Faulty Ignition System?

Jackson LeBlanc

Jackson LeBlanc

New Member
Joined
Jun 27, 2023
Messages
19
Location
Lake Charles, Louisiana
Hey guys, a couple weeks ago my jeep went out with an electrical issue. It’s an ‘87 L6 Carb. I’ve replaced the ignition coil, ignition coil connector, and the ECM. The thing I’m seeing is when I turn the key, it cranks, but the tachometer doesn’t jump up and down like it’s supposed to. When it first happened it smelled like rubber which would point to the alternator. Also getting battery checked as well as the alternator. It doesn’t run by the way. I got it to fire and run with jumper cables, but when I took them off it died making me think it’s the alternator. Last thing to note is that it doesn’t need a crank position sensor. Thanks.
 
So just an update, we've decided to rebuild the wiring harness, we went ahead and replaced the starter solenoid, ignition coil, and the Jeep has a Nutter bypass done to it. If this doesn't fix the problem, I'm assuming the problem is the pickup coil in the distributor, or it is a relay. However, I think it is the wiring harness because me and my dad went through some wires, and they were melted together, and copper was exposed in multiple places. Its frustrating because the wires that were bad lead to things that aren't even apart of the jeep anymore. (Electric choke wire, relay wire etc..) Let me know what y'all think.
 
The coil was getting 4 volts which suggests that the wiring is bad. The previous owner did do work on this engine and he did the nutter bypass weird. He decided to duct tape exposed wires together which I'm sure caused the problem. One of the wires that was bad went to the alternator so now we're getting the alternator tested. Wiring harness seems to be the issue because not all the wires that need current are getting current. Thank you for your help and I have the service manual at home and the diagnosis matches up with whats been going on. i will look more into the resistor given but I don't think the resistor has a purpose anymore given the nutter bypass was done and the resistor being spoken of leads to the electric choke/ICM I'm assuming. Keep in mind a non-computer-controlled carburetor is on there as the ECM is no longer wired anywhere to the electric system in the jeep.
 
I ripped the entire harness out of my 89 and not looking back. The computer controlled carbs were a half assed stop gap meassure to appease the EPA that should never have been done. I can remember the feasco in the 80’s with auto dealerships pulling their hair out trying to get them to work properly. I refuse to maintain something that is a piss poor design. When I got this Jeep it had so much wiring that no longer did anything I decided to make my own. The new harness is getting everything that it needs, and nothing that it doesn’t.
 
Jackson LeBlanc said:
The coil was getting 4 volts which suggests that the wiring is bad. The previous owner did do work on this engine and he did the nutter bypass weird. He decided to duct tape exposed wires together which I'm sure caused the problem. One of the wires that was bad went to the alternator so now we're getting the alternator tested. Wiring harness seems to be the issue because not all the wires that need current are getting current. Thank you for your help and I have the service manual at home and the diagnosis matches up with whats been going on. i will look more into the resistor given but I don't think the resistor has a purpose anymore given the nutter bypass was done and the resistor being spoken of leads to the electric choke/ICM I'm assuming. Keep in mind a non-computer-controlled carburetor is on there as the ECM is no longer wired anywhere to the electric system in the jeep.
Click to expand...
this

https://Jeep Forum/threads/how-to-nutter-bypass.522262/
 
After a lot of trial and error we figured out the connector we had replaced that connected the coil and distributor to the rest of the spark system was not getting contact which means the ignition coil was not making enough voltage to send off, meaning it made no spark. Part of the issue was the wiring harness, the other was the connector. We are fixing it soon and jeep will be back on the road.
 
ytradio said:
I ripped the entire harness out of my 89 and not looking back. The computer controlled carbs were a half assed stop gap meassure to appease the EPA that should never have been done. I can remember the feasco in the 80’s with auto dealerships pulling their hair out trying to get them to work properly. I refuse to maintain something that is a piss poor design. When I got this Jeep it had so much wiring that no longer did anything I decided to make my own. The new harness is getting everything that it needs, and nothing that it doesn’t.
Click to expand...
Exactly what we did. When we got the jeep it had the bypass done to it so a new carb was already on there and that piece of junk old one was somewhere in a junk yard. When we did the wiring rebuild everything it needed we kept and everything it didn't we threw out and to our surprise the majority of the wiring we didn't even need.
 
Jackson LeBlanc said:
Exactly what we did. When we got the jeep it had the bypass done to it so a new carb was already on there and that piece of junk old one was somewhere in a junk yard. When we did the wiring rebuild everything it needed we kept and everything it didn't we threw out and to our surprise the majority of the wiring we didn't even need.
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Wish I had taken more pictures of the wiring, especially what was inside the driver’s compartment. It had a push to start button located where the push button to open the console was at. The wire to it was tight and the console couldn’t be opened. Enough free hanging wires from under the dash that I have no doubt that installing a battery would have resulted in a fire. I am sure part of the mess under the hood was the Nutter bypass but who knows, there was plenty more that no longer did anything. I am sure everyone here would have found it hilarious.
 
Got the Jeep running, I'd like to keep this thread open for a simple issue. When it started running the brakes were basically non-existant. We had done work on them and I'm almost positive that the issue is fluid related. I put new fluid into the brake master cylinder this morning and pumped the pedal so the fluid would go throughout the system and it started getting better. Should I keep adding fluid until the pedal stiffens further?
 
Jackson LeBlanc said:
Got the Jeep running, I'd like to keep this thread open for a simple issue. When it started running the brakes were basically non-existant. We had done work on them and I'm almost positive that the issue is fluid related. I put new fluid into the brake master cylinder this morning and pumped the pedal so the fluid would go throughout the system and it started getting better. Should I keep adding fluid until the pedal stiffens further?
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I would bleed the brakes and see if there is fluid loss. My 95 had a caliper that was leaking and every once in a while the brakes would go spongey.
 
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