Aaron's Custom ST16x Econometer

Have you considered your IR thermometer might need calibration? They aren't all that accurate in the first place and different materials will give different readings at the same temperature.
Not sure how much current the heating element uses, I'll check. Leaving it on while the key is on should be fine though, I just have an OCD thing about wasting energy. Everything I design uses the least amount of energy as possible.

Setting the fans always live would be fairly simple, I'll take a look at the diagrams for you tomorrow. I don't think it's required though, Toyota did have a bunch of engineers working on the Celica

aaron.

 

Couldn't get a good reading on the heating element, but it would be a negligible amount of current draw. You could hook the heater up to the main relay and it should work just fine.

For the fan working independent of the ignition, buying an extra relay, wiring it up to the temp switch above the thermostat and having it switch either +12v or GND for the fan would be the safest way.

As always, I'd be happy to draw you up a schematic if it's needed.

aaron.

 

That would definitely work.
Bypass the main EFI relay, connecting the fan relay directly to +12v, just make sure you fuse it.

aaron.

 

What is this, a sparky competition? :tongue:

aaron.

 

Pretty sure the aircon fan is triggered by the aircon being turned on.
You could add a secondary connection onto the aircon fan to make it run when the radiator fan is running if you wanted to.

Basic physics says that your engine can't heat up more after it's turned off

aaron.

 

The A/C fan circuit has a horrible schematic in my repair/rebuild book, so I'm not entirely sure what controls the fan.

I'm sure Toyota had a reason to have the fans not work with the ignition switch off, as odd an idea it is.

I only have one fan in my celi, I don't think the aircon fan cleared my exhaust header when it was installed. This might be why my aircon doesn't work, or it could just need regassing.

aaron.

 

It could be an option, but it would take up an extra input/output pin and lots of extra wiring. I could build a separate adjustable fan timer that doesn't keep the engine running and can be put in the engine bay for about $5 easier.

EDIT: Actually, it would be quite simple to have the option in the econometer. If you don't mind only having space for 4 extra gauges instead of 5.

aaron.

 

Just a small update.
I've built a rough prototype just using parts that I had on hand, so now it's much more portable and I can test and debug it in my car.

The buttons also work a lot better now, which makes testing the menus a lot easier.


P1030319 by DeL337--, on Flickr


P1030322 by DeL337--, on Flickr

The mess of wires behind it
Of course the finished product will be a lot prettier.

aaron.

 

Thanks It feels great that more people than just me are excited about something that I'm building for once

I took the fuel tracking functions for a test drive this morning, turns out there is about half an inch of throttle movement between 0.08 mL/minute and 0.20mL/minute! This thing will really help me and everyone else save heaps of fuel.

I'm actually contemplating including an LED fuel usage indicator to install in the gauge cluster for quick economy reference, I know it will be useful for me and quicker than reading numbers.

aaron.