ignition help please

chadamog · 03-05-2006, 09:01 PM

I have an 84 with the 258, electronic ignition in the distributor. The problem started after a Christmas trip. Before that, jeep ran like a champ. Now it won't start at all. I have replaced the wires, coil and spark plugs, checked the connections and confirmed spark (albeit week) at the plugs. When the starter is engaged, it tries and tries, but no actual ignition. Every once in a while after a day or two of sitting, I try again just for kicks and we might get a start, but it won't run longer than a few seconds. I have also checked hoses and any and all other connections that I can think of. As I'll be returning to school full time within the a year, my plan is to have my jeep back up and running with the upgrades that I would like to have done before I sell my car so that I have money for school. I could never sell my jeep, even if it gets a little sick. Any ideas or suggestions would be helpful, I know there are alot of spark issues around the net as I've been looking around for a couple weeks now, but nothing has worked so far. Hoping the experts can help!
Chad

jooper84 · 03-05-2006, 09:18 PM

I'm no expert, but if you've still got the emissions control module on the driver's fender, check your wires there... and replace it if all the wires are solid. That's where I'd start. I'll see what else I can think of.

Geer_hed · 03-05-2006, 09:43 PM

If you're getting spark, then the ignition module might not be the issue, although it is the usual suspect. OEM Jeep spark wasn't very hot to begin with, so you might still be getting the right amount of spark if you're just comparing it to other vehicles. However, a dying ignition module certainly could cooperate with the pickup coil and just send weak spark, which would in turn complicate start up.

Given that you've replaced the ignition coil, wires, and have successfully tested spark, are you getting fuel to the carb? Is your choke fully engaged and not backing off any?

Test spark on more than one plug too, just to see if the results are the same and that the rotor button is doing what it should be doing. Also, are all your wire connections associated with the ignition circuit (module, coil, pickup, etc) clean? Try to eliminate resistance issues where they may arise.

The first thing I would do with a good spark test - even if the spark appears weak - is confirm good fuel to the carb. The weak spark may be a bigger issue down the road, but for now, it's not as big a diagnostic concern as no fuel.

Just some thoughts....

**mxg342** · 03-06-2006, 06:57 AM

Before you try to start it the next time take off the air cleaner and dump a couple of tablespoons of gas down the Carb. If it fires right up you more than likely have a fuel/carb problem.

jeffs73 · 03-06-2006, 08:48 AM

I had a similar problem with my cj-5 a few weeks ago. Turns out it was the fuel pump. Make sure you are getting gas to the carb, if not it may be the pump, or something clogging the fuel line.

chadamog · 03-06-2006, 12:43 PM

I forgot to mention that I checked the fuel line as well. The pump works great, replaced the fuel filter and even checked, replaced and treated the fuel in the tank. Haven't had a chance to dump any fuel directly into the carb yet though. I tried spraying starter fluid down there the other day, but got nothing. Would try it today, but it's raining and the jeep is covered under a tarp as I had the top off. Thanks for the suggestions, I'll have to look at the emmision controls as well to see if there is anything that I might be able to clean up. Anyone know if the Nutter bypass might work for this instance? Thanks for the info
Chad

jooper84 · 03-06-2006, 02:28 PM

I don't think the nutter will be much help here. It doesn't bypass the ecm, it bypasses the computer in the dash. If you're still running a Carter BBD and aren't in a emissions controlled area, a nutter will let you clean up a lot of potential problems but, the problem you're having right now probably isn't one of them.

Mine is an 84 too. I'll bet dollars to donuts that it's the ecm. When I had a similiar problem I swapped in a new fuel pump, ignition coil, cap, and wires before finding a wire on the ecm that was ripped through. It was a cheap fix at less than $20.

Geer_hed · 03-06-2006, 04:55 PM

Ok so if starter fluid didn't do it, and you're still getting a consistent - albeit weak - spark, look at your ignition module like Jooper is mentioning. You just needed to get fuel out of the way first...

If it's not the ignition module, then timing may come in to play. From there, goofy silly crap starts becoming more suspect...

