Test a 90 CAS?

[LKWTSI]

I'm done searching and I have found lots of cool stuff. BUT nothing on the 90 CAS. I am rebuilding my engine and found the wires cracked and bared on my CAS. Figured I give it a shot and tear it down and rebuild it. I did and it wasn't that hard. BUT now the biggie....

HOW do I test the CAS to make sure it's sending the signal. I've seen multiple threads about the later models and what voltages are expected and such and most test the CAS in the car with all systems running. But is there a way to bench test and what voltages and pins are to be used??

I've read through both DSM electrical and service manuals and my Haynes, they don't have any hints.

Hope someone has ideas.

Thanks.

 

[19Eclipse90]

>>The CAS has four wires. Two are 12v and ground. The other two are the signal wires for the TDC and CAM inputs to the ECU. They are pulled up to 5v by the ECU and the CAS pulls them low. TDC will pulse twice per rev and the CAM 4 times. Turning the CAS by hand will allow you to see the signals with a voltmeter. It's still possible for the CAS to be bad when hot or at speed but this will identify the really dead ones.>> -Steve

The four wires are:
Red - Power
Black - Ground
White - TDC Input
Yellow - CAM Input

NOTES: The CAS must be plugged in to the harness; the key must be in the "On" position for testing. Make certain the paperclips -- if you choose to use that method -- do not touch each other.

Hook a wire from the red to the (+) battery terminal and the black to the (-) battery terminal. Use a voltmeter to read the pulses while turning the CAS by hand. I jammed paperclips into the rear of the CAS-to-harness plug for accessible leads for the (+), (-), and voltmeter. The CAS must be plugged into the harness and the key must be in the "On" position to test.

>>The voltages on the CAM and TDC signals should switch cleanly between close to 0v or 5v as you turn the CAS.>> -Steve

 

[LKWTSI]

The CAS has four wires. Two are 12v and ground. The other two are the signal wires for the TDC and CAM inputs to the ECU. They are pulled up to 5v by the ECU and the CAS pulls them low. TDC will pulse twice per rev and the CAM 4 times. Turning the CAS by hand will allow you to see the signals with a voltmeter. It's still possible for the CAS to be bad when hot or at speed but this will identify the really dead ones.

The four wires are:
Red - Power
Black - Ground
White - TDC Input
Yellow - CAM Input

NOTES: The CAS must be plugged in to the harness; the key must be in the "On" position for testing. Make certain the paperclips -- if you choose to use that method -- do not touch each other.

Hook a wire from the red to the (+) battery terminal and the black to the (-) battery terminal. Use a voltmeter to read the pulses while turning the CAS by hand. I jammed paperclips into the rear of the CAS-to-harness plug for accessible leads for the (+), (-), and voltmeter. The CAS must be plugged into the harness and the key must be in the "On" position to test.

The voltages on the CAM and TDC signals should switch cleanly between close to 0v or 5v as you turn the CAS.

Thanks for the reply But I already read the procedure or something very close in my searches.

MY problem is my car is in bits. I guess what I'm trying to figure out is if there was any way to do this test outside of the car. But it seems not. SO, do I have to plug it into my harness and hook up the battery?? will this be sufficient or does the ECU need signals from other stuff to register the fact that ONLY the CAS is plugged in and do the test or do I have to plug in other components that affect the ignition circuit for the ECU.

Please excuse me guys, if I'm making this more complicated than it needs. I tore this thing down to the very bones, ie. disk out and cut wires and redid connectors and resealed all the cap up. I just don't want to stick this back on and find out that it's toast. I'm a couple of months away from getting this back on the road and I don't want to try and figure this out when the time comes, and have to delay while I search for a new CAS.

 

[steve]

That looks an awful lot like a copy and paste of something I wrote.
If that's the case I really prefer it's quoted or attributed to me.

Ah here it is. http://www.dsmtuners.com/forums/newbie-forum/238267-cas-diagnosing-steps.html#post50470620

I guess what I'm trying to figure out is if there was any way to do this test outside of the car. But it seems not. SO, do I have to plug it into my harness and hook up the battery?? will this be sufficient or does the ECU need signals from other stuff to register the fact that ONLY the CAS is plugged in and do the test or do I have to plug in other components that affect the ignition circuit for the ECU.

