Fuel Not Flowing!-Update-Still Not Working

[stingus]

So I picked up my Bronco today from my mechanic, new electric fuel pump, new fuel lines. The new fuel pump is mounted on the frame towards the front of the engine. My mechanic also dropped the tank and said the filter was not clogged. Drove great for about 45 minutes, then all of the sudden it bogged down till I had no power again and barely coasted off the side of the road. Turn the key and i hear the pump running so I'm assuming its pumping ok. Waited 5 minutes, cranked it up, got to the Auto parts store. Looked at the fuel filter I installed 2 weeks ago, and it had lots of debris inside. Replaced the filter and it ran pretty good for the 20 minutes it took to get home. Got it home safely.

Left it running, looked under the hood, revved it up, had a good constant fuel level in the filter. I don't think it is an ignition problem b/c it is bogging down and not just cutting off. Do i need a new fuel tank? Would the debris in the filter be enough to cause the engine to bog down all of a sudden while going 60 mph? The fuel lines are running against the frame and don't seem to be too close to the manifold so I wouldn't think the lines are getting too hot.

More help and suggestions would really be appreciated.

Thanks!

Ben

 

[Master Chief]

OK, from your earlier thread until now it sounds like the fuel system is good. How old is your carb? Have you replaced it lately?

If it is old, I would take it off and pull it apart on a bench for a good rebuild and cleaning...this is a fairly inexpensive process and quite easy to do.

If it is new, what brand is it and are the floats properly adjusted?

 

[stingus]

Its an Edelbrock 4Barrel. I don't know how new it is though. Looks clean but who knows. I asked my mechanic if it was adjusted properly and he said it was. how do you tell if the floats are adjusted right?

 

[Master Chief]

Fing your part number, it's located on the front left and then read this instruction manual: http://www.edelbrock.com/automotive_new/mc/carbs_acc/pdf/carb_owners_manual.pdf

It really sounds to me like you either have dirt in the bowls or the floats are not set right. The nice thing with the Edelbrock carb is almost everything can be done without removing it from the engine.

 

[Master Chief]

Another thing to look at is your coil. I think you said your mechanic replaced the plugs/points/cap ect. but your coil may be the problem. They can breakdown when they get hot causing your stumbling/cut out problems.

 

[Viperwolf1]

If there's debris in the fuel system then it has probably made it's way into the float needle/seat assembly. The bogging could be the carb flooding because the needle can't close completely. Does it puff out black smoke when it happens?

 

[stingus]

Another thing to look at is your coil. I think you said your mechanic replaced the plugs/points/cap ect. but your coil may be the problem. They can breakdown when they get hot causing your stumbling/cut out problems.

I did the plugs/wires. I think the coil should be fairly inexpensive and I believe i could change it out. Sounds like a good project for tomorrow. Thanks also for the carb link and info!

 

[Master Chief]

Before I put on a new coil I would pull the top of the carb off to see what's up in there. Don't be afraid of it, the Edelbrock carbs are some of the easiest to work on. Just be real careful when you pull the top off so you don't tear the gasket, be patient and work it with a putty knife or something comparable. You'll see the float bowls and the jets.

 

[broncnaz]

Sounds like you have the classic symptoms of a gas tank full of crap. 45 minutes of driving then lose power. 2 weeks and the filter is plugged means lots of stuff in the tank its probably plugging up the pickup tube and causing your power loss. Id question if the mechanic really dropped the tank and cleaned it out or not. Worst case it was just your filter clogged up and if he cleaned the tank out you should be good to go. Drive it with a new filter for a tank or 2 see if it happens again.
Also electric fuel pumps work better when mounted close to the tank they are better pushers than pullers. But i dont think this is related to your problem.

While pulling the cover off your carb is a good idea I would pull the whole carb off and do it on a bench. There are a lot of small screws and pins that need to be removed any one of these could get into the engine or just lost. Also be very careful putting the cover back on that you dont bend the needles. A lot of people like edelbrock say they are easy to adjust/rejet on the engine well they are if you only need minor change which is not always the case other wise its better to remove it so you dont drop any thing.

 

[bblue]

I think that electric fuel pumps are better pushers than pullers I have always mounted mine close to the tank. I would drop the tank and flush it out. at least you can use the fuel pump to empty the tank before you remove it. I also run an inline filter before the pump.

