Engine stalling

[ALF]

79 CJ7 with a 304. Fires right up and runs great but after awhile on the trail it will just sputter out and die wait a few seconds and it fires right up and is fine. Sometimes it will stall out again almost immediatly other times it wait 10-15 minutes and then cut out again. Any ideas?

 

[AINT SKEERED]

Carb or FI? Cats? Shape of rotor cap and plugs?

 

[kkemp]

Carb or FI? Cats? Shape of rotor cap and plugs?

It's a carb.

Alf, isn't everything on the engine pretty much new? I would tend to think the problem would be in the wiring as in something being loose, or a fuel problem. You mentioned on the trail yesterday that the choke was not hooked up. Is the choke free to change position in the carb? Maybe its closing up on you and making it too rich. I'd make sure that stuff is alright before replacing expensive stuff.

 

[bruzer]

I would have to agree with kkemp, check the easy stuff first before you start replacing the costly things. How many miles are on it? Could it be maybe your fuel filter? I had similier problems with me 4runner when the fuel strainer was starting to clog. But I would check everything else out first before you start thinking about pulling the gas tank though. If you have a bit of miles on it the fuel filter is an easy and cheap thing to think about. Good luck!!

 

[rockreligious]

yep, I would guess that you have water in your gas, plugging up the fuel filter screen, when you let it sit the water settles back into the bottom of the filter allowing gas into the carb. just a guess but Ive had this happen before.

 

[bobdog]

Sounds like vapor lock. Are the gas lines running too close to the exhaust? I would also suspect the ignition module. Is it a duraspark box?

 

[DOSS]

I would say Vapor lock as well... if this only happens when the engine is hot... check where the fuel lines are running all the way back to the tank... Hook up your choke to make sure that isn't a problem as well...
as for water in the tank I have never seen that cause what you are talking about but stick a bottle of seafoam in the tank.. it should stableize the fuel enough that you can run it through .... if that all fails just convert it to propane (don't you trailer that beast?)

 

[rockreligious]

also test the coil. ive had them quit working when hot, spark?

 

[ALF]

yes it is trailered...

The inline fuel filter was resting on the thermostat housing maybe that was heating it up enough to vaper lock it and I fixed the choke. I'm still going to swap out the ignition module and coil and hopefully no more problems for some reason I can't get it to do it in the driveway so i'll find out on the trail?!

 

[ALF]

yes it is trailered...

The inline fuel filter was resting on the thermostat housing maybe that was heating it up enough to vaper lock it and I fixed the choke. I'm still going to swap out the ignition module and coil and hopefully no more problems for some reason I can't get it to do it in the driveway so i'll find out on the trail?!

 

[BCGPER]

Alf, it's vapor lock. 304 poweded CJ's are famous for it. Try insulating your fuel lines from the carb all the way back to the tank. I'm guessing you have dual exhaust, so you're really adding a lot of heat into the gas system from there. Stock CJ's had single exhaust on one side, then the fuel line ran down the other.

An electric pump as close to the tank will also help. You wont need to run it all the time, but when this does happen just flip the pump on and it will fire up in a few seconds.

yes it is trailered...

The inline fuel filter was resting on the thermostat housing maybe that was heating it up enough to vaper lock it and I fixed the choke. I'm still going to swap out the ignition module and coil and hopefully no more problems for some reason I can't get it to do it in the driveway so i'll find out on the trail?!

 

[ALF]

Alf, it's vapor lock. 304 poweded CJ's are famous for it. Try insulating your fuel lines from the carb all the way back to the tank. I'm guessing you have dual exhaust, so you're really adding a lot of heat into the gas system from there. Stock CJ's had single exhaust on one side, then the fuel line ran down the other.

An electric pump as close to the tank will also help. You wont need to run it all the time, but when this does happen just flip the pump on and it will fire up in a few seconds.

As you know I know little about Jeeps...It has a elecric fuel pump on it already and possibly a manual theres what appears to be a manual pump on the front driverside on the engine

What do you suggest to use to insulate the fuel lines?

exhaust is single running between the dtrain and the frame rail on the ds with the fuel line running outside the frame rail on the ds

 

[78mitsu]

which carb is it, does it do it when it's going uphill or downhill on the flat? it could be as simple as an improperly set float level. Give us some more detail,
guess the incline uphill, downhill, camber. flat ground bounce? when it starts, does it puff black smoke? when it dies, does it sputter first, or just die?

 

[BCGPER]

You want to just run it down? I've been through this major PITA, we can get it easily fixed. Unless I can see it, I'll send you on 100 goose chases.

As you know I know little about Jeeps...It has a elecric fuel pump on it already and possibly a manual theres what appears to be a manual pump on the front driverside on the engine

What do you suggest to use to insulate the fuel lines?

exhaust is single running between the dtrain and the frame rail on the ds with the fuel line running outside the frame rail on the ds

 

[Shawn]

Don't over look the possibility that your fuel pump might be going out.

 

[ALF]

which carb is it, does it do it when it's going uphill or downhill on the flat? it could be as simple as an improperly set float level. Give us some more detail,
guess the incline uphill, downhill, camber. flat ground bounce? when it starts, does it puff black smoke? when it dies, does it sputter first, or just die?

it does it at all inclines and flat surfaces...sputters first...no black smoke on start up

 

[PSD_FTW]

Everyone is always worried about the exhaust but yes - Fuel line touching the coolant system will do it too. I had a 78 bronco with the fuel line that was bent enough to touch the lower radiator hose and it would Vapor lock like a champ =) Bent the Fuel line a bit and it never did it again.

 

[ALF]

Everyone is always worried about the exhaust but yes - Fuel line touching the coolant system will do it too. I had a 78 bronco with the fuel line that was bent enough to touch the lower radiator hose and it would Vapor lock like a champ =) Bent the Fuel line a bit and it never did it again.

thats what I did hopefully it works

 

[rockreligious]

Fixed? what was it?

 

[ALF]

UPDATE:greg:

generally this problem was minimal during colder weather, now that its hotter it got much worse. At the very beginning of rattlesnake yesterday it died completly

The tools came out and after 10 minutes of trouble shooting and some swapping of parts around the problem was solved

For a reason unknown to me a mechanical and electric fuel pump were installed inline, the electric fuel pump failed (I'm guessing at higher temps) so it was bypassed and now all is good!