Fault code 3 No G signal

[Slipstreem]

Hey y'all. Been a long while since I was on these forums (gotta love real life issues).

So I encountered a problem with my 93 Miata tonight. About to leave for work and she won't start. Just cranks and cranks but never catches.

I called a cab and while I was waiting I looked for any fault codes. Got three blinks. After some google searches the problem points to the CAS.

Still waiting for my cab I decided to look at the connection that clips into the CAS. There was no bent or broken pins. The wire and loom itself is still intact.

I plan on buying a "new" CAS from Treasure Coast but, since they are closed on the weekends I wanted to get some ideas from you guys. Have any of you had the same problem? Was it indeed the CAS? Is fault code 3 specifically related to the CAS or should I look at other places such as the MAF?

As always thanks in advance for the help.

[— kung fu jesus —]

I had that code, it was the CAS. The CAS is essentially a monitor that 'watches' the intake camshaft, and sends a signal to the ECU. Without that signal, the ECU cannot do a number of things, and your car won't start.

This contains probably more than you ever wanted to know about the CAS:
http://www.rivercityroad.com/garage/cas.htm

And from the FSM:



You can check for the G signal at pin 2G on the ECU harness.

Also make sure your timing belt didn't snap.

[90blue]

Also had this happen.
It was a broken wire at the connector.
Check the yellow w blue wire.
It is the wire at the end of the connector, not the black one. It relates to code 3.

If you need a new connector check here;
http://mazdaroadster.net/PopVII/Cheap%20Mods.php

24. CAS Plug.



Broke one of the 4 wires flush with the top of the CAS plug. Unable to find a replacement at any of the local salvage yards and found an on-line parts yard that would cut one off with a couple inches of wire so I could splice it in. Unfortunately it would cost me 1 and ½ days out of my meager pension check. Carried my CAS and broken cap to a local Radio Shack. Walked out with this Disk Drive Y-Cabl (part # 2780766) for $5.99. Came with 1 male and 2 female connector plugs. Seems a nice snug fit and works fine. At this point it has been installed for about a month and 900 miles.

Now have time to scout around and find a proper plug! As needed, still have the second plug if this one fails. That means then that will need to intensify my search efforts or loosen the purse strings a bit. Maybe it will last until tomorrow or another 18 years. Dunno. Understand now you probably have a spare and unused plug inside your computer that will work. Free is a better option. In any event it made a quick and cheap roadside repair!

Another advantage with this cable is in trimming a little plastic from a remaining plug to fit inside the wiring cap. This leaves the remaining plug to check signals using a multimeter or O’Scope … with or without the engine running.

[Slipstreem]

@KFJ That is indeed a lot of info lol. But I appreciate it. Can always use more knowledge.

@90blue That's an incredible trick. I believe I have one of those cables in my computer parts pile. Although I didn't see a broken wire I will definitely keep in this in mind.

Thank you for the help. I will go as planned and buy a CAS. I'll report back here once I finish the job.

[90blue]

That will cost you big.
See if there is anyone in your area that will lend you one before you buy.

[Slipstreem]

That will cost you big.
See if there is anyone in your area that will lend you one before you buy.

I don't have many friends and out of the few that I have I'm the only one with a Miata. Treasure Coast has them priced at $85. Which is not a bad deal if you ask me. It's just a matter of if they have any in stock.

[— kung fu jesus —]

When mine went down suddenly (when I came out of work to go home), I bought and keep a spare. There seems to be little to warning when these things fail.

[Slipstreem]

As promised here's the update.

After 3 hours of fighting the position between the CAS propeller and the cam I finally got the stubborn **** installed. Hooked all the connections back up then turned the key. Started up without breaking a sweat. After playing with the old CAS I discovered that the propeller shaft seized.

Thanks again so much for the help!

[— kung fu jesus —]

Nice!

Glad it was a relatively easy fix. Usually when I need to do CAS removal, I take out the valve cover and the cap that secures the CAS to the head. Seems like more work, but it's a lot easier.