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Can you damage a CPS by not removing it prior to a motor swap?

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Old 09-01-2013, 09:32 AM
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Default Can you damage a CPS by not removing it prior to a motor swap?

I just did a motor swap in a 94 Cherokee. Now, I'm getting no spark at all. I've checked my grounds and can't find anything there. The CPS worked before the motor swap. Same with the ignition coil (I re-used both). Now after the swap....I've got no spark coming to the coil.

Any thoughts?

I didn't remove it before I installed the motor. Could I have smashed it? I was having trouble lining it up anyway...
Old 09-01-2013, 09:35 AM
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"Could I have smashed it?"

Real hard to see over the interwebs. Have you considered removing it to have a "look-see"?
Old 09-01-2013, 09:42 AM
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That's the plan. I'm going to pull it when I get home. That thing is a pain to get to though. I was curious to know if it was possible or probable if anyone had any experience with it.

I guess I could look up how to test it first. That might be easier and allow me to narrow the problem down. Although, there aren't many choices of what could create a no-spark condition.
Old 09-01-2013, 10:02 AM
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You can ohm test it.
Old 09-01-2013, 11:26 AM
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Ohm test read 30 mil between A & B. Between b&C it was reading as Open

I should probably mention that the long block was from a 93 cherokee.

Last edited by rdr8887; 09-01-2013 at 12:35 PM.
Old 09-01-2013, 02:50 PM
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When I rebuilt The 4.0 in my 88 I didn't pull the cps and when I reinstalled it and fired it, I couldn't get it to run right so after a week of going over everything i pulled the cps and it was damaged .
Old 09-01-2013, 04:25 PM
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Yup. Turns out the answer to my initial question is yes. I cracked it. $65 later...she's alive. Turns out I had the timing 180 off. But it's fixed now.

Transmission is a little shaky, but low on fluid. Anothe quart and she should be running strong again. Now if I can only figure out how to remove 3 years worry of pinestraw muck from the paint....
Old 09-03-2013, 09:47 AM
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For all you guys saying ohm test it, a way more reliable way to test the CPS is to back probe A and B, pull the ignition coul wire out, and with your meter set to ACV crank it. You should see at least .5v after a second of cranking.
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