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Any questions you have before you begin buying, building and installing.
By wvdschel
Hi guys,

First off - this is a learning experience for me, I'm trying to learn about how cars and engines work by modernizing my 1990 Toyota MR2 with a bone-stock 3S-GE in it. I don't know a lot about this stuff and have close to 0 practical experience.

Currently I plan to modify it in two stages, and am looking for advice for the first stage now:

Stage 1: Modernize the engine management

Currently the four cylinder engine is using a mechanical flap to measure intake volume, and a single coil/distributor based timing and ignition system.

My intent is obviously to put in a Speeduino based ECU, upgrade to coil-on-plug with sequential ignition, and remove the old bulky and probably faulty air sensor in favor of a temperature sensor. I'd also like to replace the old loom with something home-made, so I can keep all the original bits around in case I need to revert everything at some point. I'm looking for advice on what to buy for this step, and how to plan and execute this part.

I need the car to be road legal, so all the indicators, lights, wipers, defoggers, ... need to work. Some of these are routed through the ECU. If needed, I can keep the old ECU around for these functions, but it would be nice to have just one loom and one ECU.

Stage 2: Forced induction

Once the engine is running fine under the new management, I want to try and add a cheap supercharger (I have one from a similarly sized & powered Mercedes SLK I got for 90 euros), and learn how to tune the ECU for making more power under boost. My goals here are very modest, I mostly want better low end torque. This step is just dreaming on my part for now, but might be useful to keep in mind. I might need to upgrade the fuel injectors & fuel pump for this part.
By wvdschel
So I'll elaborate a little bit on my ideas for the ignition & timing part. I'd like to keep things cheap, so I figure I'll just buy some used Yaris or Auris coils, and have a metal plate cut I can use to mount them to the rocker cover.

For timing, I'd like to entirely remove the distributor. I guess I'll have to seal up the opening somehow - would something like JB weld or some other epoxy based binding be strong enough?

So I would need to add a trigger wheel for the crank- and camshafts, and some sensors to go with them. My guess is that the camshaft trigger wheel goes on the intake camshaft, but I haven't found anything in the documentation or elsewhere about that yet. Can I get universal/generic parts for these wheels, or do these need to be specifically designed for the engine?
By stum
Hi. once you have read the WIKI a few time and start to get familiar with speeduino you will relise your choices are plentiful.

You can start with a off the shelf board like sold in the Speeduino store. Which is how I have gone. or there are number of other sellers, built boards or build it your self's

I too have a Toyota engine, and if you search up 3vz-fe you will see my build and how I went about it.

There are are a number of other Toyota builds on this forum, search and read them will give you an idea.

good luck
By JHolland
wvdschel wrote:
Fri Nov 06, 2020 2:03 pm
I need the car to be road legal, so all the indicators, lights, wipers, defoggers, ... need to work. Some of these are routed through the ECU.
Are they really routed through the ECU? I would expect them to be inputs to the ECU to help control idle with varying electrical loads.
By SuperGripM
As JHolland said, your ECU will take state values from those to compensate idle speeds. It doesn't control them.

I'm doing a similar job on my 7M-GTE, which uses a very very similar Denso ECU, except it runs one less ignition and injection channels, and an extra knock input.

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