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Michael Pauling

Wiring a G4 Extreme to suit Mitsi Legnum?

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Hi all, I am just working through the process of wiring an extreme to replace the ecu in my 1998 Legnum VR4 and have a few questions i would love a hand with.. I have the wiring diagrams for my car, and have been working thorugh it with the information on here for the Evo 4 plug in stuff, as the ecus and pinouts are similar, i am making a loom adaptor from the factory ecu plugs. A few things i havent been able to get my head around as yet are: 1) Alternator. The factory ecu in my car is connected by two wires to the voltage regulator. If i am removing the factory ecu do i need to configure the link to read the voltage and output a signal to the alternator? I dont quite understand what the ecu is doing in that respect.. 2) Ignitors. I am assuming that since i am making a loom adaptor i wont be needing to add an aftermarket ignitor pack? Or is are the ignitors built into a factory ecu? 3) Knock, Crank and Cam sensors. Is it acceptable to wire these to the factory harness? There is a sensor ground as well as the various sensor wires in the pinouts, but i am not sure if it is better to try and run the premade loom from the link instead? Dont want to cut any corners, but a lot of the engine bay has to come apart to get to some of the sensors :) 4) Base map / initial start. I am assuming there is no base map available for the 6A13, however through the Evoscan diagnostic stuff i have got copies of some of the fuel trim stuff from the factory computer. Is it possible to turn this into a base map? Or am i better off taking it to a tuner and leaving all the inital stuff to them? This is all pretty new to me, so any advice or other things i should be looking at would be great! Thanks, Michael.

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A1) The alternator in tha factory application might have been controlled to avoid the engine dropping in RPM when a large electrical load is switched on.  You shold be fine and not worry about this input.

A2) There will be factory ignitors either built into the coils or as an external ignitor pack. So as long as you retain the factory wiring you will be fine on this also.

A3) For the wiring of the crank cam sensors etc the factory looming will be up to the task. 

A4) As long as you configure all the outs and ins correctly you will be able to get the engine to run / idle reletivly quickly. But if in doubt  then letting the tuner do it all is a very good idea.

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Awesome, thanks for the help! Iv got a (hopefully) decent looking loom adaptor on my bench now.. One other question if i could trouble you please.. With the factory ecu there are two main ground wires, sensor ground (Pin26 and injector ground Pin13) As far as i can tell from the wiring diagrams i am looking at they both are connected in places, and go back to the main earthing points, which confused me a little bit.. Is it okay for me to use these to ground the Link Ecu? or should i be connecting the sensor ground pin to one of the green sensor grounds on the link if i am thinking of using the factory loom for knock and angle sensors? Thanks again for the reply, iv been teaching myself as i go for a few months now, and i think its 99% ready for a test soon :)

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Those earths will be fine to use as grounds for the ECU. The important bit is that the sensors are grounded through the ECU rather than direct to the block. This is to keep the sensor grounds at the same potential as the ECU ground.

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Hi guys, iv picked up on this again after a bit of a break.. I am having issues with the main power wiring.. I thought by using a loom adaptor i would be able to use the pinouts, but i seem to have misunderstood some principle with the main power. I wired the link power supplies to pins 25 & 12, which i thought were the 'on' position power sources from the key. I also wired the engine control relay, pin 38 to an auxiliary output (injector 7), as i thought this would be used for the power hold? All that happened when i tried to connect to the link for the first time, was the engine control relay buzzing on and off, and the link not starting properly.. I put a volt meter across the various bits, and it seems like the engine control relay to the factory ecu (pin 38) is 12v constant, which i guess means the relay is connected all the time at the moment, and pins 12 & 25 only seem to supply 2-3volts at present (link unplugged) Am i missing something here? Do i need to make pin 38 the main power supply to the link, and use pins 12 / 25 for an aux? I have found that most of the car relates fairly close to the evo link info, if that helps anyone shed some light.. Any help would be much appreciated :)

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Hi Michael,

First off you've wired everything correctly. Pin 38 is the other side of the relay's coil so won't provide enough power for the ECU. The ECU needs to switch this to ground to turn itself on (and hold itself on, ECU hold power).

The only problem with this is the ECU needs to power up first in order to to do this. Check out ECU hold power wiring on page 19 of the G4 Instal Manual: http://www.linkecu.com/support/documentation/g4-engine-management-documentation/G4Install

You will need to add the 1n4007 diode as shown, and connect a DI to an ignition source.

This issue aside you seem to have something backfeeding that is trying to power up the ECU. Have a read through http://www.linkecu.com/support/documentation/technical-notes/preventing-auxiliary-channel-backfeeding.pdf to see if you can sort it out.

Good Luck

-Cameron

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Michael,

Sorry for the late reply, this thread seemed to have slipped past me. How did you get on?

I doubt you've done any damage. Do you have an IGN source going to DI2? Is it configured and Ignition Switch? Do you have the output that's connected to pin 38 setup as ECU hold power? Which output is it?

-Cameron

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Hi Dan

I've got a G4+ on my VR4 engined Ford Anglia, and briefly played with one one in an auto Legnum too.

I'm using a slightly modified Evo 1-3 plugin. I'd strongly recommend getting a Wire-In version of the ECU, rather than one of the plug-in versions. It gives you much more flexibility for wiring and features to use, at the slight expense of having to do a little custom wiring changes.

One question... Do you have an auto or manual gearbox? One thing I'd not got round to figuring out before I moved on was the torque reduction signal from the auto ECU, which reduces power output during gearshifts. This will be important for longevity of the gearbox, but if course not applicable for a manual!

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