Jeep only runs in "start"

[mbcj7]

I brought my jeep home, and with a little basic cleaning of fuel lines etc, I was able to get her fired up. A little more cleaning and she would idle. Very roughly, but idle. Rebuild the carb overlooking the accelerator pump, and it idled way better but would starve for fuel, stumble and die when revved. Pulled and rebuilt the carb again (including accelerator pump) and it wouldn't idle at all. Replaced the carb with a brand new rebuilt one, and it will only run with the key in the "start" position.
I've replaced the dist cap, rotor, plugs, ICU, ignition switch, and coil and still will only run in start.
I've researched and keep seeing this could be a ballast resistor issue, last night I located what I think is the resistor wire and ran another wire in parallel with it effectively bypassing the resistor wire and still no change.
It was getting late and was dark, so I gave up for the evening, but am stumped right now.
What else should I try. I'm getting anxious to get back on the road.

This is in my 83 cj with the AMC 258 i6 / 4.2l

I read something about a "nutter bypass". I'd like to do the bypass, but would like to have it running before I delve into trying to make it run better

 

[JR74CJ5]

Not positive I'm understanding the problem fully...

If it is that the ignition switch needs to be in the start position, i would venture to guess the ignition switch is bad. The key shouldn't "stay" in the start position... ?? It should spring back. If thats the case, the switch is bad... Otherwise, possibly a wiring issue on the starter solenoid (maybe a mix-up while reinstalling new parts under there?) or back of ignition switch, though i still can't get around the "start" position part...

Could be just me, but maybe some further clarification...

 

[mbcj7]

Not positive I'm understanding the problem fully...

If it is that the ignition switch needs to be in the start position, i would venture to guess the ignition switch is bad. The key shouldn't "stay" in the start position... ?? It should spring back. If thats the case, the switch is bad... Otherwise, possibly a wiring issue on the starter solenoid (maybe a mix-up while reinstalling new parts under there?) or back of ignition switch, though i still can't get around the "start" position part...

Could be just me, but maybe some further clarification...

Sorry for the bad explanation. Let me try again.

the key does spring back to the run position. The jeep was starting and idling like it should, a little rough, but would idle. I rebuilt the carb and it would idle better, but when you tried to rev it, it would starve for fuel and die, but re-start ok.
I pulled the carb and rebuilt the accelerator pump, and this is where my electrical gremlin reared his head.
After putting the carb back on, it would try to start, sometimes backfire, but never run. At this point I ordered a re-built carb for it. It came in, and I slapped it on real quick.
Now when I try to start it, it fires, however as soon as you release the key and it returns to the "run position" (as it should) the jeep dies.
I checked my voltage at the coil in "run" and it is 7v.
I did some brainstorming and figured the ignition switch must be bad.
Replaced the switch, same problem. So I replaced the coil. Same problem, I replaced the ICM. Same problem.

So to summarize, the key cylinder is doing as it should, the ignition system somehow is not.

I searched and kept seeing something about a ballast resistor, but tried bypassing it last night, and it still will not run in "run" but will fire up in "start"

 

[amcjeepman]

Try changing the position of ignition switch on the steering column, it will actually move up and down a little and can be enough to affect the start/crank and run position. I am talking about he switch on the lower portion of the column near the firewall, not the key switch.

 

[fzsk4p]

I understand what you are describing. Once the key returns to the "normal" run position the engine dies. Suspect the starter is helping it to stay running.

First off I will say that I am pretty knowledgeable on electrical systems. But not on 83 CJ7 `s. So lets poke at this.

7 volts at the coil is not enough to create much of a spark. Should be around 9.

IF there is in fact a ballast resistor you bypassing it should have bumped up the coil voltage.

Check this out
basic wiring for '81 CJ7 Bottom of page one it starts to get informative.

basic wiring for '81 CJ7 page 2

Jeep CJ Wiring Diagram - Jeep Year 1979

 

[mbcj7]

Well, I guess a 9 year nap makes all kinds of stuff decide to die shortly after awaking. I read up on the "nutter bypass" and although a lot of things state its for 84 and up, I had the ECM under the dash, so last night after work, and dealing with all my puppies, I twisted a couple of 16ga wires together, and spliced them on both ends. Hopped in the Jeep, turned the key, and climbed out after it was running. Ran good, but idled a little low. Ran till I killed it turning the wheel and the steering pump lugged it down. Cranked back up, bumped the idle up a hair, and it ran until I noticed flames under the hood. Which was good timing cause the wife was coming out to tell me shut it down, when, her sentence was interrupted with "thats too lout to be.....Your Jeeps on fire"

 

[hole]

Glad to hear she's running again but fire is bad news. Hope thats an easy fix

 

[mbcj7]

Yea, fires arent good. Hopefully all the wires and other things that burnt are coming out after the nutter bypass anyway. Ill try and start this evening, but Ill be off next week with two helpers, so hopefully I can get a few of these other projects knocked out the way

 

[markinnevada]

Hey I'm not new to electricity either, but I'm new to 83cj-7s, as I just bought one from my daughters boyfriend for a song. A cheap song at that. Similar problems arose and I did jump the coil directly to the battery which you discovered is close by. I also found that the switch on the column wasn't kicking the starter back out after I started it. The switch was loose and was never installed per the directions on the box. My first try mine would only run in the start position, but that was the location of the switch was was simple to fix. Make sure you remove all the brackets from the steering column so you can reach in and remove the two wiring clips or you'll pull a few out by mistake...I'm not saying I did that, I'm not saying I didn't!!! Clean the switch first before thinking about buying another, and remember to never throw anything away.......ever! Found that if I cleaned some contacts and scraped some schmutz off everything I got nearly 10 volts to the coil. I gained a few more than needed. But I hooked a clean positive right to the battery with a clip and went from there. Hey I can diagnose a problem with a 425,000v distribution line so I figured this jeep should be simple. It was, but took some bathroom time with the book and a big white board to figure out where everything went. It runs great now, and we smog here in Reno so I had to be creative with the air-pulse to make it look like it hadn't been monkeyed with. ( let me know if you need some help there). My maybe future son-in-law thought duck tape and bailing wire was good for everything, and so after a few months of tinkering and replacing some simple stuff it's good enough to be a daily driver. Won't replace the diesel p.u. but it is fun. I've got two others to eventually fix so this was a good project before I try a frame up on a 55 willys and a 68 CJ5 v-8er that I've had stored in the garage since ......uhhhhhh forever.
Best, Mark

 

[mechjono]

Had the same problem with mine, after a bit of frustration found that two things caused my problem. One was the big plug at the firewall. One of the spade connectors was gummed up with the tar that they put to seal off the connector. The other is that the coil gets full 12 volts when the switch is in the start position and then gets a lower (resisted) voltage after the switch is released. That is what the red wire does on the solenoid. The red wire ties into the power side of the coil. But it surely could be your switch or the plug under the steering column.