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Unread 01-27-2014, 09:02 PM   #1
Raptor0206
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1985 CJ7 
 
Join Date: Nov 2008
Location: Las Vegas, NV
Posts: 1,702
1985 CJ7 starting issue

Hey guys I have owned 4 TJ's, one YJ, and now a CJ7. I got this as a project. Wiring harness laying on the engine and dash half undid. I got it all back together the best I can from what I seen. There are a few wires under the dash not pluged in and also in the engine bay. Kinda sucks not being the one that pulled it apart. Anyways iI can get it to pop off for a second and it dies, no difference using starting fluid or not it will only run for a second and die. Restarting it right after it dies and will do the same thing. Giving it gas ddoesn't change anything. I'm thinking something electrical.
Any input would be great. I am at a loss.
thanks

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Unread 01-27-2014, 10:25 PM   #2
Raptor0206
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1985 CJ7 
 
Join Date: Nov 2008
Location: Las Vegas, NV
Posts: 1,702
well i ran a jumper from the battery to the coil and she runs great. So what does that mean?
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Unread 01-27-2014, 10:30 PM   #3
BagusJeep
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1981 CJ7 
 
Join Date: Jul 2009
Location: Bali, Indonesia
Posts: 4,449
Time to break out some test gear.

The best tool in my box is a 12V test lamp. It was an inspection lamp for the cigar lighter but I cut off the plug and bared the wires and pulled them apart. I now have about 5m of wire on each side of the 12V lamp (not LED, a real 12V bulb).

If you hook one end to the battery negative you can go hunting for voltage with the other end.

Start with the coil positive. It is fed with a red with tracer wire. Take it off and see if you have a Dim bulb in Run and a bright one in Start. I suspect you will have nothing in Run and it is because the red with tracer wire has a break somewhere between the coil and the ignition switch, possibly at the resistor wire. This is why when you jump from the battery to the coil you are bypassing that break and it runs great.

Now look at the light blue wire on the S tab on the solenoid. It will be live in Start only. Look at the red with tracer wire on the I tab. It is being energised in Start and that is then being carried up to the coil. As soon as you let go of the key that voltage is not being fed to the I tab and the engine dies.

Now using that tool you can look for voltage all the way back to the switch which you can assess at the column connector. The fuse box / ignition switch diagram has it on the extreme left, the red with tracer wire to "Ignition and Alternator".
84-86fuseboxsch-copy-2-.jpg

schematic-ignition-layout.png

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1981 CJ7 258ci - Bagusjeep
1984 CJ7 258ci - Puthijeep
1981 J20 258ci - Gladys
1995 Cherokee 4.0 - CHEROKEE
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Unread 01-27-2014, 10:44 PM   #4
notlost
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1982 CJ5 
 
Join Date: Oct 2012
Location: Port Hadlock, Washington
Posts: 31
I had this problem. Is the coil wire (+) the only wire on the (I) post on the solenoid? Some solenoids are only hot at the (I) post when the key is at the start position and not hot in the run position. Find the hot wire from the ignition switch and attach it to the (I) terminal also. This way it will get current directly off the battery for engine start AND a hot wire to run.
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