CJ5 stalling problem

First thing is to check the braided ground strap between the engine and frame. If that's corroded away you will have all sorts of problems.

Are you fuel injected or carb? For a carb that can be crud buildup or a big air leak around the gasket. (spraying carb cleaner around the base of the carb will tell you quickly if you have a problem)

Stalling on an injector system can be a clogged fuel filter. Although it usually just kills your top end speed or gives you lean pinging at wide open throttle.

I need to learn how to read. :)

How long has it been since you rebuilt or had the carb rebuilt?

Never had the carb rebuilt, it's "new" (

One word of caution. Learned this on my chevy. If you overtighten the bolts you can warp the ears. That causes leaks. A flat glass table and some 800 grit will even things out again. I also never reuse gaskets. They are cheap. I don't use any gasket sealer, but some folks use a smear (think smudge on glass) of permatex copper. A super thin coat around the edges.

Doesn't seem to have helped. Stalled once on the way out tonight, twice on the way back. Granted this is better than the 4 times it stalled on the way home from work this afternoon, but still more than the 0 I'd prefer.

A few more thoughts.

How's the idle RPM?

Is the choke sticking or electric choke malfunctioning?

Are there any hoses (break booster hose is a good one) that have cracks? The carb-cleaner test works well on those. Just spray and listen for a stammer.

Also check the engine ground strap. Those tend to rot out. Running a good thick wire between a good bolt (free of paint) on the engine and the frame (or main ground bolt) is fairly easy. Standard 12AWG wire can be used in a pinch, but the actual ground strap is more beefy. If you measure Ohms between the engine and chassis ground (engine off) it should be very low. 1-2 Ohms or so. With the engine on and using milivolts you shouldn't see any voltage between the engine and ground.

The only other thing I can think of is more related to the old

The standard night check for sparks along the wires and if you have any cracked plugs.

Remove, clean, reinstall all electical connectors including the battery posts. I've had times when the battery posts were broken and fell off in my hands.

Fairly easy test for spark power.

You don't narrow it down much. Does it stall at idle, letting off the gas at speed, die at any particular RPM? This sounds like an electrical problem and - as best as I remember - there is nothing electrical about that carb except the choke. Does it matter how long you let it sit before restarting? If it takes a few minutes to come back alive, check for spark as you crank - a bad coil or limit resistor can cause this.

Doug's idea of the ground strap is one of the best starting points. Connect a jumper cable between the negative post and the engine (careful where the cable flops under the hood) and see if that helps. If it does, then begin at the battery and start cleaning grounds. While you are in there, inspect all the wires around the ignition for chafing or breaks.

As others have mentioned, check that tub ground first.

Your ignition module way down on the inner drivers side fender under the washer bottle can fail like that. If you do go for a replacement get any type except a Wells unit, most Wells come dead in the box.

Do you still have the computer running the timing? The computer can also cause stalling like that when it is going bad and is real easy to take out or bypass. If it is still in there, it is in 'limp' mode which affects the timing advance.

A distributor pickup coil can also fail intermittently, mine went bad at

Mike

I didn't limit it much because it's not limited much. It will stall just as much at a red light as it will when accelerating or cruising. About the only other thing I can think to add is the electrical devices (radio) don't shut off when it stalls, so it's not a complete loss of electric.

I'll check all the suggestions I can this evening and report back.

after about an hour under the hood this afternoon, i don't feel any closer to a solution. checked various volt/ohm readings on the ignition module and coil both while idle and running, all are as expected. as are the volt/ohm readings for the ground strap.

i did find a vacuum line that didn't appear to go anywhere on the passenger side. couldn't find anywhere where it might have gone to, so i plugged it. had little to no effect on the engine idle. i also learned i have no windshield washer reservoir (hey, i live in the desert and only drive short distances, i've never had a need to wash my windshield other than at a gas station). and while i did find the wiring for the pickup coil (which until today i never heard of), i have no idea how to check the ohms on this.

since the ignition control module is cheap and easy to replace, i'm leaning towards just replacing it and seeing if it works. thoughts?

i'm assuming that

Follow it back. Might be the windshield washer hose.

The pickup coil can be tested with a low voltage test light or scope. It's not an easy thing to test. Basically it provides pulses that tell the control module when to fire the spark. Older vehicles used points to do roughly the same thing.

The "shotgun aproach" works for me sometimes. Worst case you have a spare.

Same as this

it's definitely a vacuum line. and it's on the wrong side of the engine to go to the (absent) washer fluid reservoir. it's short, maybe

Those ICMs got cheaper over time. I would swap that out to eliminate it as a possibility.

Like Doug said, all the electronics are buried in that 'potting compound' so they are ostensibly protected. It makes it into a one-piece throw-away part that is unfixable, just replaceable. I am surprised that it is so cheap now... Tomes

Anogher guess, vacuum advance? That would mess with your timing and cause problems.

Check the distributor for a vacuum line and maybe under the air filter for an open nipple or give us a link to a photo of it.

i did find the

The orange and purple wires will show between 400 and 800 ohms between them on a multimeter if it is good. The wires can also crack on them inside the distributor cap.

since the ignition control module is cheap and easy to replace, i'm

Looks like the right part. Mike

Anogher guess, vacuum advance? That would mess with your timing and cause problems.

I replaced the ignition control module on Sunday afternoon. Been on the road 4 times since then, and not a single stall. Normally it would have stalled 3-6 times on those trips. At this point, I think I got lucky with the shotgun approach (to use DougW's term). Thanks for the help and suggestions everyone.

Glad to hear that's what it was. Nothing more fustrating than a glitch that can't be found.