I've benefited from this forum, now I hope to make a contribution.
This addresses a Crank, No Start scenario.
I was having a problem with an intermittent no-start problem on the 96 XJ. It seemed that a cold start first thing in the morning needed extra coaxing to get going. Cycling the key from the -1 accessory position to the run (not start) several times would usually get things going.
Symptoms:
Thoughts:
In computer terms, it seems that there is a problem with the PCM "booting". The real indicators are the two lights. When the lights com on and stay on in the run key position, it takes a half turn on the starter and and it will start. Without the lights coming on the thing can be cranked all day and it will not start.
Eventually it got to the point that I could only get a flash out of the lights and as you can guess it would not run at all.
So the PCM (or whatever 3 letters you are most comfortable with) is sick.
I know most people are going to either order a new one (I'm not sure there is such a thing) or go to the junkyard and grab a $30 replacement.... unless you have a 4-cylinder.....so.
Research time:
I couldn't find much on repairs for the 96-01 units. the most promising thing I found was this:
https://wranglertjforum.com/threads/how-to-fix-a-no-start-issue-caused-by-a-bad-pcm.13876/
I didn't mention earlier but I installed this particular PCM when I bought the Jeep about 5 years ago. I had the old one so I cracked it open to see what it looked like. Bingo! the exact same problem.
The fix:
I replaced the 3 electrolytic capacitors (220 mF, 25V) taking note of the polarity. I Put thing back together and was rewarded with success. It is alive again.
I do have some photos but I'm not able to post them presently. I suggest you visit the link above for the photos and explanation.
One additional note, the electrolyte that leaks out of the capacitors is corrosive, the black stuff you see in the photos is corrosion of the copper traces on the board. When the juice oozes under the protective gel barrier, it begins to act on the copper below. To extend the life of the unit, the gel (which has become loose), should be removed and the area cleaned up with alcohol and a protective layer applied over the bare layers.
Hope that helps someone, YMMV.
This addresses a Crank, No Start scenario.
I was having a problem with an intermittent no-start problem on the 96 XJ. It seemed that a cold start first thing in the morning needed extra coaxing to get going. Cycling the key from the -1 accessory position to the run (not start) several times would usually get things going.
Symptoms:
- You turn the key to the run position and NEITHER the Generator light or the Check engine light come on.
- With the key in the on position, the fuel pump continues to run. In normal operation when the key is turned to the Run position the fuel pump will run for a few seconds to prime the engine and the pump shuts off until you start cranking.
Thoughts:
In computer terms, it seems that there is a problem with the PCM "booting". The real indicators are the two lights. When the lights com on and stay on in the run key position, it takes a half turn on the starter and and it will start. Without the lights coming on the thing can be cranked all day and it will not start.
Eventually it got to the point that I could only get a flash out of the lights and as you can guess it would not run at all.
So the PCM (or whatever 3 letters you are most comfortable with) is sick.
I know most people are going to either order a new one (I'm not sure there is such a thing) or go to the junkyard and grab a $30 replacement.... unless you have a 4-cylinder.....so.
Research time:
I couldn't find much on repairs for the 96-01 units. the most promising thing I found was this:
https://wranglertjforum.com/threads/how-to-fix-a-no-start-issue-caused-by-a-bad-pcm.13876/
I didn't mention earlier but I installed this particular PCM when I bought the Jeep about 5 years ago. I had the old one so I cracked it open to see what it looked like. Bingo! the exact same problem.
The fix:
I replaced the 3 electrolytic capacitors (220 mF, 25V) taking note of the polarity. I Put thing back together and was rewarded with success. It is alive again.
I do have some photos but I'm not able to post them presently. I suggest you visit the link above for the photos and explanation.
One additional note, the electrolyte that leaks out of the capacitors is corrosive, the black stuff you see in the photos is corrosion of the copper traces on the board. When the juice oozes under the protective gel barrier, it begins to act on the copper below. To extend the life of the unit, the gel (which has become loose), should be removed and the area cleaned up with alcohol and a protective layer applied over the bare layers.
Hope that helps someone, YMMV.
