fuel pump or blocked line??

roparsons · Jan 28, 2010

I pulled my fuel line off of the filter and pumped the gas pedal and got nothing. The filter is not clogged and I am trying to figure out why I am not getting any gas to the carb. I know on my Tahoe I have to drop the tank to get to the fuel pump, is it the same on the Bronco?? Will I have a pump in each of the tanks?? Is there an easy way to test the pump and fuel lines??

Again, thank you all!!!!

bigbadktm · Jan 28, 2010

my fuel pump is on the block, unless you have an electric pump. the fuel pumps are driven off the cam i believe, but I am fair bit of a newbie myself

gtownky · Jan 28, 2010

What year is your bronco? Does it have electric fuel pump or manual? If it is a manual pump then disconect the fuel line from the carb and pour fuel in the line. Have someone crank the engine. If fuel shoots out then the pump is ok. If electric, disconect at the filter and turn key to on position. If fuel starts to pump out on the ground then pump is ok. If manual fuel pump, check to see if the rubber fuel lines has cracks in them. If so you are loosing prime from the manual pump and will not be able to get fuel up to the carb or filter.

NJB71 · Jan 28, 2010

roparsons said:
I pulled my fuel line off of the filter and pumped the gas pedal and got nothing. The filter is not clogged and I am trying to figure out why I am not getting any gas to the carb. I know on my Tahoe I have to drop the tank to get to the fuel pump, is it the same on the Bronco?? Will I have a pump in each of the tanks?? Is there an easy way to test the pump and fuel lines??

Again, thank you all!!!!

pretty sure if your running a carb there is no fuel pump, in tanks or on rail, but rather pulls off the engine, mechanical runs from timing chain.....no gas in carb bowls? only thing I can thibk of is some heavy duty clogging on the sender in the fuel tank(it has a filter on it) its located above the rear diff and has wires running to it(its justa float), u can unscrew it and check if its clogged

DonsBolt · Jan 28, 2010

with the line off, have someone turn the key, and see if gas spurts out of the fuel line. If it does the pump should be good. If thats tthe case I would then look at the needle/seat on the carb.

If you have a stock fuel pump it is on the drivers side of the block, allmost all the way foward. And just held on my two bolts
If the pump is bad, they are cheep and easy to change

I assume you have a 302, if so here is a good stock replacement pump, Also make sure the selector valve for the tanks are in the right position, not just the switch on the dash for the gauge.

http://www.summitracing.com/parts/CRT-M6588/

broncnaz · Jan 28, 2010

You shouldnt get anything out of the fuel line if you pump the gas pedal. The only time you will get gas coming out the line is when the engine is cranking. Follow the fuel line from the carb does it run down the side of the engine block and hook in there? If so thats the mechanical pump.
Since you have 2 tanks make sure the selector switch( its near the floor on the driverside) is turned to the tank that has gas. Sometimes the selector valve fails and will not switch between tanks You could by pass the valve to see if the fuel pump will pull fuel if not then you may need to check your fuel pickup in the tanks. Also check all the fuel hoses and lines make sure they are in good condition.

fatboy · Jan 28, 2010

Mechanical fuel pumps rarely fail all at once, usually you start loosing RPMs and you speed continues to drop over a time of a minute to minutes. If that is the issue then it is likely a pump though a clogged filter in the carb has done this to me as well before. Like Don said, disconnect the fuel line at the carb and crank it over. If you have fuel there you need to look at the carb. If not you will need to move back.

Basic question, is there fuel in the tank?

Action · Jan 28, 2010

Leak

Also if it is the fuel pump they almost always leak when they go out.
Jack

68broncohalfcab · Jan 28, 2010

what year is your bronco, 68 and earlier have a different fuel pump than a 302 and has vaccum lines to it and cost a lot more than a 302 pump. check your oil to see if gas is in the oil pan. sometimes when the diapham fails fuel goes into the oil pan thru the block.

DonsBolt · Jan 28, 2010

Action said:
Also if it is the fuel pump they almost always leak when they go out.
Jack

hehe not allways sometimes they just let go
One bit of advice, stay away from Holley fuel pumps, they like to do this

roparsons · Jan 28, 2010

Thank you for all of the responses...I have some great things to go on. To answer some of the questions from all the responses in just a couple of sentences: The Bronco is a 1975, I have fuel in both tanks, I just added 10 gallons new fuel to the main and 7 gallons to the aux. I have no idea if it is an electric or mechanical pump right now (I probably should know that), I didn't get any fuel pumping out of the line when I turned the key but I will try again tomorrow and let it rev longer.

gtownky · Jan 29, 2010

Im guessing it is a manual pump. Disconnect fuel line at the carb and get a funnel. Pour some fuel in the end of the line and have some get in the bronco and try to start the truck while you are watching the end of the line that you are keeping in the air above the fuel pump. When they try to start it. Fuel should the fuel you poured in the end should start to pump back out the end of the line. If so the pump is good and then you need to replace the rest of the fuel lines to the tanks because they are cracked and have are loosing their prime.

Gregg · Apr 10, 2011

same problem

I have a 71 bronco that all of a sudden wouldn't start this morning. She pulled into the garage a couple of days ago w/o any fuel concern. Starter/battery were great and I thought I just flooded it. But when I tried later it still didn't start. I looked in the carb and it was pretty dry and no strong fuel smell. Figured I had a clogged filter or bad fuel pump. Went to Adv Auto and got the filter and looked at the 302 mechanical pumps. Although I have a 71, the engine was swapped by the PO with a 84 mustang GT 302. Adv Auto had the 71 302 pictured above but the one I took off looked pretty new and has a smaller diaphram. They ordered the 84 pump for me but how much will it matter? Should I stay with the smaller one or go with the bigger one(pictured above). You know, biggers better, right?
Any other advice is also very welcome! Thanks!

NYLES · Apr 10, 2011

Mine would run great long as it had 1/2 tank or better, bad pump drove me nuts!!!!! 1/2 tank had enough hydraulic pressure to run it W/O a working pump.

69for5 · Apr 11, 2011

Possibility the fuel eccentric is loose. Its behind the timing chain cover held on by one bolt. If that bolt is loose the eccentric wont push the fuel pump rod up and down and no juice will flow. Hopefully its not that, kinda a pain in the butt to repair for just one bolt. If so, don't forget the locktite.

tnwrangler · Apr 11, 2011

Man, that's what I am doing today, replacing the fuel pump. With all the checks at different locations, I smell like a gas station. Tracked it down to the problem being the fuel pump. My pump is not leaking and I have been told letting the rear tank run empty, then switching over to the front tank, is what the cause of my problem would be with a 3 year old fuel pump.

NYLES · Apr 11, 2011

tnwrangler said:
Man, that's what I am doing today, replacing the fuel pump. With all the checks at different locations, I smell like a gas station. Tracked it down to the problem being the fuel pump. My pump is not leaking and I have been told letting the rear tank run empty, then switching over to the front tank, is what the cause of my problem would be with a 3 year old fuel pump.

mine was junk pump from day 1!

Explorer · Apr 11, 2011

tnwrangler said:
Man, that's what I am doing today, replacing the fuel pump. With all the checks at different locations, I smell like a gas station. Tracked it down to the problem being the fuel pump. My pump is not leaking and I have been told letting the rear tank run empty, then switching over to the front tank, is what the cause of my problem would be with a 3 year old fuel pump.

Bull! No way that caused a pump to fail.

broncobilly72 · Apr 11, 2011

One other thing...make sure the valve handle below th front seat is either to the left or to the right, not straight up. I had that happen some years ago and it took me a while to figure out the obvious.

fuel pump or blocked line??

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