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Unread 04-28-2015, 03:05 PM   #1
Jabo
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1994 YJ Wrangler 
 
Join Date: Jan 2010
Location: MA
Posts: 220
Another no spark issue

Hello all.

I have a 94 2.5 manual. January I drove it and it was fine. I just finished a restore and tried starting it and cranks and cranks and cranks but thats it. I have been reading lots here and found some goon info.

So right now I am not getting spark. I get power to the coil. I replaced the coil, nothing. I just replaced the crank position sensor, nothing.

So 12v to the coil with key on. I checked the volts while trying to start it and it dropped to 5v. Again this reading was from the harness going to the coil.

I am getting fuel, pump is working, pressure in the rail.

Also I tried checking volts to the injectors while cranking and got nothing.

I am at a loss here. Why would I drop volts to the coil while cranking?
Any help would

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Unread 04-29-2015, 06:28 AM   #2
Que89YJ
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1989 YJ Wrangler 
 
Join Date: Apr 2008
Location: Detroit, Michigan
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It is how you are reading the voltage at the coil. If you read across the 2 pins the signal gets pulsed and voltage on a digital meter is slow to read so it appears to drop. Read it to battery ground. The same with the injectors.
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Unread 04-29-2015, 06:36 AM   #3
Jabo
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Thanks for the tip. I'll try that this morning.
Any thoughts about my no spark issue?
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Unread 04-29-2015, 06:38 AM   #4
Que89YJ
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1989 YJ Wrangler 
 
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Start by checking and posting codes:

http://www.jeepforum.com/forum/f12/h...codes-1257145/
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Unread 04-29-2015, 06:53 AM   #5
Jabo
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Check engine light does not comes on at all... ???
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Unread 04-29-2015, 07:01 AM   #6
Que89YJ
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1989 YJ Wrangler 
 
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Do the voltage checks on this post. You might have a bad ecu and either need to repair it or replace it:
http://www.jeepforum.com/forum/f12/9...lained-490788/

If you have the bad ecu then this:
http://www.jeepforum.com/forum/f12/c...rs-ecu-492597/
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Unread 04-29-2015, 10:18 AM   #7
Jabo
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All the steps in that link about checking ecu check out good.

Although now I have a new problem. Now I am not getting 12v to the coil where I was yesterday. I love gremlins...
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Unread 04-29-2015, 10:51 AM   #8
Que89YJ
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If you have power on pins 3 and 9 and no check engine light then you need to check the bulb and if its good then do the ecu repair. You will not have power because the asd relay pulls in and sends power to the coil, injectors, and the alternator. There are several giveaways on the issue. The CEL not lighting when you tiurn the key. The fuel pump and asd don't operate when you turn the key. You can leave the key on for 10 minutes or more and the cel might come on and the relays operate. Then it will start.
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Unread 04-29-2015, 11:16 AM   #9
Jabo
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I had power only to pin 3
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Unread 04-29-2015, 12:20 PM   #10
Que89YJ
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1989 YJ Wrangler 
 
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Did you check 9 with the key on? If you did then you have a blown fuse in the fuse panel at the drivers feet. The fuse is either the ign. lps or the dome fuse depending on the year.
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Unread 04-29-2015, 01:16 PM   #11
Jabo
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I have power at pin 3 and with the key on I get power to pin nine.
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Unread 04-29-2015, 01:29 PM   #12
Que89YJ
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1989 YJ Wrangler 
 
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Then you need to check the bulb for the check engine light. If it is good you have a problem with the ecu. Does the Jeep have those issues? If it does then you need to do the ecu repair.
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Unread 04-29-2015, 02:12 PM   #13
Jabo
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I really do appreciate the help. The bulb is blown. I have to run into town to get some bulbs.
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Unread 04-29-2015, 02:54 PM   #14
Lemoore-on
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1992 YJ Wrangler 
 
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I'm watching this thread my 92 is doing the same thing only my check engine comes on.
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Mike

92YJ with some stuff done to it.
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Unread 04-29-2015, 05:56 PM   #15
Jabo
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Recap:

Yesterday, shift light would come on when I turned the key to on, you could hear the fuel pump priming. I had power to the coil but not out. I changed the Crankshaft position sensor no change same results.

This morning I followed the link to check the ecm and all checked out good.

I turned the key on and no shift light, no check engine light, no fuel pump noise, no power to the coil. I replaced check engine and shift bulbs (still not working).
I went through every fuse under dash and under hood and they all work.
I checked all relays and all seem to be working. I put each one it the horn relay ant honked and they all worked.

Very frustrating...
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