dzywicki

Did some sleuthing and wrenching. I was getting ~30 ohms on the multimeter, but that was after I moved the Jeep so I could work on it easier. After it cooled down, I swear I was getting more like 3-4. I took the same reading on my 98 and was getting 3.2. My wife added some more info saying every once in awhile, the coolant temp and oil pressure gauge would go really high. I decided to go ahead and swap the alternator. That was less than an hour out and in and ready to go.
Did some revs and a short test drive trying to rev the engine as much as possible. No blown fuse after a short trip. What a pain. I'll remeasure resistance after it sits overnight and it's stone cold. ay need to get an amp guage so I can watch it from inside. The fun of old Jeeps. I wonder what a professional mechanic would do with this situation.

dzywicki

Finally got to recheck resistance this morning. Was reading ~3 ohms. The heat must linger for quite awhile. I am really not sure what else to try at this point. Only other thing I can think of is insulation inside the harness periodically shorting. Seems like ti would show up more frequently if that was the case. If it keeps happening, will go to an amp meter to see what is going on there.

dzywicki

Well, the alternator was not it. Fuse blew again. Next step is disconnect the front sensor, then the rear sensor separately. Also going to figure out how to wire something in the cabin that will show a light or something when the fuse blows to know what/when is causing it. It hasn't blown when I have taken it on test drives but blows when my wife drives it. I hope there is a mechanic critera when deciding if we go to heaven or hell. I have to imagine I have assed the test to relax in heaven. This seems like one of those hell tests.

bluejeep2001

Im an airline mechanic.....we're all going to hell..I think that was written in the job description..lol

Saudade

Well, perhaps when you and your wife go out again together (dinner, shopping, whatever), you should let her drive. If it happens, you may be able to see what was going when it blows.. I'm not suggesting she's doing something wrong, just that witnessing the event yourself can help diagnose the cause. Sometimes, going over speed bumps, up or down driveways, etc., can flex harnesses and blow fuses.

When you had your harness open, did your visually and physically verify the integrity of all the crimps/splices in there?

Once I had an intermittent #3 injector. I'd be driving around just fine, and then suddenly, the engine ran rough, and lost power. I'd pull over, lift the hood and look around to see if something "came off" or any other signs of trouble. I'd see none, drop the hood, start the engine and it's fine. However, this got progressively worse. Bear in mind it's an '88 so no codes. It would "misfire" again, back under the hood, and double check injector connections, make sure the harness didn't hit anything hot and burn through. I finally figured out that moving the harness around often "fixed it". So now I know I have a wiring issue inside the harness. Turns out on a Renix, all FI grounds come together in one big crimped corroded splice wrapped in tape. The #3 injector was barely connected. I ended up replacing all of the FI connectors and ran fresh ground wires further back and did a staggered solder joint to make the bump for the splice smaller. Been running fine ever since.

So if you can, go back and check continuity or voltage and start shifting the harness around. Tug on the splices and see if they hold.