Recalibrating the tacho and speedo after a flat battery
In 2015 an owner jump-started a Turbo that had sat for about a month with a completely dead battery. While the voltage was too low the instruments went wild, with warning lights flashing and the temperature gauge reading 160. After a jump start, everything seemed to work. Then, driving home, the tacho read about 1,100 rpm at idle and the speedo over-read by about 10 mph across the range. The needles were also jumping up too far when the ignition came on.
He found a Lotus service note (the "Electrics" document, page 9) and followed it:
- Leave the driver's door open.
- Hold down the trip reset button.
- Turn on the ignition.
- The needles drop to the bottom and bounce off the stops. Let go of the button when this happens. The display shows the version number and similar.
He said the instruments were then back to factory calibration. Another owner said this saves him disconnecting the battery next time.
Does the driver's door matter?
Owners argued about why the door has to be open, since the wiring diagrams they looked at show no link from the door switch to the cluster. The first owner said he was just following the Lotus note, and it might not be necessary. Later he posted a block diagram for the Turbo (Z20LET) which, he said, shows the driver's door switch connected to the instrument cluster. Another owner said the lights-on buzzer is inside the dash unit and so needs a door switch link, usually the driver's side. A different owner asked whether the passenger door would do, and wasn't answered. So the driver's door is the safe choice.
Taking the instrument pod (stack) out
There are a few partial answers from 2005 and 2011, including TIS instructions for the stack gauges (one owner noted that in those, the steering wheel is only removed to make the pictures clearer). Put together:
- Remove the dash top. See dash top removal.
- Remove the steering column shrouds. From the Elise instructions that one owner posted: the lower shroud is held by three screws at the bottom, and the upper shroud has screws too. On the VX, two of the screws are underneath the steering wheel, so the wheel has to come off first (2005). See steering column shroud and steering wheel removal.
- Unplug the loom connector behind the stack. Be patient and find the latch before you pull it.
- Remove the two large bolts that support the steering column and the binnacle. The binnacle then comes out in one piece.
- Four small nuts or bolts separate the instruments from the binnacle hood. You will see them once it is in your hand.
The first owner only had the Elise instructions and hoped they were the same. Two others then described the VX in the same terms, but nobody posted bolt sizes.
A needle has fallen off (2011)
An owner found one day that the rev counter needle had vanished. His question was whether the speedo could come out without removing the dash, and whether the plastic screen could come off to refit the needle. What he was told:
- The dash cover has to come off before the gauges can be reached, then the steps above.
- The plastic screen is held on by a small amount of adhesive around the edge. One owner's worked loose and fell away on its own, and he put more adhesive on. It tucks in at the bottom, so pull it away at the top and lift it out at the bottom.
- Be careful. One owner said it is fragile, and that if you break the screen, replacement parts aren't available and you would need a whole new pod. (2011. We haven't checked this.)
- The owner who asked was frustrated that one needle takes so much effort.
Retrimming the pod. In 2005 an owner who had the dash off found the binnacle looked glued and asked how people had it retrimmed. He got no reply on that point.