blue so will try that

[immortality]

Hmmm... so before the ECU ey.... will it still be the purple wire with white trace?
Need to know asap so if anyone could help me out, cheers

Edit: Just found a purple wire with white trace connected to the computer, disconnected that and took it for a drive and speedo still worked fine! ???
Need to know which wire i need to use for the corrector unit
Edit2: Reading that VSV8 wiring diagram, looks like the wire is Pink/Blue so will try that

sorry mate, didn't see this. best i can suggest is checking the wiring diagrams on the web site linked above

[padrickz88]

so this would make the odo correct on the level 3 cluster aswell? need one now with the 3.9's lol

[immortality]

so this would make the odo correct on the level 3 cluster aswell? need one now with the 3.9's lol

should work fine

[Blair_355]

I just tried hooking this up as you described and it isn't working

[Wagon_Wheel]

Well i had an attempt today at finaly fixing my speedo.
And read over the wiring diagram again and still no luck.
Has anyone had any luck finding the right wire with a VS V8 Manual????

[crewsy]

Well i had an attempt today at finaly fixing my speedo.
And read over the wiring diagram again and still no luck.
Has anyone had any luck finding the right wire with a VS V8 Manual????

yeh mate I did it a couple of months ago. not as easy as the autos. ours have the violet/white wire running from the ecu and then it splices off at another loom probably about a foot away from the ecu behind the glove box. you need to get to that loom and cut the wire running towards the dash, it looks pretty obvious once you've pulled the glove box out. here is a link to the info I used.
Jaycar speedo corrector installation, need definitive answers!

[Wagon_Wheel]

Thanks mate, ill take another look. So follow the violet/white wire from the ecu to another loom?? behind the glovebox???

[crewsy]

yeh thats right. follow the violet/white wire from the ecu up behind the dash and it goes into another loom. that loom has the signal coming one way from the sensor and runs to the ecu (the one you followed up), and then the wire also splices off that loom which runs the signal to the dash as well. hope that makes sense!

[Wagon_Wheel]

Sounds confusing... ill have to take another look at it.

[crewsy]

sorry maybe im just making it sound complicated. when u pull the glove box out and see it, you'll understand and it wont look so bad haha. let me know how you go!

[Wagon_Wheel]

Found it straight away when i took the glovebox out thanks heaps for that mate.

But now i have a problem.... its the right wire and all. So i plugged the gadget in and was ready to set it up... this is what happened...

I set S1 to 2
S2 to A
installed LK2
Drove the car, it recognised the signal and the led was flashing when i was driving.

Set S2 to 0
Set S1 to 0

This is where speedo should return to normal, by trying LK3 LK4 or LK5.... but none of those do anything, speedo still doesnt work?!?!

PLEASE HELP ME~!~!

[Wagon_Wheel]

Bump, anyone?

[crewsy]

all i remember is LK1 LK2 need to be on to be able to calibrate it... other than that I don't know much coz I had my mate (betts on here) doing it while I was driving.. ask him coz he may be able to give you a bit more info into getting the settings right on it.

[Wagon_Wheel]

GRRRR why cant anything work like the instructions say....

Do i need to take any of the pins off completly at all? Or they just have to be set to LK 1 orr 2 AND LK 3, 4 or 5?

[padrickz88]

Found it straight away when i took the glovebox out thanks heaps for that mate.

But now i have a problem.... its the right wire and all. So i plugged the gadget in and was ready to set it up... this is what happened...

I set S1 to 2
S2 to A
installed LK2
Drove the car, it recognised the signal and the led was flashing when i was driving.

Set S2 to 0
Set S1 to 0

This is where speedo should return to normal, by trying LK3 LK4 or LK5.... but none of those do anything, speedo still doesnt work?!?!

PLEASE HELP ME~!~!

I just installed mine and works fine....... have mine on LK2 and LK3 and works perfectly
(at the beginning i didn't have both of them on, took it off lk2 and put it on lk3 then was wondering wtf was going on...... then realised i needed both, im such a noob sometimes lol)

[lowvpcal]

heres a brain tickler for yall. i have recently (finally) finished replacing my vp calais loom with a vr one so i can use a vs statesman interior. everything works except the speedo who knows how to get this to work? the engine loom, computer, auto trans and engine are all vp the body loom, climate control loom and headlight looms are all vr

[delcowizzid]

vp the speedo comes up through the floor to the dash then from dash to ecu .vr goes to ecu and tees off to dash .the plug to the ecu loom from the body loom under the dash may need rewired to suit then the speedo will be fine but the ecu is going to spit the dummy at geting the wrong pulses i bet you hit the speed cut early as

[lowvpcal]

i havent done any of those things as yet i have removed the trans loom thinking id be able to splice them together but not so much. i know of a few ppl on this forum who have done the same thing but they didnt really explain clearly or that well (pics are a big massive help). apparently theres a couple wires i have to run from the trans loom in the floor to the ecu but buggered if i know which ones or to where on the ecu

[lowvpcal]

noone knows?

[lowvpcal]

noone at all