Chris Williams' Journal

Went to Docs and gym this morning and when I came home I was sitting in the car and started thinking about and looking at the two gauges in front of me.

Next thing I know I'm sitting there with the tacho in my hands and thinking 'well that was easy'.

Popped off the bezel and the glass - again easy! Then pondered on how the innards came out. Took it inside and used a kitchen knife to pry out the surround with the rubber in it and could see that only 2 screws where holding the guts in there.

Screwdriver made short work of that and I'm studying the innards. Don't think I'd had this apart before.


Well the trim pot is very obvious, it's that black thing at the top:


It looked like it would be easy to hook the innards back up in the car and attempt to adjust with the other gauge as a control. When I first hooked it back up it wouldn't work! Then it dawned on me that it needed an earth. So I found a short lead with an eye on it and attached it to one of the screws that I'd removed to take the innards out. That's the green wire here:


The engine analyser was attached to the motor and sat just in front of the windscreen:


Then with a screwdriver while juggling the throttle to get steady revs via the analyser, I was able to adjust the trimpot to match the tachos reading to the analysers:


Pretty easy actually and I checked it at a few different readings 1000, 2000 and briefly at 4000.

Put the tacho back together carefully and thought about the speedo.

Decided to take it out and have a go at that. Long story short - couldn't remember how it came apart because of the trip meter stalk.
Well, I posed the question on the forum but because of the time difference of most of the members, got no answer. So had a brain snap and wound the needle around and hooked it over the stop again. Bone head move as it turns out because now there way too much tension on the needle and it won't move at all on a test run.
I also had the devil of a time getting it back in - tacho went in reasonably easily. Still a bugger but the speedo is a real turd!

Anyway this evening after a failed test run on speedo (tacho appears to work well) I checked the forum post and did some extensive searches and it appears that the needle and the face of the gauge has to come off. I don't remember having to do that - but I must've.
Anyway that's the plan. I may be able to do it without removing the gauge completely. If I undo what I did today with the needle I may be able to take the needle off, run it with a temporary needle made from a small piece of masking tape and take note of where it is pointing at , say 70kph using the GPS and then come home and work out where the needle needs to go accordingly.

We'll see tomorrow. Stay tuned.