The CJ is slowly running worse and worse...

Over the past 2 weeks the CJ has started going downhill...

First it just had trouble starting, it would crank and crank until if finally fired. Then it would start to fire, stumble for a bit then finally catch. Now when it starts as often as not it backfires like a gunshot (it lit up the street last night).

It's started idling rougher and rougher, I've given it a quarter turn more gas on the idle adjustment screw to see if it had just rattled itself too low, no dice. Every now and then it will just die at idle which it never used to do. I had to start it in traffic while rolling yesterday because I took my foot of the gas and put in the clutch as I made a turn.

Sometimes now if I give it gas going on a light uphill to speed up on it the engine will stumble a few times before it catches.

I'm kind of at wits end on what I should do with it. This is my only car right now after my XJ was totaled so I need it to work. I've biked for a while and that's not too bad but it's getting over 90 every day now and I don't want to arrive everywhere all sweaty.

Does anybody have any recommendations on what to check?

 

How hard is it to rebuild a carb? Are we talking a few hours on the weekend? I've never done it before.

 

I think I'm going to try the fuel filter first, it's the one from the PO and I know he didn't replace it. Who knows how old it is...

It looks like its a $4 part over at the FLAPS. It should be done sooner or later anyways.

 

I'm not sure. It's a '71 but it appears that the tank has been modified. Did the '71 have the rear tank or the under seat tank? Mine looks like somebody punched a hole in the back of the rear quarter panel themselves and stuck in a tank under the rear of the vehicle. The hole isn't that smooth.

 

Might want to clean out the tank while you're at it, if it's not too hard to take out. Might have rust, water or other crud in it.

 

Might want to check distributor cap and rotor also. Can cause similar symptoms. Nickmil

 

Is it as simple as just pulling it and checking for charring or dirty contacts? Never did that before, it sounds easy enough but I prefer to get it right the first time.

 

Pretty much. If you remove the ignition wires from the cap make sure you mark them so you know which position they go back in. Check for charred/worn looking contacts. Also with a small light check for very small lines in the cap between the posts. They sometimes look like cracks. This is called carbon tracking and can cause crossfiring between cylinders. Definitely replace the fuel filter, sounds like time anyway. If you still have points check and see if the contacts are worn/burnt. This will also cause your symptoms and will get progressively worse as the engine is run. not saying these are your problems, but things to look at. Keep at it. With help from this board you should be able to figure it out. Nickmil

 

Don't want to sound negative or anything but that sounds a lot like my jeep as of a few months ago. It finally got to the point that it would not idle at all. It really made filling up at the gas station a challenge since at the time i wouldn't trust it to shut off and restart. I ended up doing an engine rebuild after working on every possible thing.

Besides that, The comments above are good ones, but I will through another one out there that gave me a hard time. Check your automatic choke. I assume you also have the Rochester 2 barrel like I do. I noticed that it would slip around with time and not control airflow like it should. This could also explain why it is getting worse with time... Outside temperature is rising and the engine might not need to be choked as much, although I had to manually force my choke closed to start it even on the really warm days to start before the engine was rebuilt.

 

Condensors go bad too, that's the little cylinder-looking thing in the distributor.

 

Hopefully not... and that would mean it went downhill FAST. It was running like a champ 2 weeks ago. I'll check the distributor this evening and try the fuel filter also. From the outside at least the distributor looks brand new. All the ignition wires and the distributor were replaced in November.

 

did you buy gas @ a different location than normal,or buy gas while the tanker was dropping? if so on either you may have water in fuel,and its a real pita,when you go to change the filter catch some gas maybe even hook up a line from the carb side of the fuel pump to a container and run it for a few minutes examine the fuel water is easy to see,it will settel to the bottom

 

:iagree:

 

Check that the wires going onto the cap and the coil are not corroded, that will make a bad connection and cause running problems.

 

Ya know, I'd forgot about this....my dad bought gas for their Caddy once while a tanker was filling the underground tanks, and on their way to OKC the Caddy just died. He had to have the fuel filter replaced, but he kept the old one and when he got home he sawed it open. It was completely full of this green, waxy goo. Something that either was in the truck with the new gas, or something that was stirred up in the underground tank.

 

I just thought of something... Phoenix switches to a higher ethanol mix over the summer to combat smog. With an ethanol mix of 10% will that cause any symptoms like this? I've got a buddy who has a '69 mustang that won't idle worth a darn and it just started a few weeks ago.

 

Hard starting could be the fuel system, but backfiring sounds more like timing. I am no expert, but these are the two things I would check first. And sometimes just a good cleaning will help your carburetor
Doug/Tucson