Intermittent ignition cut out.

[nightwalker1500]

I'm new to this site - fairly new to CJs, although I've owned a few in the past and never got around to digging deep into them. I've got a 79 CJ5 , AMC 258 i6 / 4.2l I6, stock ignition module, elec. fuel pump (frame mounted), no neutral safety switch. The engine will cut out occasionally, usually shortly after leaving the house first thing in the morning. Clean cut out with no popping or sputtering; I can kick it into neutral and the engine will fire when the starter is engaged, but the first 1or 2 attempts will not allow the engine to fire when I get off the starter position. The electric fuel pump is running the entire time. Then it will restart and run smoothly for the rest of the day. It seems to be temperature related.
Could this be a signal that the module is getting weak? Has anyone else experienced this?
I appreciate the accumulated knowledge on these threads.

 

[IOPort51]

I would buy a new module if I knew where to get a good one before you are stranded by the side of the road. If the new module helps I would seriously consider a team rush with an MSD module. The major symptom I have experienced is dying and restarting after a minute or two.

You have an electric fuel pump? do you have TBI?? If not, why do you have an electric pump??

I'm new to this site - fairly new to CJs, although I've owned a few in the past and never got around to digging deep into them. I've got a 79 CJ5 , AMC 258 i6 / 4.2l I6, stock ignition module, elec. fuel pump (frame mounted), no neutral safety switch. The engine will cut out occasionally, usually shortly after leaving the house first thing in the morning. Clean cut out with no popping or sputtering; I can kick it into neutral and the engine will fire when the starter is engaged, but the first 1or 2 attempts will not allow the engine to fire when I get off the starter position. The electric fuel pump is running the entire time. Then it will restart and run smoothly for the rest of the day. It seems to be temperature related.
Could this be a signal that the module is getting weak? Has anyone else experienced this?
I appreciate the accumulated knowledge on these threads.

 

[nightwalker1500]

Thanks for the reply, IO. I've been suspecting the module. My CJ had the electric fuel pump when I bought it from the last owner, but the engine has what I think is the original carburetor.
I'm going to pick up a new module and see if that cures the glitch.

Much thanks, IO.

 

[Old Dog]

The electric fuel pump is running the entire time. Then it will restart and run smoothly for the rest of the day. It seems to be temperature related. .

ICM's do act this way before they go out sometimes.
Does your fuel pump always run or does it usually shut off when the pressure builds up?

 

[nightwalker1500]

@ Old Dog
The fuel pump runs continuously, so I know it's not cutting out on me.
I think I'm just going to replace the entire ignition system and take IO's advice and go with Team Rush with an MSD Module. That way, I know I'll have that eliminated if the problem reappears.

 

[Old Dog]

@ Old Dog
The fuel pump runs continuously, so I know it's not cutting out on me.
I think I'm just going to replace the entire ignition system and take IO's advice and go with Team Rush with an MSD Module. That way, I know I'll have that eliminated if the problem reappears.

Taking IO's advice is a good idea.

The elect. pump still has me thinking though, most elect pumps shut off
when they reach a pre-set pressure and than just run intermently to hold that pressure.
Did the PO plumb in somekinda regulator/return line that makes the pump stay on all the time?

 

[Tommy]

I would suspect the fuel pump before the ignition module. It seems to fire fine but not get enough gas to start with. Like Old Dog said, the pump doesn't usually run all the time. I'm not as mechanical as some but in my experience a module usually works or doesn't.

Tommy

 

[jasonmark1993]

Ive never seen a fuel pump that turns on and off. HP systems have a return line and most carbd systems have a bypass pump.

An intermittently failing ignition module can def. happen. Usually when they are heat soaked or otherwise very hot but I suppose they could happen before reaching high temps. Ford had a string of recalls for several years with their TFI modules due to intermittent operation.

 

[nightwalker1500]

The fuel pump has a return line so there's no over pressure problem. The nature of the problem is so intermittent that I have to believe that there is a circuit going open for just a few seconds. After I upgrade the ignition components, we'll see what happens...
I appreciate all the help, here. I'll let you know what the verdict is once the changes have been made.

 

[xena1]

Had the exact same problem with an HEI distributor. After looking at everything, turned out to be the ignition module which would heat up and cut out. Motor restarted and drove fine for awhile until same condition happened.

 

[nightwalker1500]

That's what I think (hope?) I'm dealing with. Funny part is, since I started this thread, my cj hasn't cut out once. I think you guys scared it.

 

[jasonmark1993]

its just waiting until you are in the worst place possible, like an intersection, train tracks,.......

 

[nightwalker1500]

I just wanted to thank everyone for your input. I replaced the Ignition Module and have been all over some of the So. Colorado mountains for the past few days. No cutout, no sputter, better mileage and smoother running. Hope you all have a great one!