Fuel Pump???

[theaddictedchef]

I was on my way home from work tonight and had the first (and only.....I hope) problem.  My truck acted like it was going to run out of gas.  Since I am in the process of redoing my gauges, I figured there was a problem with my gas gauge.  I stopped, got some gas, and the problem didn't go away. 

I feels like it wants to run out of gas - hesitates, and then goes, hesitates and then goes.  It stalled at a light but started right up.  I have dual tanks and ran the right side empty, switched over, and kept on going, but this is different.  Is this a fuel pump problem?  The beginning of a fuel pump problem?  Is this something different?  Can anyone tell by the limited info provided?  Not sure how else to explain it. 

Thanks......

[Fairlane514]

Is your pump mechanical or electric?    You can remove the line from your carb ( I assume its carbureted) Run a rubber line to a container and then turn the motor over (without starting it) and see if you have a healthy amount of flow.

May also be something stuck in your fuel inlet of the carburetor that is not allowing enough fuel to enter the bowl.

[theaddictedchef]

I thought all fuel pumps were electrical.  I am obviously mistaken.  If I have one or the other, does it make a difference?  Why?  I think you might be onto something with a clogged/partially clogged fuel filter.  Since I ran my tank dry, would that mix up some of the sediment on the bottom of the tank and possibly clog the filter? 

Thanks for the info so far.

[Fairlane514]

What year is your truck? Is it the original motor?  Look on the passenger side of the motor down at the bottom, near the front corner. The mechanical fuel pump would be right there, with a round looking top and some fuel lines coming in from the tank and one going out up to the carburetor.

Its possible you picked up some sediment, but there should be a "sock" on the line inside the tank to filter such sediment, but it to can deteriorate and let stuff get by.

Pull the filter (quadrajet?) and replace it, its cheap. You may have to rebuild the carburetor if some debris has gotten into the needle and seat, but this condition usually allows too much fuel in, causing a very rich problem. This doesn't sound like what you describe.

Do you smell a strong odor of fuel, near the pump area?

[theaddictedchef]

'73 with a 350.  Not sure about the original engine.  I THINK it is, but not sure.  No smell of fuel.  I'm not home but when I get home I can look at the fuel pump and see. 

[Fairlane514]

I can say with 99.9% certainty you have a mechanical fuel pump, unless someone installed an electric one.

Check the fuel filer, replace, and see if that fixes it.

[theaddictedchef]

Just talked to the PO and he confirmed mechanical fuel pump.   Got one located at autozone and gonna get a new filter at the same time.   

Thanks for the help!

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[Fairlane514]

I would buy an AC Delco brand and not Airtex etc... 

Do you know what carburetor?

[theaddictedchef]

Noted.....thank you.

[bake74]

     Did you get this resolved ?  Fuel filters are mostly made of a paper element, so as it start to get full it is harder for the pump to push fuel past the clog, this could explain the go, stall, go problem.

[theaddictedchef]

Update -

I replace the filters - both the fuel filter and the filter in the carb.  I replaced the ICM - one of the guys at O'Reilly's took an interest in my truck (he's a hot rod guy and seems knowledgeable) and told me that what it sounds like to him is the ignition control module (?) so I replaced that.  Inside my distributor is that ICM so I replaced that.  Ran great for about 30 miles and then right back to the same problem.  It sat for a day and a half while I worked on it and now right back to the same sputtering - running out of gas type thing. 

I may replace the fuel pump just to be safe, but I took the fuel pump off, messed with it and it seems to have good suction and looks like it was replaced recently (?). 

Another note - could this be something plugging the fuel line from the gas tank?  I've got dual tanks and run one dry and then switch over.  I am thinking that maybe I have sucked some sediment up from the tank and when I switched over it clogged the fuel line.  As it sits, that dirt/sediment works its way down and then as I drive it gets back up in the fuel line.  Just a thought.

I changed my spark plugs and put in the AC Delco plugs.  Changed the ICM.  Put the old fuel pump back in (and will change that Tuesday morning).  I'm frustrated about this and really don't want to drop my fuel tanks and run new fuel lines - is that where I'm headed? 

I also replaced my blower motor with the '94 that many have posted about.  Also - tableside bananas foster for your enjoyment! 

Thanks for the replies dudes - it helps a ton!

[Fairlane514]

You can disconnect your outlet line from the pump (it connects to the carb) put a rubber hose on the end and then into a gas can. Disconnect the 12 volt source to your coil on the distributor, and then crank the motor and see if the pump is pumping enough fuel. Should be a pretty strong steady stream of fuel coming out.

[bake74]

You can disconnect your outlet line from the pump (it connects to the carb) put a rubber hose on the end and then into a gas can. Disconnect the 12 volt source to your coil on the distributor, and then crank the motor and see if the pump is pumping enough fuel. Should be a pretty strong steady stream of fuel coming out.

     This is the way to check your pump flow.
     As far as the lines and plugging, you could be right, especially at the switching valve.  What I would do is disconnect each line at both ends ( one at a time, from front to back or vise versa ), and use compressed air to blow them out ( make sure you are blowing out only the rubber line only, not through your valve or tanks, you could damage the float mechanism if you use compressed air to blow into your tanks ).  ( Check each hose to see if something blew out )
     Then I would take off your switching valve and check to make sure it does not have something plugging it. 
     I am assuming that it happens with both tanks, which tells me it is not the pick-up tubes in the tanks.  If only 1 tank did it and not the other, I would say start with that tank and pick-up tube and hose to switching valve.

[theaddictedchef]

Okay.   Thank you.   Getting ready to start wrenching now.  Should be a fun day.  I have really enjoyed this and I'm excited about fixing this and having a truck with character.   

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[theaddictedchef]

Okay boys, new information......

My truck is dead at Cirlce K around the corner.  I pulled the fuel line off and cranked the engine - a good amount of fuel comes out so I am confident that it isn't the fuel pump. 

The filter has a ton of dirt in it and that makes me concerned as I just replaced it three days ago.  I can step on the pedal and as long as I don't get on it, it runs fine, idles fine but as soon as I step on the gas, even to go a third, the truck dies.  Now it won't even turn over. 

My thougts are that I sucked up a bunch of dirt from the tank and that is now plugged in the fuel lines, or the carb.  If it's the carb, how big are my troubles?

As always - thank you for the posts.......