Not getting fuel to carb....

[Rust Bucket]

Ok, this thread is going to require some history to diagnose. Many of you will remember, I replaced the gas tank a few months ago with a rusted out used tank. Rust entered the fuel line and clogged the carb, so I replaced the tank and filter (several times), then rebuilt the carb. It ran for a few weeks, but now it's not getting fuel. I tested the line coming out of the fuel pump, but not a drop is coming out. I have about 3/4 of a tank of gas and am stumped.

Is there a way to test the fuel pump?

Does anyone have another suggestion?

Steve

 

[Petescj]

Im gonna guess there was some residual rust in the lines and it clogged your fuel filter after a while. Did you try a new one already?

 

[Rust Bucket]

Im gonna guess there was some residual rust in the lines and it clogged your fuel filter after a while. Did you try a new one already?

I took the filter off and tested the line coming out of the pump. It didn't even have a filter until I installed it after the carb rebuild. So, to answer your question, yes, the filter has been replaced and is currently off.

Thanks for the response Pete!

When the pump dies, does it just stop working or does it slowly create less pressure?

 

[Petescj]

Your fuel pump is the mechanically driven stock unit I presume? If you would run a line into a can or bottle and turn the key over it should pump fuel into the container. I never had one go bad myself so Im not sure on the fading pressure or just dying part. If it is the pump itself its relatively easy and pretty cheap. The one listed is for a AMC 258 i6 / 4.2l .

Fuel Pump and Other Jeep Parts and Jeep Accessories by 4 Wheel Drive Hardware

 

[Rust Bucket]

Your fuel pump is the mechanically driven stock unit I presume? If you would run a line into a can or bottle and turn the key over it should pump fuel into the container. I never had one go bad myself so Im not sure on the fading pressure or just dying part. If it is the pump itself its relatively easy and pretty cheap. The one listed is for a AMC 258 i6 / 4.2l .

Fuel Pump and Other Jeep Parts and Jeep Accessories by 4 Wheel Drive Hardware

I tested the pump by putting the fuel line from the pump into a glass jar and turning the engine for about 20 seconds, 3 separate times. It didn't collect a drop....

 

[Old Dog]

Even a bad (stock) fuel pump should spit out a little gas. If there is nothing comming out I think you have a cloged line somewhere.

 

[Rust Bucket]

Even a bad (stock) fuel pump should spit out a little gas. If there is nothing comming out I think you have a cloged line somewhere.

I really hope that's not the case. Replacing a fuel line is not something I desire to do right now......

I read another post on a different site and some guy had the same problem as me. He let the Jeep site for 4 weeks during winter and the pump died. Apparently, the "diaphram" broke and he simply replaced the pump. It started right up after the replacement. Has anyone else ever heard of this?

 

[dalefan88]

your pump might be bad. i run a clear inline filter before the pump and the stock one after the pump. the clear one lets me know whats going on by watching it .

 

[coldwater]

Well, I'll say this. A new pump is pretty cheap, so why not just take a few minutes and replace it. I had one go bad once, and It actually started to drop fuel into the oil pan little at a time through a damaged diapragm. You could smell the fuel at the dipstick.

 

[IOPort51]

Remove the fuel line that goes into the pump. Remove the fuel line at the tank. apply compressed air to line to check for resistance (blow in it).
If you put your finger over the inlet side of the pump you will feel the suction when it is turned over.
The only times I have ever seen a pump fail it put fuel in the oil pan, but it still pumped to the carb.

 

[Rust Bucket]

your pump might be bad. i run a clear inline filter before the pump and the stock one after the pump. the clear one lets me know whats going on by watching it .

That's a good idea. I only run one filter now, but the clear one would surely make it easier to see the fuel flowing.

Well, I'll say this. A new pump is pretty cheap, so why not just take a few minutes and replace it. I had one go bad once, and It actually started to drop fuel into the oil pan little at a time through a damaged diapragm. You could smell the fuel at the dipstick.

I saw the new fuel pumps online for about 50 bucks, so I'll just replace it anyway. Hell, if nothing else I have ANOTHER new part that never needed to be replaced, lol.

Remove the fuel line that goes into the pump. Remove the fuel line at the tank. apply compressed air to line to check for resistance (blow in it).
If you put your finger over the inlet side of the pump you will feel the suction when it is turned over.
The only times I have ever seen a pump fail it put fuel in the oil pan, but it still pumped to the carb.

I like this idea, but hate knowing that I must drop my fuel tank a 5th time to get to the fuel lines. But, you make a good point. I would know if the line was clogged.

Thanks for all of the replies. Any other ideas are welcome!!!

 

[mikes toy]

Had the same problem on my 76 CJ7 AMC 304 . Replaced fuel pump.Cranks every

time now

 

[IOPort51]

see if the pump draws first.
I would say blow in the fuel line with out disconnecting the tank but if it is full of it would be best if it did not get forced into the pick up tube filter

That's a good idea. I only run one filter now, but the clear one would surely make it easier to see the fuel flowing.



I saw the new fuel pumps online for about 50 bucks, so I'll just replace it anyway. Hell, if nothing else I have ANOTHER new part that never needed to be replaced, lol.



I like this idea, but hate knowing that I must drop my fuel tank a 5th time to get to the fuel lines. But, you make a good point. I would know if the line was clogged.

Thanks for all of the replies. Any other ideas are welcome!!!

 

[Rust Bucket]

Had the same problem on my 76 CJ7 AMC 304 . Replaced fuel pump.Cranks every

time now

+

Good stuff. Was it hard to replace? I've heard some people say it's a joke and others say it requires two people. Of course, I've never asked a CJ owner directly.

see if the pump draws first.
I would say blow in the fuel line with out disconnecting the tank but if it is full of it would be best if it did not get forced into the pick up tube filter

I'll try your idea out of curiosity, but probably will just replace it anyway. It's only 50 bucks!

Funny thing is, I keep saying that same line, It's only 50 bucks. I'd hate to add up all of those 50 dollar parts for a grand total!!! Oh well, what else would I be doing while drinking, lol.

 

[Petescj]

Its relatively easy. You wont need another person.

Good stuff. Was it hard to replace? I've heard some people say it's a joke and others say it requires two people. Of course, I've never asked a CJ owner directly.

 

[Rust Bucket]

Its relatively easy. You wont need another person.

Good, thanks!

 

[crscrkcj]

Your fuel pump bay be internally clogged. I have seen this before on older vehicles. If the pump can be disassembled, take it apart and clean it out. Some of the inlet valves may be blocked. Rebuild kits for these old fuel pumps should be cheap and easy to install if available.

 

[kicknjeep]

hey Pete he has an AMC 304 V8 a little harder to replace(fuel pump) but deff doable. I am with port51 and believe if there is/was rust in the tank may be some in the fuel line as well. But if it is an old FP then by all means cheap enough to go ahead and replace.