The ECU just makes it easy to provide the life support needed for testing but all the key information is right there. You need to provide +12, ground, and two +5v pull ups (I'd have to look at the ECU but something between 1k and 10k resistor to +5v should be fine) for the two signal lines.

If you not able to understand what I just wrote then you shouldn't be messing with it.

 

[19Eclipse90]

That looks an awful lot like a copy and paste of something I wrote.
If that's the case I really prefer it's quoted or attributed to me.

Fixed. Sorry about that, sir.

 

[steve]

Thanks!

 

[LKWTSI]

That looks an awful lot like a copy and paste of something I wrote.
If that's the case I really prefer it's quoted or attributed to me.

Ah here it is. http://www.dsmtuners.com/forums/newbie-forum/238267-cas-diagnosing-steps.html#post50470620



The ECU just makes it easy to provide the life support needed for testing but all the key information is right there. You need to provide +12, ground, and two +5v pull ups (I'd have to look at the ECU but something between 1k and 10k resistor to +5v should be fine) for the two signal lines.

If you not able to understand what I just wrote then you shouldn't be messing with it.

Thanks for the input. I do understand quite a lot, but one of the things that I beg to differ is, that someone willing to learn "something new", sometimes has to go dig a little deeper than the basic knowledge level. I have worked on a ton of different cars and machinery before and every now and then something new comes along and either through careful diagnosis or being taught the person NOW knows how to fix or use something. I appreciate you providing some information, but exactly what do you mean by "and two +5v pull ups (I'd have to look at the ECU but something between 1k and 10k resistor to +5v should be fine) for the two signal lines."??
I'll be the first to stop and admit defeat if I get past my level of technical capabilities, but please don't assume just because you can quote nice terms that everyone will understand the language and if not then don't screw with it..

I might like to learn something new and use it in the future, but please don't write me off, over a term that I may or may not have heard off.

As always, I am amazed at the level of expertise on this website and I respect the honesty and integrity of the members who provide replies to questions. It's why I keep coming back to ask.

 

[steve]

I appreciate you providing some information, but exactly what do you mean by "and two +5v pull ups (I'd have to look at the ECU but something between 1k and 10k resistor to +5v should be fine) for the two signal lines."??
I'll be the first to stop and admit defeat if I get past my level of technical capabilities, but please don't assume just because you can quote nice terms that everyone will understand the language and if not then don't screw with it..

I'm not quoting nice terms but using the correct terminology to describe a specific thing. I even explained indirectly what a pull up was in what I wrote. It's a resistor connected between the signal wire and the pull up voltage. If you want to know more read this. Pull-up resistor - Wikipedia, the free encyclopedia

It's not a matter of me not thinking you can't figure it out, but more one of can you destroy something if you try and don't understand what your doing.

If you make a mistake in what you hook up to which wire the CAS will be ruined. So if you don't know off hand what I'm telling you, you might not want to go down that path and if you do understand that you might not get the help you need before it's too late.

 

[LKWTSI]

I'm not quoting nice terms but using the correct terminology to describe a specific thing. I even explained indirectly what a pull up was in what I wrote. It's a resistor connected between the signal wire and the pull up voltage. If you want to know more read this. Pull-up resistor - Wikipedia, the free encyclopedia

It's not a matter of me not thinking you can't figure it out, but more one of can you destroy something if you try and don't understand what your doing.

If you make a mistake in what you took up to which wire the CAS will be ruined. So if you don't know off hand what I'm telling you, you might not want to go down that path and if you do understand that you might not get the help you need before it's too late.

Hey I appreciate the concern and believe me I wouldn't want it any other way. But sometimes that's the risk we have to take, in order to learn the hard way. As it is though I already have had the thing apart and I believe it was you who responded in another thread, about the O-ring being hardened and cracked (therefore, probably junked) so I figured while I search for a replacement CAS, why not learn something about this one and in doing so find out what exactly makes the CAS work.
This CAS may already be toast from me taking it apart, BUT, would like to test my skills and see, hence the OP. I was only trying to put all the pieces in order so I can determine for myself, whether this would be something I could do again, if needed or at the very least learn that taking a CAS apart is not for the inexperienced.

I appreciate any and ALL advice, from moderators like yourself ( and obviously, very experienced ) to the less equipped such as me .

As for the "pull up" thanks for the link. I'll be doing some reading and self educating.