2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

no voltage at cas plug but why??

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Old Sep 20, 2003 | 09:48 PM
  #1  
novicaine's Avatar
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no voltage at cas plug but why??

So I cant get any spark out of my 89 NA with an 88T2 motor i swapped into it. Yes I DID swap all the wiring and ecu(before you ask!!)with the motor. Well everything works except the fuel pump isnt turning on and it wont create spark. There is power at the coils, and when I turn the key to on I can hear the relay by the intake click on and there is power on 2 terminals of the main relay. So the weird thing is that I cant find any voltage at the plug to the CAS. Which prongs should show power? And what would cause this to happen, and last Q is this most likely the reason I am not getting any spark as I suspect it is?
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Old Sep 20, 2003 | 09:59 PM
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There isn't supposed to be voltage coming out of the CAS, its supposed to be a resistance check between the pins in the plug. Usea Haynes manual or a Factory Service Manual (FSM) for instructions on how to check the CAS.
For the fuel pump, check the AFM. If the flapper door doesn't open, then the pump circuit won't turn on. Using the FSM which is available online for free at www.fc3s.org check the AFM as instructed. It will show you which pins are for power to the fuel pump. Also, there is a plug on the wire harness that you can jumper with a short wire. This is supposed to bypass all circuits and test the fuel pump. Did the TII motor work before you put it in the 89 N/A? how long ago did you swap it? How are you checking for spark?
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Old Sep 20, 2003 | 10:07 PM
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Im in the same boat you are, T2 swap, and no spark

I was told to check if the AFM was pluged in and make sure ground on the engine is solid
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Old Sep 20, 2003 | 10:33 PM
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the fuel pump won't turn on untill you jumper the plug by the pass shock tower and turn the key on
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Old Sep 20, 2003 | 11:01 PM
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Not at all? So i just have to jump it once and then it will work from now on?


not trying to hijack
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Old Sep 21, 2003 | 05:44 AM
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The CAS runs a pair of magnetic pick-ups (two wires per pick-up, 4 wires total) that generate very LOW voltages (under 1VDC typically) when you spin the wheel.&nbsp This wire is shielded back to the ECU for a reason.&nbsp There is no power going into the CAS.&nbsp If the CAS isn't spinning, it'll not generate any power through the pins.


-Ted
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Old Sep 21, 2003 | 10:10 PM
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ted so how can I guage wether its working or not? can I out a dmm on 2 of the pins off the cas side of the 2 clips, crank the engine and look for a value?
Also why would I need to jumper the plug for the fuel pump? Ill try it tomarow regardless.
Thanks for the input men
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Old Sep 22, 2003 | 07:31 AM
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From: n
The pairs should ohm out pretty close - I think the service manual tells you the actual resistance value.

If you spin in quickly and check for voltage, there should be a slight voltage reading off the leads for each pair.

These CAS units rarely fail.&nbsp If anything, check to make sure the CAS plug is snugly connected!&nbsp As an extra, you might want to clean the plug pins with contact cleaner.



-Ted
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