1964 CJ5 F-Head 134 Engine Problems

Hi Everyone,

My F-head is having some problems and I can't seem to figure out what is wrong. It will run decent for 30 seconds, then run like it is missing and running on one or two cylinders. I have changed plugs, cap, rotor, plug wires, coil, pulled out the distributor and had it apart and put back in a few times. The best it will do is run decent for a very short time and then its back to missing/running like it is missing. It seems to be getting enough spark and gas.

It ran decent one time when I put it away, but the next day as soon as I started it it was back to running like it is missing.

Any ideas?

Any help is apprieciated.

 

what about the points and condenser? you mentioned all the electricals of the ignition except those key items. Are you sure your points are good? The condenser good? Dwell set right? Timing set right?

 

I drained the gas tank and put in fresh gas.

Points and condenser are new (I have around 6 new sets), dwell and timing are right. Unless I screwed up setting them that is.

This has been an ongoing problem for the last year or so, and I have been trying everything over and over.

 

Looks like one maybe 2 cylinders it is running on.

The exhaust isn't plugged.

It has the vac wipers, I think they were switched over to electric though. I will have to take a look again tomarrow.

 

Distributor bearings sloppy? If they are, it *could* add to the trouble....

 

something else to check
my 59 wase acting like that and when i looked under the hood at night i could see sparks arount the base do the dist, where it fits into the block. i cleaned and tightened the dist and it smothed out.

 

Are you sure? I mean, I was asking if you've checked each wire to see if it's sparking or if it's intermittent on each cylinder, etc.

When it is running I pull each plug wire, one at a time. The motor runs the same when I pull off 1-3 plug wires. If the last one or two are pulled it is basically done running or runs worse. I have also pulled each and checked to see if the the plug is firing.

I haven't checked the distributor bearings.

I will check the vac lines and wipers. I compression tested it, each cylinder tests the same and is in a good range. Sometimes it starts and runs decent for a short while then runs poorly, and sometimes it is doesn't even want to start and runs poorly when it eventually does start.

The plug wires are new, I have 2 sets. I swap them around to see if it helps.

It's been about 3 weeks to a month since I ran it, so all this is off the top of my head. I mess with it so long then get frustrated and take a break from it. I will check it out this week and try some of the things that were said and see what happens.

 

Have you checked the valve adjustment? If they were way off running for 30 seconds could be enough to cause them to stop closing. I am assuming you see a good spark from the plug wires on 1 and 3 when you remove them.

Kevin

 

Check the vacuum system real close too. I think not only is there a vacuum hose going from the fuel pump to the wipers, but another from the pump to the PCV valve, then on to the intake manifold, right? Start at the intake manifold and make sure nothing's loose, broken or cracked. IIRC, aren't those copper lines from the pump to the intake, with a short rubber hose coupler to the pump, and couldn't something be cracked or broken?

I have this old AC vacuum pump, and it shows both vacuum fittings looped together. Don't ask me what vintage it's off of, but I think it was a '65.

Of course, if you have a pump like this and loop it, the intake will still be sucking through the lines to the PCV and the fitting to the pump, so you'd have to plug the end of the line and still make sure there's no leaks going back to the intake manifold.

 

Looks like someone is bypassing the vacuum pump on that one.

If you have been changed to electric wipers, then disconnect the line from the pump to the t that goes to the pcv valve and the carb. Plug the tee where you remove the line from. When was the last time you cleaned the aircleaner? Is the tube from the aircleaner to the carb in good shape? Timing off any? :hurrican:

 

check air cleaner for mice nest