Update: The optical CAS is crap. I couldn't get an RPM signal from it no matter what. Tried my luck with the spare magnetic CAS I had, and guess what: RPM! I removed the optical CAS from my engine today and I'll be fitting the magnetic tomorrow. Stay tuned folks, its almost there!

 

Optical CAS's are from early miata/Roadster/MX5's weren't they? then Magnetic when the 1.8 was introduced?

Glad you've solved the issue though, nice one! I'm dreading when I run into problems!

 

Yes, 90-93, 1.6 only. The magnetic I have is from a '96 1.8 - this is one obviously suited for my car as it's natural location is on the exhaust cam (the optical is supposed to be on the intake cam).

 

I'd just say that there is something wrong with the optical CAS.
My old optical CAS from the 1.6 works just fine on my 99 engine.

Oh, and it doesn't matter at all which cam the CAS runs from as they both run from the same timing belt. The factory changed the positioning of the CAS when they introduced the 1.8 as they moved it from the intake cam to the exhaust cam. No big deal and certainly nothing 'un-natural' about it.

 

The exhaust side cam may be a bit hotter (not really) and the optical unit may not like the extra heat (not likely), but anywho, it works so...

Did I say that I installed it today and I have RPM?
Now all I need to do is find a decent location for my external MAP sensor:

 

Just wondering, why are you using an external MAP sensor?

 

Wires would be easier to run than a vac line, I might steal your idea! Can always re-use the onboard MAP as a baro correction one.

 

My 96 OBDII Miata didn`t care if the injectors were connected or not when I was running MS. No CEL what so ever.

Dumb PC.... to our benefits of course

REALLY nice setup you have there reverant!!!

 

Right on the money there! Just two more wires (+5Vref, signal - ground is common with the CAS) and you save yourself from routing vaccum hoses through the engine bay and the firewall.

I already do that - this is only possible because my main MAP sensor is 115kPa, just like the stock baro sensor (this is mentioned in the MSnSe documentation).

 

 

Why's routing 2 wires easier than routing one vac line? they all have to go from the engine to the MS don't they?

 

<mr_burns>

eeeexcelent

</mr_burns>

 

They are thinner, they bend easier and they don't leak as easily.

 

'grats... now the fun part.

 

LOL fair enough!

 

Update: I found a small vaccum hose which fitted the MAP's niplle very well. Unfortunately the nipple on the intake manifold has a different (smaller) diameter so the hose won't fit very well. That is why I see about 55kPa at idle. The engine idles very well - although very rich because of the high MAP reading. There is some (tiny) hesitation when stepping on the throttle (I haven't touched enrichments yet) but that will be certainly sorted out. So today was the actual first day of my MS'ed 2002 Miata.

 

Try clamping the hose with a small tywrap.

 

I already have done so, I'll get a proper hose this afternoon.

 

With a proper hose, the idle MAP reading is 36kPa with the A/C off. What do you N/A guys get at idle?

 

28

then again, it reads 96kpa atmospheric. so 33-34.