Is my fuel pump going bad?

[venom]

After having to mothball my project for the holidays, I went out to start it, just to keep the fluids moving. When I cranked it over, I found that the pump wasn't picking up fuel. It wasn't like I only cranked it for a second or two, but quite a few seconds. I ended up putting fuel into the carb to get it to kick over, and at that point it seemed to pick up fuel and run as expected.

Is that indicative of a fuel pump going bad?

Now, to add to the mystery, I have an in-line fuel filter in place. I put it in years ago for some long forgotten reason, but I have noticed that the fuel will drain back to the tank. I'm not sure if that's common and expected or not.

After the new year I'll be picking back up where I've left off, and if I should replace the pump, I'll get it done. I there's something else I should be looking at, please point me in the right direction. I can say that the fuel lines all look good and there are no apparent leaks, so I don't think that's the cause.

Thanks, guys!

 

[Torxhead]

First guess would be cracks in the plastic fuel line right out of the gas tank. This is usually one of those items that gets put off due to its a pita to get at. I like having an inline fuel filter just before the pump.

 

[venom]

Thanks! I'll take a look and see if that's the problem. I'll look into moving the in-line filter when I'm working on it. Right now it sits just after the pump.

 

[Lumpy Grits]

How much fuel was in the tank?
X2 on checking all fuel line connections.
When I have let my jeep sit for a couple of months. It will take 5-10 seconds of cranking to fill the carb bowel and to fire off.
If I drive mine everyday-It starts right up.
LG

 

[venom]

How much fuel was in the tank?
X2 on checking all fuel line connections.
When I have let my jeep sit for a couple of months. It will take 5-10 seconds of cranking to fill the carb bowel and to fire off.
If I drive mine everyday-It starts right up.
LG

That's what I had experienced before this most recent issue, the starting every day or 5-10 seconds after having not started for a few days. This was the first time it didn't pickup the fuel pretty quickly.

I've got very little fuel in it, probably around 1/8th tank or less.

 

[Torxhead]

On the BBD carb, that came with the later CJs, there is a fuel bowl vent valve that could be the problem. If it sticks in the open position, fuel in the bowl will evaporate. As I recall, it was located on the top air horn. I would think a BBD guru like Lumpy would be familiar with this. It is operated by the evap system vacuum motor on the oem air cleaner looking at the fsm on page B-316.

 

[Hedgehog]

As you grow and learn opinions can change. I was absolutely death on electric fuel pumps, didn't like'em no way. I didn't like being dependent on a system that seemed fragile somehow, a system that could easily leave someone stranded in the back country. That thought has changed with lately. A vehicle I just bought had an electric fuel pump already installed, it was installed all wrong, but it was there non the less. The pump is small and will allow flow to the engine, but has a very solid back flow preventer. It is perfect for both a priming pump AND a back up. The vehicle it was on has many fuel related problems. The fuel tank needed cleaning, the fuel line was an absolute backdoor mechanic MESS and it was said that the fuel pump was bad. The tank is cleaned, the fuel pump replaced, new fuel line from the pump to the rebuilt carb. However the fuel line from the tank is still unfinished, but the engine was ready to be awakened from it's 25 year sleep. The electric fuel pump was added and a line was placed in a gas can. with the engine and fuel pump hot wired you could hear the float bowl fill. The sleeping engine fired right up. I disconnected the electric fuel pump and she ran like a champ. Since I am absolutely sold on having one of these little E-fuel pumps and the decision has been made to keep the electric fuel pump as a priming pump, a back up and a backflow preventer.

 

[venom]

On the BBD carb, that came with the later CJs, there is a fuel bowl vent valve that could be the problem. If it sticks in the open position, fuel in the bowl will evaporate. As I recall, it was located on the top air horn. I would think a BBD guru like Lumpy would be familiar with this. It is operated by the evap system vacuum motor on the oem air cleaner looking at the fsm on page B-316.

I have to wonder if I had that problem with my original Carter. I'm running a weber. It's pretty new. I can say, without a doubt, that the fuel will be okay for a day or two, but any extended period (a week or more) and it takes a good bit of cranking. This last time, though, was simply different.

As you grow and learn opinions can change. I was absolutely death on electric fuel pumps, didn't like'em no way. I didn't like being dependent on a system that seemed fragile somehow, a system that could easily leave someone stranded in the back country. That thought has changed with lately. A vehicle I just bought had an electric fuel pump already installed, it was installed all wrong, but it was there non the less. The pump is small and will allow flow to the engine, but has a very solid back flow preventer. It is perfect for both a priming pump AND a back up. The vehicle it was on has many fuel related problems. The fuel tank needed cleaning, the fuel line was an absolute backdoor mechanic MESS and it was said that the fuel pump was bad. The tank is cleaned, the fuel pump replaced, new fuel line from the pump to the rebuilt carb. However the fuel line from the tank is still unfinished, but the engine was ready to be awakened from it's 25 year sleep. The electric fuel pump was added and a line was placed in a gas can. with the engine and fuel pump hot wired you could hear the float bowl fill. The sleeping engine fired right up. I disconnected the electric fuel pump and she ran like a champ. Since I am absolutely sold on having one of these little E-fuel pumps and the decision has been made to keep the electric fuel pump as a priming pump, a back up and a backflow preventer.

