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Shorted ECU?

Old Apr 6, 2012 | 10:39 PM
  #1  
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Year: 94
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Engine: 4.0 Stroked - 4.7
Default Shorted ECU?

Well I took the fam out last weekend to do some trail riding and during the ride the O2 wire somehow fell into the tri-pipe of my header. Didn't notice it til I was driving back and the CEL light came on and engine died. When I discovered the problem, the wires completely melted and looks as though grounded itself to the headers. I've since replaced the wires but no-joy on getting the motor cranked. Checked all fuses, good.

I tried to do the manual CEL blink test but all I get is a solid light. I dont have a code reader either. But from what it seems like is that I may have shorted the ecu... any suggestions other than going out and buying a reader at this point? Its a 94 XJ.
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Old Apr 10, 2012 | 08:47 PM
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Anything?
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Old Apr 10, 2012 | 08:54 PM
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Year: 1995
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Something similar happened to my friends 93 or 94 YJ, Same computer and everything. He had to trace thru the schematics to find that a fuse was mis-labeled fuse. But you checked the all the fuses so the ECU could of fried. Try to find a friend with a similar jeep and swap ECU to see if yours is toast
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Old Apr 11, 2012 | 08:36 PM
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I re-checked the fuses... nothing. Waiting on another ecu to get here to see if that is the culprit.
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Old Apr 13, 2012 | 06:22 PM
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Got another ecu - still not cranking. I cannot get it to tell me the code either. I'm kinda at a lost.
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Old Apr 13, 2012 | 06:29 PM
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Year: 1989 xj sport 2dr
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Engine: 12 hole bosch Injectors
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there two o2s on your yeear?
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Old Apr 13, 2012 | 06:34 PM
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hello
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Old Apr 13, 2012 | 06:39 PM
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oh well read this yet.....https://www.cherokeeforum.com/f2/96-...er-hood-19793/

Last edited by freegdr; Apr 13, 2012 at 06:51 PM.
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Old Apr 13, 2012 | 08:51 PM
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Well I did spot the issue - it was that retchid 30A fuse... apparently with the ignition off it will still read 12V on both sides of the poles (not uncommon). Its always good to check with the meter but nothing beats a good pair of needle nose and your own eyes. Thanks for the info though. I will save the wiring link in my favs.

From reading the post you linked, helped me understand the O2 sensor and the fuse. I grounded out the wires on my O2 sensor to the exhaust which caused the 30A fuse to blow. Bought a new ecu for nothin.
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Old Apr 13, 2012 | 08:52 PM
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Year: 1989 xj sport 2dr
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Originally Posted by FOXxX
Well I did spot the issue - it was that retchid 30A fuse... apparently with the ignition off it will still read 12V on both sides of the poles (not uncommon). Its always good to check with the meter but nothing beats a good pair of needle nose and your own eyes. Thanks for the info though. I will save the wiring link in my favs.

From reading the post you linked, helped me understand the O2 sensor and the fuse. I grounded out the wires on my O2 sensor to the exhaust which caused the 30A fuse to blow. Bought a new ecu for nothin.
your welcome,so it runs now
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Old Apr 13, 2012 | 08:56 PM
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yes it does - and thank you.
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Old Apr 13, 2012 | 08:58 PM
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Originally Posted by FOXxX
yes it does - and thank you.
any time i help a member about a year ago same issue it very common occurance
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