 

[stingus]

Sounds like you have the classic symptoms of a gas tank full of crap. 45 minutes of driving then lose power. 2 weeks and the filter is plugged means lots of stuff in the tank its probably plugging up the pickup tube and causing your power loss. Id question if the mechanic really dropped the tank and cleaned it out or not. Worst case it was just your filter clogged up and if he cleaned the tank out you should be good to go. Drive it with a new filter for a tank or 2 see if it happens again.
Also electric fuel pumps work better when mounted close to the tank they are better pushers than pullers. But i dont think this is related to your problem.

While pulling the cover off your carb is a good idea I would pull the whole carb off and do it on a bench. There are a lot of small screws and pins that need to be removed any one of these could get into the engine or just lost. Also be very careful putting the cover back on that you dont bend the needles. A lot of people like edelbrock say they are easy to adjust/rejet on the engine well they are if you only need minor change which is not always the case other wise its better to remove it so you dont drop any thing.

He dropped the tank to check if the filter was clogged but did not clean it out b/c the filter was not clogged. I'm gonna drive it with the new filter tomorrow for about an hour so and see if it does the same thing. If so I'll probably order a 23 gallon main tank, bypass the valve/switch, and just use the main tank. I'll also mount the electric pump on the frame back towards the rear tank.
Never worked on a carb before, do the symptoms my bronco is having sound like I need to adjust it? Also, dumb question, where and what is the pick up tube?

 

[stingus]

I think that electric fuel pumps are better pushers than pullers I have always mounted mine close to the tank. I would drop the tank and flush it out. at least you can use the fuel pump to empty the tank before you remove it. I also run an inline filter before the pump.

Great idea, I was wondering how to lower a full tank. When dropping the tank is there anything specific i need to know or is it pretty self explanatory once i get under there?

 

[stingus]

If there's debris in the fuel system then it has probably made it's way into the float needle/seat assembly. The bogging could be the carb flooding because the needle can't close completely. Does it puff out black smoke when it happens?

I don't think its puffing out black smoke. I've got to read up a good bit before I'm confident to work on the carb.

 

[broncnaz]

Where the gas line hooks into the tank is a sending unit/pickup tube the tube has a filter on it(http://broncograveyard.com/bronco/i-10212-sending-unit-rear-1970-76.html) and when the vehicle is running the fuel gets sucked through that filter/tube if theres stuff in the tank then vehicle movement and constant sucking will pull debris into that filter eventully plugging it up to the point that little fuel is flowing which may not be enough fuel to keep the jets in the carb covered at 60 mph.
when a vehicle is parked for awhile that debris will fall off the filter and it will apear to be clean. Also I would suspect that filter on the pickup tube may have a hole in it or has fallen off if your getting debris in your filter down stream.

It really doesnt sound like a carb issue to me because if the fuel level is dropping to the point of power loss then the floats have also dropped(ie needle seats are open and fuel should be flowing in) which means theres not enough fuel flowing through the fuel pump to keep the carb full.
On the other hand there are filter screens in the carb sometimes theres one under the fuel inlet fitting but not always. But edelbrocks will have a small filter screen under each needle seat if there is a lot of debris in these it could cause the issue as well.

Carbs are very easy you just got to do it. if you have the manual or internet all the info is out there.

 

[stingus]

Where the gas line hooks into the tank is a sending unit/pickup tube the tube has a filter on it(http://broncograveyard.com/bronco/i-10212-sending-unit-rear-1970-76.html) and when the vehicle is running the fuel gets sucked through that filter/tube if theres stuff in the tank then vehicle movement and constant sucking will pull debris into that filter eventully plugging it up to the point that little fuel is flowing which may not be enough fuel to keep the jets in the carb covered at 60 mph.
when a vehicle is parked for awhile that debris will fall off the filter and it will apear to be clean. Also I would suspect that filter on the pickup tube may have a hole in it or has fallen off if your getting debris in your filter down stream.

It really doesnt sound like a carb issue to me because if the fuel level is dropping to the point of power loss then the floats have also dropped(ie needle seats are open and fuel should be flowing in) which means theres not enough fuel flowing through the fuel pump to keep the carb full.
On the other hand there are filter screens in the carb sometimes theres one under the fuel inlet fitting but not always. But edelbrocks will have a small filter screen under each needle seat if there is a lot of debris in these it could cause the issue as well.

Carbs are very easy you just got to do it. if you have the manual or internet all the info is out there.

One of the guys sent me a link to the manual. I'm gonna read up on it more tomorrow. A fellow bronco diver told me a bout a kit that removes the tank rust and reseals it. Im looking into that as an option as well. Less cash involved. However for simplicity's sake, a new bigger tank with new sending unit and and no selector valve sounds pretty good as a long term option.