So, you're going to leave the pump in place and have it prime through the mechanical pump when necessary?

I had thought of going to an e pump years ago, but my desire to not be reliant upon a "failure prone" device steered me away from it. I had never thought of running both, but it sounds like a good idea, and falls into that 2 is 1 and 1 is none school of thought.

 

[Hedgehog]

Long post, I got tangled in the words ..... Yes, I am going to run both. Didn't really know it was possible to push fuel through a mechanical pump. Now I know.

Not all E-pumps will allow fuel to freely pass thru. So, if you are thinking about doing this, make sure the pump will allow fuel to pass and has a back flow check valve. This feels like the best of both worlds, there might be something wrong with my logic.

 

[Lumpy Grits]

That's what I had experienced before this most recent issue, the starting every day or 5-10 seconds after having not started for a few days. This was the first time it didn't pickup the fuel pretty quickly.

I've got very little fuel in it, probably around 1/8th tank or less.

Then fill the tank.
LG

 

[Hedgehog]

So you are saying that for all practical purposes the tank is empty........ Glad that's cleared up......... In about 200 miles you might experience this problem again...

 

[Scorzany]

My fuel gauge does not read right. Mine reads empty when I got 1/2 a tank left. Surprise huh? Yeah, yours might be off too.

 

[mdeluca]

As you grow and learn opinions can change. I was absolutely death on electric fuel pumps, didn't like'em no way. I didn't like being dependent on a system that seemed fragile somehow, a system that could easily leave someone stranded in the back country. That thought has changed with lately. A vehicle I just bought had an electric fuel pump already installed, it was installed all wrong, but it was there non the less. The pump is small and will allow flow to the engine, but has a very solid back flow preventer. It is perfect for both a priming pump AND a back up. The vehicle it was on has many fuel related problems. The fuel tank needed cleaning, the fuel line was an absolute backdoor mechanic MESS and it was said that the fuel pump was bad. The tank is cleaned, the fuel pump replaced, new fuel line from the pump to the rebuilt carb. However the fuel line from the tank is still unfinished, but the engine was ready to be awakened from it's 25 year sleep. The electric fuel pump was added and a line was placed in a gas can. with the engine and fuel pump hot wired you could hear the float bowl fill. The sleeping engine fired right up. I disconnected the electric fuel pump and she ran like a champ. Since I am absolutely sold on having one of these little E-fuel pumps and the decision has been made to keep the electric fuel pump as a priming pump, a back up and a backflow preventer.

Would love a step by step on how best to do this.
Which electric pump did you use or recommend?
I'm convinced that my weber loses its fuel.
Can you have both manual and electric pump?

 

[Hedgehog]

First I have very Limited experience with Electric Fuel pumps. With that being said over the years using a priming pump has been discussed both here and other places. At first I thought they were running some complicated duel or "Y" type fuel line that isolated one pump from the other. Then a tread popped up that mentioned "Pass through" pumps where fuel could easily pass through an Electric fuel pump and fuel could be pumped through a stock mechanical pump. When my newest (old) vehicle came to me it had a small low pressure inline E-pump very poorly installed. So, I pulled the pump and noticed that air, I.E. I blew air through it, would pass through it in one direction with no restriction and not pass in the other direction. Hmmmmmmm! Obviously a check valve or backflow preventer. So, when I needed to start the engine without a fuel line or gas tank installed the chance to experiment with the E-pump and stock fuel pump presented itself.

With the E-pump pumping fuel from a gas can I heard the float bowl fill and stop properly. With the engine running properly I disconnected the power to the E-pump. The engine didn't stumble at all. This was a very short experiment, but everything worked as expected.

I'm not sure which pump it is, there is no real name on the pump, I tried the serial number and drew a blank, but there are several similar, inexpensive pumps available.

 

[sparkzaflyin]

Personally, I would be hesitant to install any kind of electric fuel pump ahead of a mechanical pump do to safety concerns. Maybe with rollover shut off valve.

 

[Hedgehog]

I plan to run mine on a manual switch along with an automatic cut off switch available similar to those used in fuel injected vehicles from the factory. These switches are highly recommended when using E-fuel pumps, it doesn't really matter if there is a mechanical pump in line or not.

 

[Lumpy Grits]

External mount, electric fuel pumps are 'pushers' and not 'suckers', like engine mounted mechanical fuel pumps are.
Best to have the electric f'pump as close to the fuel tank as possible.
X2 on an emergency shut off for the ele. pump.

LG

 

[Hedgehog]

Lumpy - You are nothing if you are not consistent. All the time I was fooling with the E-pump the words, "Pushers not pullers." was going through my head.

 

[mdeluca]

Excellent... thanks guys...!

When I get closer I'll do more research on best manufacturers for pumps and switches.