ignition failure - 88 GW

[fulsizjeep]

While I was in Las Cruces 2 weeks ago, I had electrical nightmares that killed the ignition on the trail. The orange "key on" power wire coming off the oil pressure switch for the electric choke was melted all the way to the firewall. This fried a coil and at least 2 ignition modules. It appears the melted wire had shorted to the yellow wire that goes to the coil and the light blue wire that goes between the dizzy and ignition module. The yellow coil wire uses a stretch of resistor wire for it's power feed (older models used a ballast resistor) that drops the voltage down for the coil. So the coil got full battery power during the melt down causing the coil failure and the light blue wire between the dizzy and ignition module causing module failure. So, the problem was twofold and was a PITA to trouble shoot on the trail without a wiring diagram.



During the trail fix, we got the offensive orange wire removed up to the firewall since none of the accessories it powered are being used any more and pulled the melted wires apart. The oil pressure switch the orange wire was attached to is shorted causing the whole problem. I was able to drive home 540 miles after that mess.

Today I confirmed this orange wire is indeed melted all the way to the ignition switch and the wire bundle under the dash is compromised. The ignition switch is burnt inside as well. I am darn glad I did not have a dash or engine fire from the short. Looks like I will have to drop the steering column to get to the wiring for closer inspection and repair.

what a deal...

[710 Burner]

Wow. That is kinda unusual.

[HOOT]

WOW .. Good save and glad you were able to get it back home without a meltdown.

I was asked at work just the other day how I could take a risk in dragging my old Jeep out there to Ouray for a meet. After a brief razzing on me not getting my own Jeep on the mountain yet, my reply was; Because the guys I wheel with know these rigs well and some have built them from ground up I fear no breakdown. It's the motorcycles I fear .

Hope Wally feels better soon

[bigun]

Wow I hope you saved a harness or 2 from the rigs you have parted out

[fulsizjeep]

Thanks. I thought that oil pressure switch was to kill the ignition if engine lost pressure. I studied two different wiring diagrams before digging in to it. Wrong, it is for choke power. It shorted, big as day. We have lots of wire saved from parts rigs. I need to get some heat shrink, loom and some other electrical supplies. I also realized this Jeep has had some repairs before my time. The wiring to the alternator has been redone. Oh, and the reason it quit charging on the way home was the 2 wire plug popped out of the alternator. Yeah, it is time to touch lots of wire.

Since 2002, I have been starting it with a push button switch hot wired to starter after the front drive shaft sheared off and ripped the wiring off the tranny and tcase. No neutral safety. I fixed that POS today and can start it with the key again.

[janie]

Glad you made it home without further issue Flint. Wiring................put on your patience cap

One other thought. You sure you wanna put used wiring in Wally?

[fulsizjeep]

What I save from the scrapper is the stuff under the dash and inside the cabin that has not been exposed to the elements. It is good for repairs like this. I plan to replace the ignition switch and run a new power feed from where the orange wire was connected and use it to power the Jacobs and eventually a HEI. I like the 1 wire approach. The HEI unit Krista ordered from Zack is going in Phoebe. That Jeep has also had ignition challenges over the years. That's the way momma wants it and since she jumped through hoops to get the HEI, I am compliant.

[SVO42]

Maybe I transferred some bad ignition karma from my dad's Jeep to yours when we made it to Ouray this year.

If it was me, I'd ditch most of the wiring, esp. since fire did part of that for you, get a points distributor and go with a Pertronix Ignitor. If this '88 of my dad's (not the '87 that didn't make it to Ouray) has any ignition failures that's what's going to happen with it.

Just remember with wiring, be patient and use a digital multimeter and triple check everything. Good luck!

[FSJ Guy]

Yikes Flint!

This wire seems to be an Achille's Hill of FSJ's (I know, one of many!)

Mine also crapped out on me and was the cause of many a headache. Twice, it shorted out and flew fusible links. Then it decided to slowly melt my ignition switch.

You can trace it back from the ignition switch to the heater fuse on the fuse box. Replace that portion of the wire, and as you mentioned, the rest of it goes to the choke heater circuit. That wire ALSO powers the anti-diesel solenoid on the carb.

As you found out, it is NOT fused at all except for the fusible link which will also take out the rest of the ignition system and leave you dead in the water.

When I finally repaired mine, I found that my alternator suddenly worked AS IT SHOULD. It no longer dropped in voltage when I had the A/C or heater fans running.

[NVJEEPER]

What timing I was trying to figure out why my electric choke was not getting power and...HUH...powered from the sending unit I was wanting to ask on here, but my Wag seems to be an Oddball I have no choke...the HEI is great, pump it and it will lite off. I left the wire off.
I now have more 710 psi too(still 0 @ idle warm ). I wanted to hook my electric choke to the driving light switch...no power there either. I don't need no high amp alternator, just keep loosing the lode.

[andy d]

I used parts from 3 different wiring harnesses, and new loom to re-hab the new 88's engine bay during the Great engine transplant of '03. With the exception of a fried coil wire, it has held up pretty well. I am not impressed by AMC's wiring or Chryco's. 20 odd yrs down the road, no electric calamity would surprise me.

[grand_wag_85]

When the little yellow wire to the voltage regulator went out on my '76 it disabled the entire ignition, fried 2 pickup modules and I could not figure out why. As long as your HEI doesn't burst into flames like mine did it is definately the way to go!