Tachno shows 11000rpm while PFC shows 0 rpm?

[leung23c]

Hi guys got weird stuff happens. I took my cluster out, swap light bulb and put it back on. As soon as I turn on the ignition (but not start the car) the tachno instantly rev to max rpm (11000rpm) and stay there. I check PFC with controller which shows the correct 0 rpm. I have been splicing and soldering wires going to ecu loom to install boost controller. But after I plug back the avc-r everything came back to normal, for now... Any suggestion where to inspect? First time ever it does it

[Skym]

The rpm signal goes from CAS to ECU to dash. I would suspect there was a wiring problem from ECU plug to dash if ECU showed 0 rpm. Possibly a earthing problem (earthing activates devices).

[leung23c]

Thanks for the info!

[MattiasJacobs]

Do a good pull up to 6-7000 rpm and it might bounce back. Mine will jump and stick on startup sometimes

[leung23c]

http://www.youtube.com/watch?v=1C9CZL4Thus

Here...funny tachno...pissing me off

[Skym]

Possibly there could something earthed to same earth as 3 on ignition barrel???? It can happen with Apexi auto turbo timers and cause turbo timer when on auto turbo timer feature to shut engine off when turn to 3 on ignition barrel, damage turbo timer (has to be replaced). They mention 2x different ways to earth turbo timer (I think was direct to chassis or earth off ECU earth) based on what features you use on turbo timer.

[leung23c]

Umm there is a turbo timer installed long before all this happen and I didn't touch the wiring and it functions fine. But yeah I was earthing a number of devices like aem uego. Any hint on checking ignition barrel ground? I am right at it but it looks a complete mess. I also read some stuff on gtroc about the cluster harness being dodgy and need some cleaning and gently prying.

[Skym]

Wiring is not my forte. But earthing incorrectly sounds like the cause.

Sometimes the wires are pulled out of plugs if the wiring is pulled on accidentally instead of the plug.

Consult wiring diagram in back of manual for model of Skyline, as tells you the colour of wire (from what I can remember when looking at a S chassis manual, for example it was Y/B next to line for Yellow / Black), shows where it goes to, etc.