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How to test 1g CAS?

Posted by SubversionX, Feb 23, 2011

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  1. SubversionX

    SubversionX Proven Member

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    I've seen a couple examples of the harness, but they all show that there are three wires leading to the CPS. Mine has four. Does anyone else's have four? How do I test each one? What order do the wires connect to the CPS? Lots of confusion, meaning I need LOTS OF HELP!!!:confused:

    Thanks!
     

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    1997 Mitsubishi Eclipse GST
    · 2G DSM
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  2. razrman8

    razrman8 Proven Member

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    Precisely what sensor are you referring to? Many times terms like so are misconcepted.
     

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  3. SubversionX

    SubversionX Proven Member

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    Cam angle sensor; sorry, i get just as confused. I'm not getting any spark to my spark plugs, and was told this might be a reason why. Is that true?
     

    332  0

    1997 Mitsubishi Eclipse GST
    · 2G DSM
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  4. keviebaby

    keviebaby Proven Member

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    Could be the coil pack or the power transistor. How are you checking for spark? Are you just holding it up in the air or grounding it to something? Your CAS could be off 180°.
     

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  5. SubversionX

    SubversionX Proven Member

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    I'm using a spark tester. I've used the multimeter on the transistor and I'm getting good continuity.

    How do I make sure that my CAS is at the right angle? I think I may have fried my CAS, also; there was smoke coming out of it the other week...

    I've read that the CAS is supposed to have 3 wires coming from it? Mine has four... and I don't know what any of them do?

    There are also some stray wires, and I'm having trouble identifying them...
     

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    1997 Mitsubishi Eclipse GST
    · 2G DSM
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  6. gofer

    gofer Moderator

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    Moving thread to the Electrical Tech forum, where it should have been posted in the first place.

    You'v got your acronyms backwards, the CPS (CRANK position sensor) and the CAS (CAM angle sensor). The reason why your CAS has (4) wires going to it is because its a 1g CAS, not a 2g like you were probably searching for.

    Your CAS has four wires going to it, a 12v signal and ground the other two are signal wires for the TDC and CAM inputs to the ECU. To test them you'll have to pull the CAS off the head and turn it by hand, this will allow you to test the signals with a multimeter as you spin it. Both the CAM and TDC signal wires should read up to 5v as you spin the CAS, the CAM signal wire pulses 4 times per revolution and the TDC pulses 2 times.

    Heres a pin out of the CAS connector going to the ECU so you can check continuity of the wires and know which wires to test for the CAM & TDC pulses.

    ECU Pins to CAS connector Pins -
    • CAM Signal wire (YEL): Pin 2 at the CAS (4 pulses per revolution)
    • TDC signal wire (WHT): Pin 1 at the CAS (2 pulses per revolution)

    When you pull the CAS off to test it you need to make sure you don't have it spun 180* out or else your motor won't start at all, heres what it SHOULD look like. The motor needs to be at TDC when installing it like this...

    cas-linedup.jpg

    :dsm:
     

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  7. SubversionX

    SubversionX Proven Member

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    Sorry gofer :D it won't happen again. So, do I just find TDC and keep the CAS sensor aligned as I install it back in? I've got a guy who will probably let me use his 1g CAS to test and see if mine is fried. What else should I be checking in my ignition sys, to find why I'm not getting spark?
     

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    1997 Mitsubishi Eclipse GST
    · 2G DSM
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  8. gofer

    gofer Moderator

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    Sure it won't. ;)

    You'll want to check that spark is getting to the engine as its turning over. Everyone has their own way to do this however, I've found the easiest is to use two people to make it effective. One person should be sitting in the front driverseat to crank the car over, the other should be under the hood watching for the spark. To do it, remove a spark plug (start at 1 or 4 and work your way down the engine) and plug it back into the plug wire after its out of the motor. While holding the spark plug wire, ground the threads of the spark plug on the valve cover, then cue the person to crank the car over. Verify that there is spark between the electrodes, then repeat for the other (3) cylinders and write down your results.

    Coil Pack testing

    Ignition Power Transistor (PT) testing

    You may also check the wiring for the 1g CAS was done correctly, who knows how bad it is if you didn't do it yourself.

    CASwiring.gif

    :dsm:
     

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  9. SubversionX

    SubversionX Proven Member

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    It's weird; I've got a 1g cam sensor plug. I take it that the 'white' wire is the same as the 'brown' wire?
     

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    1997 Mitsubishi Eclipse GST
    · 2G DSM
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  10. gofer

    gofer Moderator

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    The connector is keyed to only fit on the CAS one way, the diagram above shows the pin out in relation to that key. You can take a picture of connector in relation to its wires if you'd like?