03-05-2006, 09:43 PM	#3
Geer_hed Registered User Join Date: Nov 2003 Location: Richmond, VA Posts: 2,226 Profile Gallery Classifieds My Jeeps	If you're getting spark, then the ignition module might not be the issue, although it is the usual suspect. OEM Jeep spark wasn't very hot to begin with, so you might still be getting the right amount of spark if you're just comparing it to other vehicles. However, a dying ignition module certainly could cooperate with the pickup coil and just send weak spark, which would in turn complicate start up. Given that you've replaced the ignition coil, wires, and have successfully tested spark, are you getting fuel to the carb? Is your choke fully engaged and not backing off any? Test spark on more than one plug too, just to see if the results are the same and that the rotor button is doing what it should be doing. Also, are all your wire connections associated with the ignition circuit (module, coil, pickup, etc) clean? Try to eliminate resistance issues where they may arise. The first thing I would do with a good spark test - even if the spark appears weak - is confirm good fuel to the carb. The weak spark may be a bigger issue down the road, but for now, it's not as big a diagnostic concern as no fuel. Just some thoughts.... __________________ [center][color=black][b]85 CJ7 / 258 / T176 / Dana 30/ AMC 20[/b][/color] [url=http://www.geocities.com/cantwait_forviolence/]My Online Dumping Ground[/url][/center]

03-06-2006, 04:55 PM	#8
Geer_hed Registered User Join Date: Nov 2003 Location: Richmond, VA Posts: 2,226 Profile Gallery Classifieds My Jeeps	Ok so if starter fluid didn't do it, and you're still getting a consistent - albeit weak - spark, look at your ignition module like Jooper is mentioning. You just needed to get fuel out of the way first... If it's not the ignition module, then timing may come in to play. From there, goofy silly crap starts becoming more suspect... __________________ [center][color=black][b]85 CJ7 / 258 / T176 / Dana 30/ AMC 20[/b][/color] [url=http://www.geocities.com/cantwait_forviolence/]My Online Dumping Ground[/url][/center]

03-05-2006, 09:18 PM	#2
jooper84 Registered User Join Date: Dec 2005 Location: Lincoln NE Posts: 226 Profile Gallery Classifieds My Jeeps	I'm no expert, but if you've still got the emissions control module on the driver's fender, check your wires there... and replace it if all the wires are solid. That's where I'd start. I'll see what else I can think of.

03-06-2006, 08:48 AM	#5
jeffs73 Registered User Join Date: Mar 2006 Posts: 2 Profile Gallery Classifieds My Jeeps	I had a similar problem with my cj-5 a few weeks ago. Turns out it was the fuel pump. Make sure you are getting gas to the carb, if not it may be the pump, or something clogging the fuel line.

03-06-2006, 12:43 PM	#6
chadamog Registered User Join Date: Mar 2006 Posts: 2 Profile Gallery Classifieds My Jeeps	I forgot to mention that I checked the fuel line as well. The pump works great, replaced the fuel filter and even checked, replaced and treated the fuel in the tank. Haven't had a chance to dump any fuel directly into the carb yet though. I tried spraying starter fluid down there the other day, but got nothing. Would try it today, but it's raining and the jeep is covered under a tarp as I had the top off. Thanks for the suggestions, I'll have to look at the emmision controls as well to see if there is anything that I might be able to clean up. Anyone know if the Nutter bypass might work for this instance? Thanks for the info Chad

03-06-2006, 02:28 PM	#7
jooper84 Registered User Join Date: Dec 2005 Location: Lincoln NE Posts: 226 Profile Gallery Classifieds My Jeeps	I don't think the nutter will be much help here. It doesn't bypass the ecm, it bypasses the computer in the dash. If you're still running a Carter BBD and aren't in a emissions controlled area, a nutter will let you clean up a lot of potential problems but, the problem you're having right now probably isn't one of them. Mine is an 84 too. I'll bet dollars to donuts that it's the ecm. When I had a similiar problem I swapped in a new fuel pump, ignition coil, cap, and wires before finding a wire on the ecm that was ripped through. It was a cheap fix at less than $20.