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Atessa has nothing to do with the engines ECU. The 4WD has it's own ECU.

I wouldn't question why you'd like to bother with the Autronic ;)

Marc
 

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Discussion Starter #3
Atessa has nothing to do with the engines ECU. The 4WD has it's own ECU.

I wouldn't question why you'd like to bother with the Autronic ;)

Marc
Ok.
I had Autronic on my Cosworth and I was very satisfied with that.
And I can trow out alot of wiring loom:p
Anyway. I have to know what I have to keep.
Havent started taking it apart yet,but I guess the wiring for the atessa system is blended with everything else.
 

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Atessa has nothing to do with the engines ECU. The 4WD has it's own ECU.
Marc
Wrong.
The Atessa ECU need to communicate with the engine ECU.

Autronic is FAR FAR better ecu then most on the market that are plug`n`play for skyline.
The best thing about it is, it uses a cranktrigger for crank position, and not the CAS.

Asim
 

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Although the engine and 4wd ecus are separate, there are shared sensors between them. Now I read that on some aftermarket ecu setups the shared sensor's voltage is reduced by the aftermarket ecu, which isn't a problem on stock ecus.
This causes the 4wd ecu to go into rwd only mode.

I can't remeber how to fix it specifically, but if you try PMing dirtgarage on SAU, he sorted the issue for his vipec ecu
 

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Discussion Starter #6
Wrong.
The Atessa ECU need to communicate with the engine ECU.

Autronic is FAR FAR better ecu then most on the market that are plug`n`play for skyline.
The best thing about it is, it uses a cranktrigger for crank position, and not the CAS.

Asim
Just tried to call you. Got your number from Lars:)
 

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Although the engine and 4wd ecus are separate, there are shared sensors between them. Now I read that on some aftermarket ecu setups the shared sensor's voltage is reduced by the aftermarket ecu, which isn't a problem on stock ecus.
This causes the 4wd ecu to go into rwd only mode.

I can't remeber how to fix it specifically, but if you try PMing dirtgarage on SAU, he sorted the issue for his vipec ecu
He must have done something very wrong.
I have put Autronic, Electromotive Tec2 (old old old ECU), Electromotive TecGT (in my car now), Motec M800, and every time i have hooked it up the way i figured out how to do it, it worked like a dream :)

It not THAT difficult. The atessa ECU only need 3 wires from the engine ECU.

Asim
 

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Attessa TPS feed

The Attessa requires a TPS (Throttle Position Sensor) feed in order for it to function properly and control the 4WD system on the GTR. The factory ECU receives a TPS input feed via pin 38 and gives an output feed to the Attessa via pin 56. If you’re changing the factory ECU to a wire in stand alone ECU such as Autronic you need to run a wire connecting pin 38 to 56 to keep the 4WD working as normal.
 

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Ok, I stand corrected. There seem to be some wires that need dealing with. But as I thought (and remembered), it isn't exactly rocket science.

Most people think that the Atessa is build into the engine ECU, so is removed when you change it for something else. This is wrong and thats what i basically tried to state.

Marc
 

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Aki, where's your information from because my docs read different? Also, there seems to be a difference wether it's a VSpec or not.

Could you post your diagram?

Marc
 

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Discussion Starter #14
Ok, I stand corrected. There seem to be some wires that need dealing with. But as I thought (and remembered), it isn't exactly rocket science.

Most people think that the Atessa is build into the engine ECU, so is removed when you change it for something else. This is wrong and thats what i basically tried to state.

Marc
What part of the wire loom do I have to leave in the car?
Can i Take it all out and just use the wires to the atessa ECU?
 

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What part of the wire loom do I have to leave in the car?
Can i Take it all out and just use the wires to the atessa ECU?
In other cars ive built, we have removed the whole engine loom, abs loom.
You just keep all the wiring for the atessa system, abs sensors, g-sensor, and give the atessa ecu tps + - and rpm.

If youre not completely comfortable with wiring, and electronic diagnostics, it can be a pain in the ass :chairshot

Asim
 

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which autronic is it? i have a sm4 for my 33 gtr and got a custom loom made by mrm racing in sweden,it depends on the version of the sm4 for the 4wd.if its a 109 chip it will work with the stock cas and i think the 4wd will work without any mods.
or if you fit a crank trigger with the autronic cas disc you have to fit a diode on the loom.
try mrm racing guy is called robert
http://www.mrm-racing.se/index.php?pageid=autronic
 

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Discussion Starter #18
In other cars ive built, we have removed the whole engine loom, abs loom.
You just keep all the wiring for the atessa system, abs sensors, g-sensor, and give the atessa ecu tps + - and rpm.

If youre not completely comfortable with wiring, and electronic diagnostics, it can be a pain in the ass :chairshot

Asim

The ABS unit is also removed.. will this affect the 4wd system?
 

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If you are going to use the stock cas, then you might aswell use something like power fc or similar ecu.

Stock cas is not very reliable at higher rpms, ignition timing can drift as much as 10degrees + -

Asim
 
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