Jaycar Speedo Corrector Kit Issue

[Senator829]

Just got my car back after having some electrical issues fixed but while they were at it had a jaycar kit installed as the car has a 3.47 diff in it. Whilst the speed is now correct ive noticed the needle is jumping intermittently by about 5km/h and was cancelling out the crusie control. The auto would also not kickdown when accelerator floored.

Will take it back tomorrow as I had to go work after I got it home. I quickly checked and it wired into the correct place ie between the ecu and dash and the light on the jaycar unit is flashing when receiving a signal. Any ideas?

 

[_R_J_K_]

Which wire did they hook it into and where?

 

[Senator829]

I will take a pic soon and post it





The black wire running in is from the speedo corrector and he has run it into the grey loom?

 

[Senator829]

Added pics above.

 

[someguy360]

The speedo corrector kit needs to be wired to the ECU, if its just wired to the cluster (which it looks like it is in your pics) it means only the speedo is being calibrated.....you say you have fixed this but it depends which wires you used because none should be going to the cluster, if you have spliced correctly into the ECU the VSS should be sending the correct data to the cluster anyways (if I recall correctly)

By wiring it to the ECU, it fixes the shift points (this drove my nuts on my VS, shift points were complete garbage after gears until I got it corrected and the car drove like a pig), speedo, cruise, trip computer etc.

I'm not 100% sure on which wires for the ECU it needs to be spliced too but I would assume its to do with the VSS wires.....a search or someone else on here might know.

My tuner ended up installing mine near the ECU for easy access to the main wiring looms down there.

I would take it back to them and ask them politely to do the job properly.

 

[Senator829]

I've read conflicting things about where it is to be wired for a vs. most things I've read is after the ecu and to the dash! Even so why would it be fluctuating and why if it's installed after the ecu would it now effect the lack of kick down on the auto?

 

[someguy360]

Most tuners/auto electricians I speak to say the only way to do it properly is to wire before the ECU.....otherwise the shift points will be out etc....it won't be reading accurately if after the ECU.

You can wire it after the ECU no problems, but it will only affect the speedo then, not the rest of the electrical system that requires speed data such as the transmission, trip computer etc

The fluctuating I can't explain.....earth maybe?

 

[Senator829]

I will take it for more of a drive tomorrow before I take it back to them. Thx for the advice

 

[Tasmaniak]

Most tuners/auto electricians I speak to say the only way to do it properly is to wire before the ECU.....otherwise the shift points will be out etc....it won't be reading accurately if after the ECU.

You can wire it after the ECU no problems, but it will only affect the speedo then, not the rest of the electrical system that requires speed data such as the transmission, trip computer etc

The fluctuating I can't explain.....earth maybe?

Exactly.

From output on gearbox to ECU and somewhere in between. Anywhere else is kind of pointless.

 

[Senator829]

Hey Guys this is where Id read about it being wired at the dash before in this thread

https://forums.justcommodores.com.au/threads/install-speedo-corrector-kit-vn-vp.60651

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

Seems to be conflicting info on the matter all over the place. Sorry to be a pain just trying to make sure I get it right. Im still confused as why the auto kickdown has changed if its been wired after the ecu??