Whys isnt my fuel pumping?!?!?!?!

OK this may be a l***le long but I want to try and give out all of my symptoms/problems.

So I posted awhile back about my truck starting and then quitting real quick but after awhile it would start and be ok. So this Friday I get home from out of town and this time it would even come close to starting, however the engine was turning. Maybe an ignition problem...checked everything, spark, battery all and it was fine. I looked into the carb (Holley 750 4 barrel) and seen that fuel was getting sprayed into the carb. So must be fuel filter...changed it out, then changed the fuel pump. Got home installed the new fuel pump and BAM it started over like a champ.....for about 10 seconds and then quit. I noticed now I have no fuel getting sprayed into the carb. and hell the new pump and lines were not even wet. Seems the pump cannot pump the fuel from the tank to the carb.

OK maybe someone stole the gas out my truck while Im gone during the week...nope filled a jug and filled it up..nothing. I filled the carb up with gas and started it to hopefully get some prime back in the truck to **** the gas but nothing..Im scared to continue this process without screwing the truck up.

Here are some of questions/thoughts on this and please tell me if Im wrong or its just something different...whatever.

1.) How do you check to see if a pump is working or if one is bad with it out the truck. I pumped it by hand and actually both the new and original seem to **** and push air out pretty good. Maybe I got a ****py pump and within no time it blew out?

2.)A fuel pump pushes the fuel to the carb but the secondary va***n on the pump is for????

3.)My cast numbers is C8AE-H..so that a 68 427 block????? Would a 390 fuel pump be the same as a 427 pump, seems it would right? (Hope I dont get the stupid sign for that question) Just wondering if the new fuel pump just isnt as tough...

4.) I took the line off the out side of the pump and tried to start it...no fluid at all...is that a good test for a pump and if there is nothing would the pump be bad?

5.) I noticed markings on the pump lever...what device actually hits this to keep the pumping of fuel? another stupid question...

OK i think that should be good enough. So whats your thoughts on this....NO Fuel???? oh yeah and last week it drove great and had to problem to even start when in the past its been a little difficult....

Its a 1962 F-100, FE 390, Holley 750 Carb....ok let the opinions/past experinces flow....I already missed one car show because of this...I dont have as much experince as some so thanks in advance.

 

Pour some gas into a container and run a hose from the fuel pump into it and see if anything comes out the other end...

How old is the tank?

Take the hose off the inlet side of the fuel pump and blow into it, have someone else put there ear to the filler tube on the tank and see if they hear any bubbles...

 

I sorta did that when I took the hose off the outlet and cranked it...nothing. Im wondering if just maybe that new pump is ****. I mean it started beuatifully right when i put the new one in and then quit....all lines dry as a *******. I will try the air into tank way as well though but now I have a full tank and not sure if I could get that much pressure into it.

 

You just wanna see if you can hear some bubbles in the tank to see if it's clogged or not.

If you've got an air compressor you can blow some air through the line that way. But go through the line into the tank only, not through the pump..

 

yeah...i was thinking that when I took the hose off the hard line from the tank no gas came out...should it come out if I undid the clamp...its gravity fed sicne the fuel pump is on the outside...right? Sorry I may sound like a novice...since Iam one but you get what Im saying...maybe its just trash in there.

 

If your car has a fuel pump, it's not gravity feed. Some fuel lines will siphon and dump the tank when the pump is unhooked, but not all.

The reverse air line trick (gas cap off) is the first place to start. If you hear bubbles, then it's time to put gas in a container under the truck and see if the pump will pick up fuel from that.

Right now you don't know if the pump can't pull because of line/tank issues, or if there's a mechanical issue like the engine's eccentric lobe that drives the fuel pump.

good luck

 

OK got ya...I understand. So when the truck did start right after I put the new pump in for about 10-15 seconds that was a result of what was left in the line? The pump feeds the furl all the way to the carb and the secondary va***n at the carb is for_____, what?

With that I may think that the carb is working but the pump is not taking the fuel from the tank to the carb.

This may sound even more FNG but the lobe is the actual part that initiates the pump to work right? I take it I dont even want to know what it takes to replace this do I? ahahah damn damn

I will try the container under the truck with fuel and drop the line in there. If it works then its obvious I have some trash or blockage in the tank...god I hope thats it

 

A carburetor will run for up to a minute on the gas it holds in the float bowl. Depends on the carburetor as to how much it holds, how long it runs.

In fact, I'd dribble about 1/3 an aerosol lid worth of gas down the carburetor bowl vent before trying any more fuel pump testing. (looks like an open tube coming out the top, 1/4" diameter), Like any dry pump, it's gonna take a few seconds to prime. The engine will start and rev for a few seconds on what you're putting in the carb manually, pumps prime WAY better at 2000 rpm than cranking speed.

Safety note- any time you're pouring gas into the carburetor, don't start it without an air cleaner. Backfire might equal flaming gas droplets. Also don't do ANY of the testing involving a container of gas without a fire extinguisher handy.

Good luck

 

well dman...i did the gas in the carb starts yesterday and never did put the air cleaner on. it would start for a second and then just quit. I probably didnt put enough gas in the carb. Either way this gives me more reason to believer that something may be in the tank and stopping the fuel from actually coming to the pump...the hard line is bone dry evern after priming it several times...I really hope noone stuck something in there being a **** or something.

 

Are you running a vented cap on the tank?

I'm not sure if the symptoms would manifest themselves as quickly as they are, but it's possible, often mistaken for rusty lines or bad fuel pump.

