'77 CJ5 Jeep w/electronic ignition problem

Willy, i have a 75 CJ-5, this was the 1st yr., with the AMC. BID ignition system, do not know what the last yr. was...but AMC issued a recall on the ignition system...bottom line...cut off the electrical connectors, leaving the wires as long as possible..solder the wires, color to color as they came off the connectors, tape w/electrical tape, etc. This should be done with both connectors, i.e.2-wire from distributor, and the 3-wires from the coil...hope this helps, Gene, original owner 75 CJ-5, 258 w efi & hei...

How is the ground strap from the back of the engine to the firewall? If it is rotten, the ignition can lose power.

You could test that with a booster cable. Run it from the battery negative to the firewall or right to the ignition module to see if you get spark.

A bad connection on the starter solenoid can also affect spark for starting. The small side post powers the coil when the starter is turning.

Then those power plugs on the coil itself go bad real easy too. I would have a look at the connections.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Politzanian wrote:

Thanks Gene, for responding. But I'm not quite sure I follow you. Is it that the connectors potentially faulty, so I should remove them from the circuit?

Thanks,

Willy?

Willy, i am repeating the re-call i got from amc, as best as i can from memory...cut out the connectors, solder, tape for water proofing...go jeeping...Gene

The only recall showing on the NHSTA site for a 77 CJ5 is for a bad seal in the 3 speed tranny allowing it to share fluid with the T-case which will lead to total and sudden transmission failure.

And someone was trying to convince me a while ago that they do share fluids... Yup right....

I would sure be running a meter across any of those plugs 'long' before I started hard wiring any parts in. Just put it on Beep or ohms and pin the wires on either side looking for continuity.

Especially seeing as one of the parts is not likely working.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Moggy2cat wrote:

That comes as a surprise to me, as the replacement ignition module I bought last fall for my `79 CJ-5 came with moulded connectors attached.

A couple of quick checks:

Pull the distributor cap and make sure that the shaft is turning with the engine. It probably is, but this is a quick, zero-cost "gas in the tank?" check.

Pull the connector off the coil and check for corrosion. It snaps on, but pull it *carefully*, the plastic gets brittle with heat and time. If you break the latches you can get another, it is a standard Ford part and can be found in the "Help!" racks in larger stores.

Check the voltage at the coil. If you don't have a meter you can get one of those pocket meters at Radio Shack for about 10 bucks -- a real needle meter will be more useful to you for part of this than a digital read-out. The [+] side of the coil is fed full battery power during cranking from the "I" terminal (one of the two smaller posts on the side) on the starter relay, with the key switch in the "run" position it is fed reduced voltage (something like 8 volts or so) through a resistive link (a section of resistive wire loomed into the wiring harness) for OEM harnesses or a ceramic ballast resistor for aftermarket harnesses.

If you aren't seeing battery voltage during cranking check the connection at the starter relay.

If you aren't seeing something like 8 volts at the coil with the keyswitch in the "on" position there's a problem someplace between the coil and the ignition switch. Places to check: The connections to the resistive link (in the harness someplace along the firewall, the insulation feels loose and rubbery when compared to the usual primary wire), the connector block where the harness enters the steering column, the keyswitch itself, and, least likely, the connections at the firewall bulkhead connector.

During cranking the meter should jump around (here's where the needle meter is handy) for each power stroke, this is because the ignition module clamps the line to ground and then opens it to fire the coil. If it doesn't the problem is either the Hall-Effect sensor (replaces old-tech points) in the distributor, it's connector, the ignition module or its connectors.

Boy, it looks like I came to the right place for advice on this. So many helpful suggestions! Thanks to everyone who has responded.

Lee and Mike, I have actually done most of the things you've mentioned (with a needle meter) and it's looking more and more like it's the module. But I will double check the solenoid connections and voltages, etc. Gene's idea of getting rid of the connectors to the ignition module sounds promising because I recall now one time when it wouldn't start, and just by wiggling those wires, it did start.

Fortunately, this is my "working out back" jeep and not my everyday transportation, so I've got time to mess around with with it.

I'll report back here to let you guys know how it turned out.

Thanks again for all your help,

Willy

Just to follow up on this, and to thank you guys again for your help...

I got it running! I can't be sure exactly what the problem was, except that it definitely wasn't the electronics module. My feeling is that it was probably those connectors to the module, which I cut out and soldered the wires as Gene suggested. But while I was at it, I also replaced the coil and some distributor innards. I know, I should have done it one step at a time just to know for sure what the problem was, but I found myself at the parts store and decided, what the heck, it could only help.

Now I can finally fetch that firewood I stacked up on the hill last fall.

So thanks again for the advice. ¶|;-D

. . ... Willy

Whoever sent you after the connectors was right on the money. These things used an early analog breakerless system and the common problem was stalling, caused by momentary opens in the harness connectors.

Thanks for getting back to the group, and I'm glad you got it going.

[snip electronic ignition troubleshooting suggestions] [snip]