CJ-5 starts but immediately dies

[peterplaysbass]

Hi everyone - I'm new here, so if this is posted in the wrong place or is a redundant question that is answered by another thread, please let me know.

I've got a '79 CJ5 with the AMC AMC 258 i6 / 4.2l liter in it (3 speed manual) and if I fill the bowls in the carb with fuel, it starts right up, but dies shortly after. I'm wondering what the smartest way to trouble shoot the problem is. What's the first thing to check? I'm looking for quick/easy fixes. I don't want to rebuild the carb only to find out all I needed was a hose replacement, you know?

One possible additional clue is that the battery seems to get a little too low too quickly when I'm attempting several starts. It cranks strong for the first 5-8 attempts or so, then makes a loud buzzing noise when the key is turned to the 'start' position. There's no slowing of crank to warn me that the battery is low. I cleaned the terminals and connections well and charged the battery, and I still get similar results. Could a poor electrical connection be causing my issue? Is it likely that I have two separate issues?

Thanks in advance for all of your expertise!

 

[JimsCJ5]

Try it with a known good battery to at least rule out the option you have a bad battery. Then, once spark is confirmed, go to the carb and make sure you are getting fuel.

 

[peterplaysbass]

I'll give that a try - thank you. I'll let you know what happens.

 

[peterplaysbass]

I tried it again with a good battery - same results. Twice I got it to fire by putting a little fuel in the carb, but it dies after a second or two.

I tried the throttle under the hood while looking down the carb, and sure enough - no fuel. I should see fuel spurting out of the jets when I move the throttle, right? What's the recommended trouble shooting order here?

EDIT: this may be relevant - there's no fuel filter anywhere, although there's two in a cardboard box that came with the Jeep. I'm guessing the PO took the old one out and never put the new one in. Embarrassingly, I'm not sure where to splice it in. I've changed them before, but I never had to think about where the new one went - I always just put if where the old one was! (end EDIT)

Thanks, everyone!

 

[JimsCJ5]

It should be right in front of the carb.
crank the engine with the fuel line disconnected (in a fuel safe container) and see if the fuel pump is working. If so, your problem is in the carb.

 

[peterplaysbass]

OK, I will try that now and let you know how it goes. Thanks again!

 

[peterplaysbass]

I pulled the fuel line heading into the carb off and stuck it in a bowl, cranked for 20 seconds, and got nothing. I'm going to assume it's the pump at this time. I ordered one ($18) and I've replaced mechanical fuel pumps before, so I'll assume this is the problem and see if the fix works before I try other more difficult things.

Thank you!

 

[mriplaybass]

Did you check to see if there was fuel in the line going to the fuel pump? You should have a return style filter on this engine. The filter should be located near the carburetor. It is important that the filter is oriented so that the smaller line (return) be located directly above the larger one (supply). The single connection side of the filter is obviously from the fuel tank. It is common for these Jeeps to loose prime if they sit for a while, but usually a little gas down the carb throat is all that is needed. Sounds like you have an obstruction in the supply line, or a bad pump.

By the way, love the name! (BOOM BA BOOM BOOM BOOM)

 

[Lumpy Grits]

Put 5 gal of FRESH gas in the tank-Don't trust the gauge.
Don't buy Crown/Omix stuff as it's China JUNK.
Replace the fuel filter, and make sure the filters return line is at the 12 o'clock position.
Here's a picture of the fuel filter. It's just below the #6. It's the steel can on the fuel feed line to the carb.
AMC 258CID I6
You really need to get a copy of the FSM. Here's a PDF......
http://oljeep.com/gw/79_tsm/79_Jeep_TSM.pdf
As far as your battery goes. How old is it? What's the CCA?


LG