Cj5 258 6 Just Stops Running

Mine does have the two outlets on the fuel filter. I'm sure it's not vapor locking. When it cuts off it will still squirt gas I also unhooked the gas feed line and put the end in a glass jar and let it run till the bowl went dry it pumped gas fine. So I'll start checking the ing system next. Thanks for the info.

 

My vote is a failing ignition control module when it gets hot. Let it cool, even for a few moments and engine starts. Do a search on your ignition system on you find countless threads describing your symptoms.

 

And yet people persist in going to electronics for "reliability." Baffles me.

 

Hei was a great improvement over ignition points in 1975, but a lot of people went back to points. I was working in a garage then and saw this firsthand

 

I would guess the ignition module also. Dies , cools off and restarts.

 

I got a new ignition module from Auto zone put it on wouldn't start at all same number of wires same color so I took it back traded for another one same thing put old one back on fired right up. So back to square one about ready to roll it down a hill !!!

 

The Motorcraft junk that AMC ran was an attempt to do anything possible to get rid of breaker point ignitions. GM just happened to figure it out with the HEI long before the other OEMs did.

 

the '74-77 cjs with the 258 ran prestolite junk for distributors; not sure if prestolite was made by motorcraft, but i believe motorcraft came later (78-onward).

 

Every ignition system AMC ever ran was junk. Which is the biggest reason why I dislike AMC motors so much.

 

Prestolite is Prestolite. Used '75-77 only in AMC & Jeep. It uses a different physical principle from every other electronic ignition. It's called the BID (Breakerless Inductive System) - read here starting at page 44 http://oljeep.com/gw/76_tsm/Section3.pdf

Starting in 1978, Jeep switched to the Ford Duraspark I ignition system. It uses the same physical principle as the GM HEI, "variable reluctance." Today, everything is either VR or optical.

I think the Motorcraft Duraspark stuff is fine. It's all electrically compatible with the GM HEI, just different packaging: a VR trigger switches a big transistor that switches the coil. You can use a hot coil with the Duraspark system and have a "high energy" system, just like the GM HEI. Ford vs. Chevy.

 

Thanks for the info I'll start testing the ing components hopefully this weekend

 

actually, the BID refers to breakerless inductive discharge, but i'm pretty sure you knew that. fwiw, i eliminated my prestolite BID with a buick hei cap/chevy 250 distributor.

 

as noted in my post above, i also classified the prestolite electronic dist/ign as junk, and switched to a gm hei unit. however, i am a big fan of the 258. good, low rpm useable torque, long service life on a 7-main bearing motor that will take some serious abuse.

 

I think this.

 

If you have the Motorcraft Duraspark ignition module on the fender start there. Check the mounting/ground first. If that is ok then suspect the module. A pisspoor design where the factory built a flexible circuit board, folded it in half, the. Installed in the aluminum finned box. These were problematic back when they were still used on Fords. When a I worked at Ford we found a huge failure rate of these on 4x4 vehicles and higher mileage vehicles. Heat up, lose connection on the circuit board and engine dies. Cools down, reconnects, starts back up.
After working for Ford my boss and I cut a bunch apart and in every instance found connectivity issues with the circuit boards. Either failed or about to.
I respect Timgr but you will never convince me this system is a good substitute for better systems.

Regarding points systems? They fail too and are much more maintenance. Last time I checked capacitors were a common failur point as is wear on the running blocks, corrosion and burning on the contact surfaces of the points, bushing wear in the distributor body, spring for the points weakening, etc. I remember when we had scales to check the spring strength.
No ignition system is perfect but some are much, much better than others.

 

Possibly. In my experience about 15 minutes and $15.

 

PeteL, I do like the simplicity of an old points ignition system. It's what I learned on but I must say I like my distributorless wasted spark ignition system on my jeeps engine. It is an awfully durable system with the only moving part in my system being the crankshaft. The ignition module to the best of my knowledge is 23 years old.

 

Not possibly. Adjustments need maded for wear of the rubbing blocks and contact recession. Simple, yes, but not foolproof and they start degrading immediately on startup.
HEI. $30 for ignition module, 5 minutes to change, and no dwell or ignition timing adjustments to make (I.E. no timing light and no dwell meter or feeler gauges needed).
Everyone has their preference, and no problem there. But let us be honest and see that there are other options that are better for most that don't want to constantly fiddle with their ignition systems.