Sunday, 2 February 2014

Electrics and turning over the engine for the first time.

I have managed to complete the electrics for the starting and charging. I managed to get the setup similar to a car OEM setup with alot of safety in the system.

So I removed the high amp fuses from the MR2 these come in a small block so I did not disturb them (or the wiring) and simply used the wires coming off them. This means I have a 120amp from the battery feeding various 80amp / 50amp and 40amp fuses.

At this moment in time I have only concentrated or Ignition and charging so have ignored my secondary board already fitted.

When fitting the 3S-GTE engine the rear engine loom is split in two effectively as the ECU required 3 connections. The engine loom requires no stripping but the other loom also had all the rear lighting wires in it and as Ill be producing my own wiring for that, so it was stripped of the wires.

The number of wires to actually turn the engine over (and hopefully fire it up) is just 6. The image below shows them wired and where the wires came from and what they lead to. the only wire not shown is the very high amp wire direct from battery to starter motor.

So as you can see there are 3 connectors full of wires and only a few required to hopefully run, but don't strip the rest yet there are some other useful wires in there!

After this, all Earths were connected, there are 3 of the engine block / gearbox to the chassis and one in the loom itself. As well as this the fuel pump will require another earth of its own.

At this point various voltmeter tests were done to check the obvious connections.

At this point I unplugged the fuel pump as there is no fuel in there and gave the engine its first crank over

Success...Wont lie, I was pretty happy with myself. Before 3 weeks ago I didn't know what a relay was, how the wiring was done on a car, or what amps mean't and as for a wiring diagram it was just a nice set of lines. I couldn't of completed this though without the PDF file for the MR2 wiring (in colour) as I have had to learn it to some detail.

The next stage is to complete the intercooler piping, once complete I will do a test start up of the engine. Based on how the relays appear to be in series the fact it turned over should mean it will run...however we will have to wait and see.

If that's all successful Ill complete the coolant system overflow and fill it up to leave it running. To be clear the engine is full of oil, Running without coolant for 30seconds wont cause issues...No oil and 30seconds running could be all you'll ever get from that engine!

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