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Unread 10-16-2002, 08:53 PM   #1
russ240
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cj7 cutting off, help!

Alright my dad bought a cj7 a while ago, it's a 78, i love riding around in it. There's a problem with it though. It takes a time or 2 with giving it gas to start, that's not a real worry to me, the problem is that after riding in it for about 15 minutes(pretty much when the engine warms up) it starts cutting off on me. To keep it going you have to be giving it gas all of the time, which means if you don't shift fast enough it cuts off, and when i took it to ride in the mud today it was a real pain. My dad said it might be something like vaccum lines or something. Anybody have any help for me? Thanks a ton.

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Unread 10-16-2002, 09:02 PM   #2
jadams68
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Replace your fuel filter first. If it's clogged up, this will cause you to stall like you've explained.

Let us know.
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Unread 10-16-2002, 09:07 PM   #3
russ240
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it was replaced along with spark plugs and spark plug wires about 6 months ago, also a new alternator and starter were put in about a year ago
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Unread 10-16-2002, 09:24 PM   #4
jadams68
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Ok, that's good to know up front. Also, what engine are we talking about?

Did it ever run fine? What changed last? Did you do any work on the engine recently that may have caused an issue with the Timing, the carb idle mixture, choke settings, etc?

Do you have gas that was sitting in it for months?

How about the fuel pump?
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Unread 10-16-2002, 09:31 PM   #5
russ240
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Quote:
Originally posted by jadams68
Ok, that's good to know up front. Also, what engine are we talking about?

Did it ever run fine? What changed last? Did you do any work on the engine recently that may have caused an issue with the Timing, the carb idle mixture, choke settings, etc?

Do you have gas that was sitting in it for months?

How about the fuel pump?
Alright hang in here with me, i don't know much about jeeps. I'm guessin it's the stock engine, it's a straight 6, that's all i know. It did run fine for a while, we bought it about 2 years ago, worked find for about a a year or so, started acting up and such, so my dad took it and got a tune up done on it about 7 or 8 months ago. It worked fine for about 2 months after that, and ever since then we haven't driven it much because it is always cuttin off. The gas in there now hasn't been in there for more than a month, and i'm not really sure about the fuel pump. If you can tell me where and what it looks like, maybe i can look at it and see if it looks like crap or whatever you tell me. Thanks a lot for the help.
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Unread 10-16-2002, 09:31 PM   #6
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one more thing when the tune up was done and they replaced the spark plugs the dude showed me the spark plugs and they were pretty black with crust stuff on them if that helps, thanks.
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Unread 10-17-2002, 12:31 AM   #7
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It sounds like a vacuum leak or the carb is bad. Runs fine when cold because its running rich from the choke. After the choke is off, it's diing because it's way too lean. Check any vacuum line that runs to the intake manifold or carb for holes or leaks. If they are okay, get a new or rebuilt carb.

Plugs all black? Flat black or cruddy black with a build up of goo? Flat black was running rich. Build up of oil or goo is probably caused by weak compression in that cylinder.

If you don't know what or where any of these parts are, you need a Chiltons or Haynes manual. The Jeep service manual is the best but expensive. You really can't repair something that needs troubleshooting if you don't have mechanic experience. It's tough even for a good mechanic to pin point some problems with rough running engines. Like mine, it runs rough only after being on the hiway for a few minutes and then slowing to city speeds. It goes away after 5 or so minutes of city driving. I've been trying to figure this out for a month now and I'm a pretty fair wrench. Hope this helps.
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Unread 10-17-2002, 06:32 AM   #8
jadams68
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Does it idle rough or does the idle surge up and down?
Let's go with the easy part first.
Listen for a vacuum leak. Go around the engine compartment while the jeep is running (keep fingers away from fan).

Listen for hissing noises...look at all the hoses coming from the top of the valve cover to the carb, all the carb vacuum lines and the lines going to the charcoal canister (that coffee can down on the bottom right of your engine near where your left foot would be.

Let's rule that out first....
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Unread 10-20-2002, 03:27 PM   #9
russ240
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alright i went outside to check some of the stuff yall said to, for leaks and all. Tried to start the jeep up, now it won't stay on, i crank it and the engine comes on but with a very rough idle and you have to give it gas for it to stay on, also after i tried to start it up i looked at the engine and the carb had smoke coming from it. bad carb or what? Also what would a good, and also cheap place be to find a replacement(website?). Thanks.
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Unread 10-20-2002, 04:38 PM   #10
Tuts
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My grandfather's old dodge pickup had the same type of problem and it was due to the spark plugs being crudded up with crudd. Or some cruddy thing like crudd. When the truck cut my grandfather said, "Crudd." I still don't know if he meant crudd as in damn or crud as in there is crudd in the spark plugs. He really knows his stuff and in his day could fix any motor problem conceviable. Sort of a mechanical genious.
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