Category Archives: Engine Control Unit

3SGTE Mk2 MR2 Turbo Lambda/Oxygen Sensor Part Number

I had real trouble finding a suitable alternative oxygen/lambda probe for my 1992 Rev 2 MR2 Turbo. I can’t find the original Denso part number at the moment, but I managed to find that a Denso DOX-0107 fits the flange size correctly and is 1-wire, it just requires soldering to the original connector. It’s got a Flange 44 type flange which apparently matches the 3SGTE.

I got it from http://service-parts.co.uk/denso-oxygen-sensor-dox-0107

Rover Mini MPi Inlet Manifold and Throttle Body

I’m embarking on a project to fuel inject my 1987 Austin Mini, which has already had an engine swap from a 998 to a 1098, but currently runs on an HS4 1.5″ single carburettor.

This obviously offers a reasonable level of tunability, with the ability to change needles, dashpot damper springs, dashpot oil and mixture adjustment and is relatively easy to set up for quite a reasonable state of tune, especially now that I have an AFR meter installed.

However, I would like to try fitting an MPI system and develop my own ECU for electronic fuel injection. Due to the ‘Siamese ports’ on the A-Series engine causing charge robbing, and only having one fuel injector per two ports, this is apparently something that’s difficult to achieve well, which makes me want to do it all the more.

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What does a Manifold Absolute Pressure (MAP) sensor do?

Manifold Absolute Pressure (MAP)/ Manifold Pressure sensors are used to determine the pressure of the air inside the inlet manifold, just before it enters the engine inlet ports. This is generally measured between the Throttle Body and the intake ports on a naturally aspirated engine, and between the turbocharger compressor outlet (after the Intercooler) on turbocharged or supercharged engines.

GM Manifold Absolute Pressure sensor

GM/Bosch Manifold Absolute Pressure sensor

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Arduino ECU By Brenamanf

I was sent a link to this website by the author, who appears to have created an Arduino ECU for spark control. Although the details are a little sparse, It appears that he has developed a lot of the required hardware himself. It looks like the main controller is an Arduino Nano and utilises Manifold Absolute Pressure (MAP) and a knock sensor to determine the ignition timing on a Peugeot 205 Tu9 45Ch. It would appear that the ECU has been developed over a number of revisions and has been in operation for over a year.

http://brenamanf.wordpress.com/page/2/

Video Explanation

I’ve made a video of the whole system explaining all of the sensors, actuators and interfaces, and some of the more advanced indicating equipment that I’m using.

A more detailed explanation of the closed loop ignition timing control is given here: http://scottsnowden.co.uk/?p=341

Closed Loop Ignition Timing Control

I have been busy over the last few weeks with various things, but have now completed most of the practical work on my project and am now at the stage of writing up the report/dissertation. I have successfully managed to achieve closed loop ignition timing control by using the Stellaris Launchpad development board to directly interface with the optical encoder on the engine and the pressure sensor charge amplifier (this replaces the AVL IndiSet 620 in my system).

ECU in black on left, angle of peak pressure and optical encoder interface on right. Connected together via serial

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Exhaust heat exhanger

In order to run the engine inside, I had to set up an external exhaust to get the fumes outside. This had been done with a big exhaust manifold attached to a flexi rubber marine exhaust hose, and then poked through a hole in the wall. This was ok operating the engine at idle and under low loads, but the rubber hose would get extremely hot under high load high speed conditions. It then began to melt internally and was causing the whole building to smell of burning rubber.

Copper pipe exhaust cooler (not good…)

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