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Unread 02-24-2014, 02:54 PM   #1
XJ93
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1993 ZJ 
 
Join Date: Apr 2009
Location: Michigan
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Ignition issues-Firing early/late?

I am stumped on this one. I have had some ignition issues I have been chasing for a while now. I changed out my cap and rotor and here we are.. It seems as if the timing is way off, I have scorch marks everywhere inside the cap as if it's being fired between the posts as well.. Anyone run across this before or know what I should look for now? No codes being thrown other than 12 33 55. Takes a few revolutions before she fires up.
95 with 4.0 and auto.

0224141535.jpg   0224141535a.jpg   0224141536.jpg  
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Unread 02-25-2014, 07:33 AM   #2
XJ93
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Nobody has seen this before? I even asked my uncle who had been a mechanic for a great many years, and he was stumped at what he saw. Is it possible that the distributor is out of time? The Jeep has always started and run, well enough, since I have owned it.
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Unread 02-25-2014, 01:26 PM   #3
Que89YJ
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1989 YJ Wrangler 
 
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XJ what ignition issues do you have? What driving symptoms do you have and what have you tested and done so far?
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Unread 02-25-2014, 02:42 PM   #4
XJ93
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I did a tune up about 8 months ago, after a while the Jeep started taking more than a couple cranks to fire. Used to fire right up as soon as I hit the key. Then performance started going downhill. Poor fuel mileage, lack of power when hitting the go pedal. I had chalked it up to the cracked exhaust manifold and an O2 sensor..but then I decided it was time for another tune up and discovered this. Along with bright red spark plug electrodes.
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Unread 02-25-2014, 02:59 PM   #5
XJ93
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When I did the tune up this time around I found that my ignition coil was cracked and swollen so I replaced that as well. When I did the last tune up I had used double platinum plugs, this time around I went back to copper plugs, so far it seems to like this set up better, but I am not sure if this is just a band aid to an underlying issue that I am missing.
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Unread 02-25-2014, 05:44 PM   #6
Que89YJ
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1989 YJ Wrangler 
 
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Location: Detroit, Michigan
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The arcing can't happen unless there is continuity. I think the cap isn't telling you that you have a problem but if you want to stop arc over use some finger nail polish. Coat the rotor up to the very end so just the flat part is exposed. You usually only get arc over from water in the cap.
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Unread 02-26-2014, 11:00 AM   #7
XJ93
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Okay, thanks Que
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Unread 02-26-2014, 11:19 AM   #8
Que89YJ
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1989 YJ Wrangler 
 
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Location: Detroit, Michigan
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Is that metal shavings on the rotor contact for the cap? You definitely need to clean the contact surfaces.
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Unread 02-26-2014, 02:51 PM   #9
XJ93
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It's scorched, I just put new cap and rotor on. I had a couple people tell me that because I was running platinum plugs and now knowing that I had a weak coil, the plugs wanted more juice than the coil could put out. This apparently had the coil trying to "catch up". Not really sure if that's true or not but time shall tell. I am going to keep an eye on the new cap and see what happens in the next few weeks. Right now I have to replace the ECM so just one more thing to deal with.
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Unread 02-26-2014, 08:24 PM   #10
Que89YJ
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1989 YJ Wrangler 
 
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Why do you need to replace the ecm?
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Unread 02-27-2014, 10:50 AM   #11
XJ93
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When I originally purchased the Jeep the P.O. had replaced the ecm with one from a Cherokee, because they're all the same he said. I had issues with the alternator overcharging and after having it all checked out the ecm wasn't regulating like it should have been. I then went on an internet search and finally found the ecm I needed, and this darn rig takes a very hard to find ecm. After fighting with that company for two months and finally getting my lost ecm I decided I would never deal with them again. Now I am having alternator issues again and it traces back to a faulty ecm. This time I went to the dealer and got one...barely.
Before I replaced the Cherokee ECM the YJ would fire on the first crank every time. After replacement it would take a couple revolutions to fire, I just chalked it up to the ecm needing to learn the sensors.. I took it to a reputable shop that I go to when I am completely stumped on something, and they questioned whether the ecm I had purchased had been faulty from the start.
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Unread 02-27-2014, 11:19 AM   #12
Que89YJ
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1989 YJ Wrangler 
 
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I actually agree. The alternator field control almost never goes bad. If you are up for troubleshooting I might be able to help.
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Unread 02-27-2014, 12:54 PM   #13
XJ93
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Sure, I would love your help Que. I have the electrical FSM downloaded on my computer here at work. What should I start with?
I should mention that I recently replaced my alternator with a 136 amp alternator. Don't know if that would make a difference or not but since I have an Optima battery and a winch I wanted to make sure I had enough juice.
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Unread 02-27-2014, 08:36 PM   #14
Que89YJ
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1989 YJ Wrangler 
 
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Location: Detroit, Michigan
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It doesn't change a thing as far as control. First thing does it start and run?
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Unread 02-28-2014, 07:41 AM   #15
XJ93
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It does fire and run, albeit it takes a couple of cranks to get going. Fuel mileage is horrible as well.
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