    :dsm:
     

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  11. SubversionX

    SubversionX Proven Member

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    Yup, here it is. 4-wire harness

    DSC00381.jpg
     

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  12. gofer

    gofer Moderator

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    Thats good you took the time to take a picture but that definitely isn't the CAS connector, and even if it was, it doesn't show the connector in relation to its wires coming out of the back of it. :ohdamn:

    I do see the CAS though and it is a 1g!

    :dsm:
     

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  13. SubversionX

    SubversionX Proven Member

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    The female end in that picture is what's pigtailed off of the CAS, which has four wires leading from it. I tried posting earlier with some pictures, but I assume it didn't work. I'll try to reload them when I get off 24 hour duty at work(on my 21st birthday)...
     

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    1997 Mitsubishi Eclipse GST
    · 2G DSM
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  14. gofer

    gofer Moderator

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    Is this the CAS that you've got? Happy Birthday by the way.
    DSC_2485.jpg

    :dsm:
     

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  15. SubversionX

    SubversionX Proven Member

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    Yes sir! That's definitely it!
     

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    · 2G DSM
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  16. gofer

    gofer Moderator

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    Thats a '89-'90 CAS, where is the brown wire you're talking about though?

    :dsm:
     

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  17. SubversionX

    SubversionX Proven Member

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    I was just told by someone it was probably the 89 or 90 CAS, as you said. I'm just having trouble identifying the colors of the wires, is all. The yellow and white are hard to distinguish, probably due to age and wear
     

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    1997 Mitsubishi Eclipse GST
    · 2G DSM
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  18. gofer

    gofer Moderator

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    Looking at the picture above the wires go in this order from L to R.BLK, RED, YEL, WHT

    Test it with a multimeter using the write-up I posted above, if it doesn't pass I'll give you a list of cars that the '90 CAS came on. That way you can make a trip to the junkyard and get a new one, believe it or not they didn't just come on DSM's.

    :dsm:
     

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  19. SubversionX

    SubversionX Proven Member

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    Really weird: I was able to get a reading for a little bit and then all of a sudden there wasn't any continuity. So, I suppose I'll try and hit up the pick n pull for a used one. What other types of cars use that type of CAS?
     

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  20. gofer

    gofer Moderator

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  21. SubversionX

    SubversionX Proven Member

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    So, I'm trying to find one off the site's marketplace and ebay, for the best price, but am having trouble identifying exactly what I need. Is there a way I can look up by part number? What exactly do people mean by "black top" and "green top?"
     

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  22. gofer

    gofer Moderator

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    Yours is P/N MD121786 and came on the 89-90 DSM's
    cas-greenlid-early_small.jpg

    Green top is P/N MD148855 and came on 91-92 DSM's, it plugs in on top though but works the same as yours now... its a optical CAS.
    cas-greenlid-late_small.jpg

    Black top is P/N MD184529 and came on the 93-94 DSM's and also plugs in like the 91-92 green top. The black top is a "Hall Effect" sensor though, which uses magnets similar to the '2g CAS.
    cas-blacklid_small.jpg

    All of them will work for you, the black top is the best of the three but more expensive.

    :dsm:
     

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  23. LKWTSI

    LKWTSI Proven Member

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    Hope you guys don't mind me jumping in on this. I was about to start a thread on this very thing and figured this was appropriate and not considered hijacking:D

    I'm just finishing up a complete rebuild and inregard to the CAS, I did what was said about setting the tab/notch in alignment and making sure the #1 was a TDC, but as far as any manuals I've read and anything I can find using search, what else is there to do once this is installed like in post #6.

    Am I to assume as long as I set the CAS properly and the #1 is TDC, then I just tighten the bolts up and call it good:confused: At what point in the process would I have to adjust the CAS? I read that if the timing is grounded and you set you timing light for 5*BTDC, you don't have to adjust the CAS if your timing is correctly showing, ONLY if the marks don't line up at 5* mark..am I correct or missing something.

    Thanks for the help.
     
  24. SubversionX

    SubversionX Proven Member

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    I assumed that you would just tighten the bolts up, but now I'm second guessing myself. you could be right, but I have no idea. Wish I could be of more help :confused:

    I installed a new CAS yesterday, and still have no spark. I've used the multimeter on the CAS, the power transistor, and coil pack. Does anyone have a diagram of the ignition system from the coil pack all the way back?
     

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    1997 Mitsubishi Eclipse GST
    · 2G DSM
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  25. iugrad92turbo

    iugrad92turbo Supporting Member

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    No spark did you check the ecu?
     

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