I've been doing a bunch of research but still have a few questions related to the Cam Angle Sensors in the NB. But first, some background. This is a bit long winded but I want to keep all of the relevant info for the 1999 and possibly 2000 in one place...

I plan on using Megasquirt 1 (3.0 PCB) with only fuel control first, then spark+fuel, then spark+fuel+turbo.

The '99 uses the BP-4W engine which doesn't have Variable Valve Timing (VVT) but does have a Variable Intake Control System. Apparently VVT was introduced on the 2001 model (BP-Z3 aka BP-VE) In case anybody is interested, Wikipedia has a lot of good info including the followingI'm not an expert solderer so I'm going with the prebuilt Megasquirt 1 with 3.0 PCB from DiyAutoTune (link).

So, it looks like the Hall effect sensor was removed according the Miata Engine History Page Which means I'm going to have to swap out the magneto-CAS for the optical Hall Effect version from earlier engines.

Questions:
How much does an NA CAS cost?
Am I going to fry my 1.8 coils when I go spark?
I've heard of some issues with the VVT and spark, those don't apply to 99-00s right?
Should I start with the default firmware if I'm only doing fuel at first? Or should I go MSnSE from the get go?
How much rewiring is required if I go with the prebuilt DIYAutoTune kit?

Thanks for any help here, I plan on putting together a build log so future squirters have an easier time.

 

You don't swap it out, you leave it as is. You just add another one from an NA.

$25-100 for a used sensor. I got mine for $40.

Not if you use dwell times that make sense (and worked for people here).

You dont have VVT, so no.

Get MSnSE from day one, no reason not to.

In the engine bay, just the CAS (4 wires). Much more inside the cabin where you will have to tap into the stock harness.

 

Just got my prebuilt Megasquirt, Megastim and Wideband O2 sensor. Still lots to learn, like how to plug it in to my car... I'll keep updating this thread...

 

Nice router stand

 

Thanks You know, it'd be nice if software existed that, with an adapter, could take over for the MegaStim. In fact, I'm working on an open source driving simulator and I'm hoping that some day I can tune a virtual engine using a real megasquirt box. Could be a good learning tool. I built a simple 1 piston engine in c# a while back so I think computers are fast enough to do it.

 

Thanks for the info Reverant. Still a couple of stupid questions.

Before I start chopping things up, the ECU is under the passenger dash in the '99 right?

I need a new Crank (not Cam) angle sensor correct?

Are there any wiring guides for the Miata? Or do the colors match up with the Megasquirt diagram.

Would a MegaSquirt Relay make my life any easier with the Miata?

Anybody have photos of an installed unit?

Thanks

 

I don't know where the ECU is on a '99, it should however, be either under the passenger foot rest or behind the passenger's seat.

You need a CAS from a 90-97. Prefer one from a 94-97, they are generally in better condition and more robust. A CAS from these cars is BOTH a crank and a cam sensor, two sensors in a single housing. As for wiring guides for a '99, better ask the emanage boys. A relay board would propably make your life somewhat easier, but not much.

Jim

 

99 the ecu is under drivers side dash.

 

And on my 99 its the passenger footwell. Different locations for different markets it seems...

 

Thanks for the info, I'm going to the mechanic today to find out on an American car. Won a used 94/95 CAS on ebay for $41, should be here in a few days.

 

OK, accoring the large brained mechanic, the ECU on my California '99 is in the dash on the driver's side, he explained how to remove it. I'll get some photos online when I do.

 

I just bought a CAS on ebay but I'm wondering what, in addition to the sensor, I need to buy to make it work (wires, harnesses, screws, etc.)



Thanks

 

I take it no one knows the answer to this one? I might look tomorrow if i get a chance. Seriously need a Factory Manual though, if only just for the pictures.

 

You need the Megasquirt, a few 470k & 1k resistors, and it probably wouldn't hurt to get the short wiring harness. You can reuse all the mazda sensors.