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Unread 11-23-2011, 02:03 PM   #1
jeepcrazy93
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1993 YJ Wrangler 
 
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No power going into coil

I am trying to finish up my 4.0 swap for my 93. I had the jeep running but a few days ago I tried starting it and the motor turns over but no spark. I have no spark after the coil or power going into coil. I have replaced the cps (crank), cps (cam), coil. I even linked 87 and 30 together on the ASD relay. I am getting fuel but no spark. I tried to pull the codes and I am getting a few codes. I think the one code is 53. I tried the search feature but nothing that fits my description.

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Unread 11-23-2011, 08:49 PM   #2
laybackman
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The power for the coil comes from your ASD relay which I think is in the PDC. The PCM feed is the ground circuit which shuts off/turns on the ground to the coil.
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Unread 11-24-2011, 04:14 PM   #3
jeepcrazy93
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I'm thinking about checking the new crank sensor to see if its bad.
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Unread 11-24-2011, 05:56 PM   #4
Mark05059
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gotta have power at the coil before the sensor fires it... check the asd relay
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Unread 11-24-2011, 06:56 PM   #5
laybackman
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If the PCM gets a movement signal from the crank sensor you get fuel and spark unless something else prevents one from happening.

I would check for the ground pulse at the PCM that goes to the coil. If the ground pulse is there then the problem is the wiring from that point to the coil.

If the ground pulse is getting to the coil then the problem is no power getting to the coil from the ASD relay. Or the coil is junk.
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Getting older, I have developed some special skills. I have the ability to cough, sneeze, fart and pee at the same time.

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Unread 11-24-2011, 07:20 PM   #6
Noltz
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Yep as mentioned you get constant power from the ASD relay, mounted in the PDC. The ECM is responsible to keep the relay grounded ("ON") when appropriate.

It sounds like you have a break in the wiring, since the fuel pump also is powered from the ASD. You can confirm this is your only issue if you can supply fused power to the coil and then try to start the Jeep. The ECU supplies the ground to the coil, and breaks that ground signal to create the spark when needed.
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Unread 11-25-2011, 08:16 AM   #7
jeepcrazy93
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Thanks guys. Ill check it out next time I get a chance.
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Unread 11-29-2011, 03:27 PM   #8
jeepcrazy93
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I put a new ASD relay in and still nothing. I so I did what Noltz and added fused power wire to the coil and then I got spark. I need to readjust my timing but at least I have spark. Thank you guys.
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Unread 11-29-2011, 07:10 PM   #9
laybackman
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So you bypassed the coil wiring from the ASD relay but you should try to find the problem, OR you end up with a rig that is nothing but gerry rigs!. Trace the coil wire at the coil back to the ASD relay or test that wire for continuity. I believe it goes to a splice. It could be bad at the splice.
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Getting older, I have developed some special skills. I have the ability to cough, sneeze, fart and pee at the same time.

"If we cannot afford to take care of Veterans, then we should stop making them."
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Unread 11-29-2011, 08:57 PM   #10
jeepcrazy93
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You are exactly right. I will be fixing it but i used that bypass to help me diagnose the problem.
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