help 81 cj7 2.5. sputtered and died

[jesseb]

Hi, My CJ7 just left me stranded in the middle of the road. I was able to get it off the road by turning it over and driving it on the starter. Anyways the jeep runs well and starts every time but on cold days it will occasionally sputter a little and loose all power but pumping the gas with the clutch in it seems to pass and then runs strong again. I always chaulked this up to a little moisture in the tank and didn't think much of it. Tonight it does the same thing but totally stalls and when I try to start it it sounds ruff and won't go. Any ideas? As always thanks for any info.

 

[Saddle Tramp]

What about the fuel pump? Fuel pumps (mechanical) when starting to fail will work some times and not others. I’ve had them leave me stranded on the side of the road; sat 20 minutes then off you go. Also they will sputter as you say then work fine until they eventually just stop working all together. The other option could be a break (or bad connection) in the fuel line that is allowing air into the system. Short of that the next stop is the fuel filter then on to the carb. I’m not a carb expert as far as the internals go but before you crack open the rebuild box I would check for air leaks around the base of carb and any vacuum hose problems. If you think the pump is OK then start at the carb looking for vacuum and air leaks and work back.

 

[jesseb]

I will check the fuel pump but a friend recomended just checking the fuel filter. I am a little embarrassed but I can't seem to find the fuel filter. I know it should be on the side of the carb I just don't see could someone post a pic of the fuel filter. Thanks

 

[Saddle Tramp]

I will check the fuel pump but a friend recomended just checking the fuel filter. I am a little embarrassed but I can't seem to find the fuel filter. I know it should be on the side of the carb I just don't see could someone post a pic of the fuel filter. Thanks

Maybe you don’t have a fuel filter. The filter should be in line between the fuel pump (mechanical) at the side of the engine block and the carb inlet. I believe in 1981 there still should have been a return line to the tank so the filter would have one inlet and two outlets.

 

[jesseb]

So finally had some warm weather did a new fuel pump, filter, plug wires ignition box and plug wires. Cap and rotor looked good and so did the plugs. It seemed to be good then 10 minutes into driving it the same thing happened. Second gear accelerating from a rolling stop it just died. any ideas it seems to get spark and fuel I just don't know where to look next. After it dies it won't start till it cools for about an hour. The motor is not running hot its at about 3/8th engine heat on the factory temp gage.
Thanks

 

[Torxhead]

Fuel delivery might still be your problem. Possibly a pin hole leak between the rubber fuel line from the gas tank and the hard line to the fuel pump. This would be quite possible if it is still the oem fuel line. There are a few other possibilites and a fuel pressure check would help here. It should be around 4-5 p.s.i.

 

[grozam]

I have a plastic boat gas tank that I use to run my cars and trucks that eliminates any problems from the pump to motor. if you can hook something like that to the pump and it runs ok then the problem would be behind the fuel pump.

 

[jesseb]

If there was a pin hole would I see the gas residue somewhere? I am just about ready to take it to a mechanic. Any ideas on why this would happen once its warm and under mild strain then won't start for an hour? Looks like some some storms coming my way so I won't have a chance to crawl under it for a week or 2.
Thanks

 

[Torxhead]

You should determine if it is a fuel or spark problem. A pinhole leak in the location that I mentioned, would be hard to spot. You did say that you replaced the fuel filter, did you locate it or install one? As sometimes they are located inside the carb, I am not sure of the oem location here. Another possibility would be a clog prior to the fuel pump, like the fuel pickup sock in the fuel tank which is hard to get at. That issue should be determined by checking for a siphon flow prior to the fuel pump.

 

[grozam]

I have a plastic boat gas tank that I use to run my cars and trucks that eliminates any problems from the pump to motor. if you can hook something like that to the pump and it runs ok then the problem would be behind the fuel pump.

If you do this ,and still have the problem, you can eliminate the pick-up sock and the fuel line from the problem

 

[jesseb]

I changed the stock fuel filter it was located in the carb. I also put a new fuel pump in and the hook ups seemed fin. I tried a shot of starter fluid right after it stalled and that did not get it to start. It is my understanding that if its fuel then a shot of starter fluid should get it going again or at least get it to start off the starter fluid? I'll check the line again but I am thinking its spark but not sure were to look next the problem is its not a consistent failure so when I look at it everything seems to work great then it stalls on me in a less than ideal place and its hard to work on.

 

[CJB4POWERBILL]

Go buy u a 1 in 1 out clear fuel filter to replace your factory 1 in 2 out. When it dies get out and see if filter is dry. If so you have delivery problem. Then check your lines from tank to pump, and if ok there your pickup inside tank has problems mabey. Replace it next. My B-law cj did same thing and he replaced sending unit and didn't solve either. After he capped off tank vent and went to gas cap with breather it never did it again ? Vapor lock mabey Idk.

 

[CJB4POWERBILL]

And if u think spark issue, with your new dist and Ign module u may have a cut wire. Take u a length of Orange and purple wires to reach from IM to dist. Splice Orange to Orange and purple to purple at each end. U just bypassed factory harness that hooks IM to dist and any chance of short in the loom. AKA NUTTER IGNITION.

 

[CJB4POWERBILL]

you should have Purple and Orange coming out of plug at distributor and purple and Orange coming out of plug at bottom of IM...that's Wat u need to hook to each other.

 

[Torxhead]

Jesseb, since the starter fluid didn't work, it probably would be an intermittent ignition problem. With that it could be the ignition control module, these would be warm to the touch after it stalls out or you could have it checked at an auto parts store after removing it. It should be located under the coolant bottle on the left front fender well.

 

[mtnwhlr]

sounds like you Ignition Module is getting hot and stops working then when it cools off it works again.

 

[jesseb]

Thanks I'll check that next. Hopefully I will have a warm evening in the next week.

 

[CJB4POWERBILL]

Did you not say on post #5 u just replaced the ignition box ?

 

[Torxhead]

Did you not say on post #5 u just replaced the ignition box ?

Good catch, Powerbill, a cheap ignition control module can be bad right out of the box though. Another possibility would be a bad coil, which can be checked with a multimeter.