Bronco Wont Start.. Fuel Pump? Gas Line?

[TxBronco66]

Hi All,

I am a brand new to the EB world. I finally got my hands on an 1966 Bronco with the 170 straight six engine. Today I changed the battery, oil, spark plugs, fuel filter, and the oil filter. The truck wants to turn over but it doesn't seem to be getting enough fuel(IMO). I did notice that the one of the hoses coming from the fill spot (the smaller one that connects to the side of the gas tank) is complete shot and cracked. Would this cause the fuel shortage to the carb? Could it be the fuel pump? Any and all input is greatly appreciated. Thank you all for your time and God Bless.

 

[Broncobowsher]

The one you are calling small, about the size of a heater hose? That is part of the filler neck, nothing to do with fuel delivery to the engine but should still be fixed eventually.

So you think it isn't getting fuel. Have you taken the air filter off and cycled the throttle quickly and looked for a spray of fuel out of the accelerator pump squirter? Have you tried using some carb cleaner and spraying some into the carb to fuel it? Just make sure you use the flammable type of carb cleaner, the non-flammable carb cleaner doesn't work as fuel.

Really you could be dealing with just about anything. Thinking it isn't getting fuel doesn't really mean anything. You need to check.

 

[El Kabong]

Whenever an engine won't start it is time to go to the basics. An engine needs 3 things to run:

• Fuel (Specifically a proper air fuel mixture).
• Spark (Properly timed)
• Compression

You want to narrow down which of those is the cause before changing anything else, since changes can cause multiple problems. multiple problems are harder to diagnose.

Fuel is probably the easiest to check. With the ignition off, add a few drops of gas or spray a little starter fluid down the carb. Set the gas or fluid aside prior to cranking the engine. If it fires for a few seconds & dies, it indicates lack of fuel.

Spark is next. Pull a plug wire, connect it to a test plug which is clipped to ground, & watch for spark while cranking. There are other methods using a screwdriver, or sliding a boot up & holding it close to ground, but anyone who has ever used those methods at some point has found spark by feeling it. Usually only once. I joke about having a helper hold the screwdriver, & I crank the engine & watch for him to jump & yell to see if there is spark. The other ways work. The clip on tool is just easy to use & hurts less.

Non HEI version

Compression is the least common issue. If it is a major compression loss, like when you have with a slipped timing chain, the engine will crank unusually fast. It sounds different. You can check compression with a gauge that connects to spark plug holes, but normally you check spark & fuel first.

It sounds like you did some tune up work. Be sure the spark plug wires are in the correct firing order. It is very common to mix them up when doing tune up work.

Was it running before? How long has it been sitting? When you are trying to start an engine that has been sitting, there are some extra steps that can help get it running. A lot of them are covered in this thread.

The hose you described doesn't sound like it would cause a no fuel situation. but you will want to change any of the gas hoses that are cracked anyway. The Bronco vendors in the ads at the top of the page should be able to provide them.

 

[broncnaz]

When was the last time it ran? its not uncommon to take a lot of cranking before fuel makes it to the carb on engines that have sat awhile. You may want to prime the carb by either pouring fuel into the vent tube or unhooking the fuel line and hooking another line thats hooked to a bottle that you can raise above the carb and allow fuel to flow into the fuel bowl. Once full hook the line back up from the pump.
Once the fuel bowl is full you should get enough run time for the fuel pump to pick up fuel from the tank and it should run on its own. If not maybe try it again if still wont run on its ow then the fuel pump may be bad or you have a issues somewhere else in the fuel system.

 

[TxBronco66]

The one you are calling small, about the size of a heater hose? That is part of the filler neck, nothing to do with fuel delivery to the engine but should still be fixed eventually.

So you think it isn't getting fuel. Have you taken the air filter off and cycled the throttle quickly and looked for a spray of fuel out of the accelerator pump squirter? Have you tried using some carb cleaner and spraying some into the carb to fuel it? Just make sure you use the flammable type of carb cleaner, the non-flammable carb cleaner doesn't work as fuel.

Really you could be dealing with just about anything. Thinking it isn't getting fuel doesn't really mean anything. You need to check.

I have taken the air filter off and cycled the throttle quickly, however it only squirted once and would not squirt again. I also tried the carb cleaner and it fired up for a split second and shortly died. What do you think? Sorry, I'm such a noob.

 

[TxBronco66]

Whenever an engine won't start it is time to go to the basics. An engine needs 3 things to run:

• Fuel (Specifically a proper air fuel mixture).
• Spark (Properly timed)
• Compression

You want to narrow down which of those is the cause before changing anything else, since changes can cause multiple problems. multiple problems are harder to diagnose.

