Decoding Nissan style Mitsi Electric 360 slot cam sensors

[SleepyKeys]

A couple of snap shots of my wheel stimulator at work.

It was very easy to interface with. 12v power, GND and two 2k pull-up resistors(admin was right same as nissan). I could have sworn............

GM PinOut

A(8x) B(360x) C(+12) D(gnd)

[Fred]

Cool :-)

Wow, I can't believe how BIG that CAS is!

Nice scope too, those don't come cheap! What's it worth?

Any chance of a closer up pic from a little higher angle of the drive for the CAS? I'm just curious, but it looks the same as the skyline one from a distance anyway.

Thanks for posting that up! Interesting info.

Admin.

[SleepyKeys]

I know, I think GM kept it big to help prevent cross fire.

Thanks, I got the scope on ebay for $199 a year ago. Not a lick of english on the box or docs, except the software.


This is the dist installed when I built the engine in 2005. You can see the D1dc procharger, but I'm much happier with the turbo setup.

More info can be found here.

http://www.noid.org/~muttvette/opti.html

-sean

[Fred]

Ah, right, I didn't realise that it was a dizzy :-)

[deviousKA]

Generalized...

The nissan ECCS system is completely event driven using this high resolution CAS. The outer slots are on a counter and the inner slots are used to fire interrupts reading and clearing this counter to decipher which cylinder it is currently on.

A seperate micro uses a similar scenario but uses the normalized backside of the inner slot to clear a compare match on the outer slot counter. When the appropriate amount of outer slots are counted, the compare match is fired and used for either injection or ignition output on the current cylinder deciphered by the first micro.

I run the open-ECCS tuning forums (eccs.hybridka.com) and have quite a bit of experience with this system. I have designed a "router board" for the cas which converts single coil output ECCS to c.o.p or wasted spark. I am planning on porting the complete nissan engine management design to my own hardware (ATMEL XMEGA), eventually.

In the mean time the ECCS units are quite well designed, they are the basis of a few "aftermarket" standalone systems such as REYTEC. I have reverse engineered most of the code and have done quite a few mods (launch control, expanded tables, output control, map-based fuel control, etc.), on the Hitachi 6303 and Mitsubishi 7790 based units.

[Fred]

Hi, thanks for the information :-)

Your forum looks very interesting, being a major RB fan, I'll have to keep an eye on it in future when I get back home near some RBs again :-)

Welcome along!

Admin.

[SleepyKeys]

Generalized...

The nissan ECCS system is completely event driven using this high resolution CAS. The outer slots are on a counter and the inner slots are used to fire interrupts reading and clearing this counter to decipher which cylinder it is currently on.

A seperate micro uses a similar scenario but uses the normalized backside of the inner slot to clear a compare match on the outer slot counter. When the appropriate amount of outer slots are counted, the compare match is fired and used for either injection or ignition output on the current cylinder deciphered by the first micro.

This also helps explain how gm got away with using an 8Mhz 68hc11 mcu with their high-res cas setup. Thanks for the detailed information.


-sean

[Fred]

They are great for quick and detailed sync, but they aren't all that high res really. At least, not when used like we will or they do.

Still keen to set this up with a 36 or 60 tooth wheel on the crank for the ultimate in accuracy AND sync :-)

I reckon that could be pretty sweet.

Admin.

[SleepyKeys]

Yup, nothing like having a motor fire up after it only cranks 1/2-3/4 revolution.

[Fred]

Bump

How's progress Sean? I heard you were becoming a full time developer of FreeEMS C code soon?

It will be nice to hear about your 360 tooth experiences as you start to actively get stuff happening.

Admin.