Reverant

iTrader: (10)

I also installed the LM-1 wideband controller. I connected the serial port of the LM-1 to my incarpc, so this is going to be my new office for quite a few days:

timk

Just an idea but maybe you could use the same pins at the MegaSquirt end as this guy:

http://www.dsmtuners.com/forums/show...82#post1862982

Then you can just follow the guide here:

http://www.diyautotune.com/tech_arti...alon_laser.htm

kingofl337

It will be interesting to see how this turns out. I like the LCD screen that looks pretty spiffy.

I notice your speedo is in kph you live in Canada 'A?

Reverant

iTrader: (10)

The LCD touchscreen will be my center of operations once the MS installed, thanks for the kind words. I live in Europe/Greece.

Reverant

iTrader: (10)

Updated the schematic once again. I started fiddling around with the Megasquirt, so I had to change the colours of the wires to be the same as the real wires on the DB37 harness I got.

Note: The harness I got is from RS Autosport, so the colours are propably for that harness only! If you got a harness from an other vendor (ie diyautotune, fuelandspark, etc), your mileage may vary!

I also connected the external GM MAP I got (a 114kPa unit) and tested it (sucked air) and made sure that MS showed the changes in MAP readings. These changes in wiring are also reflected above.

Jim

Reverant

iTrader: (10)

Update: The CAS I got from eBay is propably dead. Or rather, it is certainly dead, or so says my oscilloscope. I borrowed a '90 optical type from a friend (who also bought it for a Megasquirt), and to my surprise, only the inner track works (the cylinder indication for ignition events, i.e. the inner 2 unevenly sized holes). My 3 options now are:
1) Find another CAS that works.
2) Fix the optical type CAS (it is propably servicable)
3) Use the stock crank angle sensor which is (really) mounted on the crank on my 2002 and use the inner track of the optical CAS that works.

I will consider my options and let you guys know.

Jim

Reverant

iTrader: (10)

Update: I managed to fix the optical CAS sensor. One of the wires of the receiving optodiode is cut somewhere in the black plastic disc inside the CAS, so I opened up the housing and the black plastic disc and routed a wire from the diode to the connector of the CAS. Hooked it up to an oscilloscope and both channels (CKP+CMP) show up just lovely. I also updated the diagram above, no fuel pump and no fast idle in this version and the crank + cam sensors have been merged into one unit, as is the actual sensor.

Jim

2004GS

iTrader: (1)

Will the newer magnetic type CAS sensors work just as well?

With a CAS sensor installed controlling fuel and spark must be very similar to the way it is done on the NA's.

Reverant

iTrader: (10)

Yes, the newer magnetic type (Hall effect) CAS (as found on the 94-97 1.8 cars) is electrically compatible with the older, optical type. The output voltage is the same, the timing is the same, the pinouts are also the same, the only thing that changes is the housing, which is different only because the optical type was fitted on the intake cam on the 1.6 cars, not on the exhaust cam, like on the 1.8 cars.

In fact, the magnetic type is preferable to the optical type, it's supposed to provided more robust output pulses thus less spark scatter.

Anywho, with this CAS installed, controlling fuel and spark should be entirely identical to the NA cars.

Reverant

iTrader: (10)

Update: Using a DMM, I got the resistance and the voltage across the ATS and the CTS, so in conjuction with a known graph (R/*C), I am now theoretically able to use the stock air & coolant temp sensors.

The values I got are:
ATS: R2=1550©, Vo=1,82V => Bias Resistance of stock ECU: 2713©
CTS: R2=1330©, Vo=2,31V => Bias Resistance of stock ECU: 1550©

Photos for your viewing pleasure:

kingofl337

How are you going to install the studs to bolt the CAS to? Are the holes already threaded?

Reverant

iTrader: (10)

Yes, there are already threded holes, with bolts that hold the cup in place. By "cup" I mean the thing that is in place of the CAS on the 99+ 1.8 engine, which really is a cup. The only issue is that with the 1.6 CAS, you can only bolt it down using one stud, not two, compared to the 1.8 CAS, but this isn't really an issue.

Reverant

iTrader: (10)

Update: Almost finished my plug and play box:

richyvrlimited

iTrader: (1)

Very nice!! Can I ask how you made it plug and play? Ideally i'd like to do mine that way, I'm going to order all my kit from DIYautotune, and that'lll include the 12' harness, but that's only the DB37 end and bare wires on the other, sooo how've you done yours??

Many thanks in advance

Richard

kingofl337

Its only kinda plug and play in his application because he is using the 94-97 CAS.
Then again I'm not sure you can make the 01+ N/As truely plug and play. The only years I know you can is the 94-97 and the 99-00. The 90-93 can be close but you have to run a wire for the fuel pump and need to add an IAT sensor.

Reverant

iTrader: (10)

It is pnp in that you plug the box between the stock harness and the stock ecu, plug the CAS and the MS and it works. Yes, you still nee the extra CAS.

You can't make the 99-00 pnp either, the cam signal seems incompatible (inverted plus the 180 degrees reset signal is a double inverted peak). So the only "real" pnp candidate seems to be the 94-97...unless you only plan to do fuel injection (not ignition) in which case any 94+ Miata can be a pnp candidate.

Jim

richyvrlimited

iTrader: (1)

cool, that's handy seeing as my car's a 96

But where did he get the plug from for the stock ECU? In my mind to make it plug and play you first need to get a small extension harness for the stock harness, then cut into that leaving the stock harness untouched.

Where can you get an extension harness from?

Reverant

iTrader: (10)

http://www.boomslang.us/
http://www.autosportwiring.com/

Reverant

iTrader: (10)

I've decided to try my luck with the stock ignition system (ignitors + coils) so I'll be leaving out the VB921 that my board has. To that end, I've modified my pnp box: I added 2 more switches to control whether I want spark from the stock ECU or from the MS (the other 4 switches on top are for the injectors).

Mandatory pics:

Reverant

iTrader: (10)

Almost there...