Fuel is probably the easiest to check. With the ignition off, add a few drops of gas or spray a little starter fluid down the carb. Set the gas or fluid aside prior to cranking the engine. If it fires for a few seconds & dies, it indicates lack of fuel.

Spark is next. Pull a plug wire, connect it to a test plug which is clipped to ground, & watch for spark while cranking. There are other methods using a screwdriver, or sliding a boot up & holding it close to ground, but anyone who has ever used those methods at some point has found spark by feeling it. Usually only once. I joke about having a helper hold the screwdriver, & I crank the engine & watch for him to jump & yell to see if there is spark. The other ways work. The clip on tool is just easy to use & hurts less.

Non HEI version

Compression is the least common issue. If it is a major compression loss, like when you have with a slipped timing chain, the engine will crank unusually fast. It sounds different. You can check compression with a gauge that connects to spark plug holes, but normally you check spark & fuel first.

It sounds like you did some tune up work. Be sure the spark plug wires are in the correct firing order. It is very common to mix them up when doing tune up work.

Was it running before? How long has it been sitting? When you are trying to start an engine that has been sitting, there are some extra steps that can help get it running. A lot of them are covered in this thread.

The hose you described doesn't sound like it would cause a no fuel situation. but you will want to change any of the gas hoses that are cracked anyway. The Bronco vendors in the ads at the top of the page should be able to provide them.

When was the last time it ran? its not uncommon to take a lot of cranking before fuel makes it to the carb on engines that have sat awhile. You may want to prime the carb by either pouring fuel into the vent tube or unhooking the fuel line and hooking another line thats hooked to a bottle that you can raise above the carb and allow fuel to flow into the fuel bowl. Once full hook the line back up from the pump.
Once the fuel bowl is full you should get enough run time for the fuel pump to pick up fuel from the tank and it should run on its own. If not maybe try it again if still wont run on its ow then the fuel pump may be bad or you have a issues somewhere else in the fuel system.

Kabong- I labeled all of the wires prior to disconnecting them to ensure they went back to the right place. I was told that it has sat for close to a year and half without being started. I will try the screwdriver trick tomorrow. Thanks for your time and input. Hopefully I can get this figured out.

broncaz- It ran about a year and half ago from what I am told. I will definitely try the bottle trick tomorrow when I get off of work. Today I tried multiple cranks and tries until the battery started to loose charge. Thanks for the Info, I'm still new at this and you guys are awesome.

Thanks for all of the input guys. I will keep y'all posted on the situation.

 

[Justafordguy]

Welcome to the site. It does sound like a lack of fuel if the carb spray made it fire up for a second. X3 on filling the carb bowl up with fuel. This should make it run long enough to prime the fuel pump. If not you may have a bad pump or clogged line to the tank.

 

[El Kabong]

I have taken the air filter off and cycled the throttle quickly, however it only squirted once and would not squirt again. I also tried the carb cleaner and it fired up for a split second and shortly died. What do you think? Sorry, I'm such a noob.

This ^ indicates that you have a fuel issue. If you had no spark it wouldn't have fired up even for a little bit. No need to test for spark.

As mentioned above pouring a little gas down the vent can get enough fuel in there to run it long enough to prime the pump. Most won't prime just by spinning the starter. Getting it to run on a little gas or starter fluid helps to get it primed. If it doesn't go in its own after a few tries with added fuel, then it is time to start tracing down the cause.

I use an old lawnmower gas tank for firing up carbureted engines with fuel issues. I put it on a blanket on the roof & run a line directly to the carb. A line from the fuel pump is run to a gas can on the ground to capture any fuel if it starts pumping. You have to be careful running the engine with open fuel lines around, & keep an eye on the can so it doesn't overflow. This way I know I have new good gas & pressure to the carb. If I don't get fuel thru the carb at that point, I know I have a carb issue.

If it runs ok on the gravity feed & still doesn't pump gas from the fuel pump, I connect my mini tank before the pump & reconnect the pump to the carb. No gas at this stage points to a pump issue. Running good indicates something further upstream. Maybe a hole in the line, clogged pickup or line, pickup too high, etc.

 

[snowymtnwolf]

Dude it worked. It's alive. Almost finished with 77 restoration and let it sit for 1 month, longest ever. Tried everything and then had to fill fuel bowl (clear plastic thing) and voila. Thread is almost 10 years old but still relevant. Thx much.

 

[DirtDonk]

haha! Nice to hear the info archive is still working! Way to pull up old info, but way to go getting your Bronco running. Congrats.

Hopefully to have fun for the next few months at least.

Paul

 

[El Kabong]

Dude it worked. It's alive. Almost finished with 77 restoration and let it sit for 1 month, longest ever. Tried everything and then had to fill fuel bowl (clear plastic thing) and voila. Thread is almost 10 years old but still relevant. Thx much.

Glad you got it. Congrats on getting it running.