 

[quote="Whitey Ford" 62 Uni;3201811]I really hope noone stuck something in there being a **** or something.[/quote]

20 years ago friend scored a great deal on a GTO with a fresh performance motor built & installed by a local speed shop. Guy drove it 50 or 60 miles and got mad because it had half the power it used to, then parked it for a decade.

Once my buddy extracted half a busted golf tee from the fuel pump's feed line, car ran GREAT. Apparently the shop used tees to plug fuel lines during the swap and broke one in the line.

As they say, devil's in the details.

 

No i have a flat sealed cap. I will try and start with the cap off later (work out of town during the week) but seems not to matter since it started great....for 15 seconds...damn thing.

 

The wierd thing is there is absolutely no sign of any fuel coming through...i mean none...maybe its just that stopped up or someone did put something big in there. I know the way my driveway sits its at a little bit of a backwards angle so whatever is left in the line is going the opposite way of the pump...

"Devils in the details"...i like

 

Not much I can add as Shifty has pretty well nailed it as usual.

I think you are on the right track in thinking that there is something plugging the pickup tube in the tank. You might also check the lines from the tank to the fuel pump to make sure you don't have a cracked hose ****ing air.

BangerMatt's question on the cap is also good as I have had problems with caps that were supposed to be vented not being vented in the past. Usually the problem shows up a mile or so from then house and it acts like the truck/car runs out of gas. When you open the cap you hear it **** in air and the sides of the tank pop back out from being ****ed in by the fuel pump. It took me a walk to the gas station and back to figure that one out. If you have swapped caps recently that might be an issue.

I'd follow Shifty's directions and blow back through the fuel line until your helper can hear bubbles at the filler neck. Hook up the line to the pump, fill the float bowl (s) and start the engine and see if it will pick up the fuel from the tank.

One thing that I and several others on here do is to put an inline filter between the tank and the fuel pump to catch any trash that the pump might pick up out of the tank, The filter will plug up but will catch most of the stuff that might get in the pump and kill it.

 

Cool deal. I will defiently try all of these applications. With the truck actually starting for a good bit after putting the new pump in it seems to me the problem is before the pump as yall are stating as well. I also think this because the new fuel filter, new lines are completely bone dry after SEVERAL attempts to get that thing primed and im scared i may damage more with dry starting so many times. Oh man working out of town ****s..now all week Im going to be wondering if thats the problem and if not then what are my other options...what the chance of having my girl go out there and take the hose off and blow to see if she hears bubbles in the gas tank???? yeah I think im just going to wait till i get home. Hell she was scared to turn the ignition when i was putting gas into the carb(thats when I though maybe I lost all prime)...anywho I really appreciate everyones comments on this and I hope that its solved this weekend.

 

It's a mechanical fuel pump right? Is it possible that the cam (or whatever in your case) is worn down to the point that it's not pushing the fuel pump enough? I know my father had that problem on one of his old trucks, the numb that was supposed to push the fuel pump was worn down and it didn't pump correctly, he had to change to an electric fuel pump.

 

That was what I was wondering as well. It is a cam and I checked out the wear marks on the fuel pump (yes mechanical) and was thinking the same thing...its just still werid that it fired up so quickly after I changed it and then its back to nothing. Also when installing a fuel pump you actually have to slide the lever in the cam notch and push up a little to match the threads...if thats the case then it seems that the cam IS hitting the lever ...am I right in saying this? SO if I had to raise the lever while trying to line the bolts then that should be functioning the way its suppose to. Once again....I think this is how it operates..

 

You're on the right track. Isolate the problem to being either a supply problem to the pump or the pump itself with the gas can trick. Take a couple of minutes and pull that pump off and check the cam lobe and make sure you are putting the pump arm on the correct side. Also with as much gas as you're pouring down the carb, check your plugs...Good luck and let us know what you find.

 

Guys...I have another question. I bought the fuel pump from Autozone and it was like 40 dollars. As I research a little more into this Im noticing that fuel pupms for the FE's are like 120 dollars. This pump fitted fine but ya think maybe this fuel pump just doesnt have anough pressure for mine. I do have a small cam and a Holley 4 barrell...or is this another new guy question? ahaha

 

Start with the cheaper fixes. Blow air back throug through the fuel lines. Hook up a gas can to a piece of fuel line, eliminating the tank and fuel line issues. Check the fuel cap.

There were many different fuel pumps issued by ford, possable you got the wrong armed pump.

I once had a Corvette that sat for years before I got it. The gas had completely dried up in the tank, lines, and filter. Cleaned the entire system. It would start and run for a bit, then would drastically loose power and stall. Restart and repeat. Turned out that a large piece of dried gas that was stuck in the line would flip up and act as a valve and then after sitting for 2 minutes it would fall back down flat. Restart and the piece would flip back up close off the line and stall. I ended up pushing a stiff wire all the way through the fuel lines to break uo the scaled gas to get it all cleared up.

 

Ya know I was looking at the pump when I got it and the original had a good thick piece of metal with a spring under the lever...the new one (probably made in china) didnt have all that good bracing but the lever was pretty much the same. But lets be honest some of the people at Autozone arent really trying help you out that much...well I should say the one by my house...I dont like to generalize.

 

I like the idea of running a hose from the suction side of the pump to a gas can. It's pretty easy to do and that may eliminate anything upstream of the pump to and including the original tank. If it runs like that then you know where to look...cracked hose, plugged fuel line etc. between the pump and the gas tank. A pin hole anywhere in that line will prevent the gas from getting ****ed up into a good pump

If it still doesn't pump then you need to check the pump and whatever powers the pump. Depending on the engine it might have a loose fuel pump eccentric on the timing gear.

 

METHINKS you solved your own dilema when you said you removed the gas cap(unvented) & heard a SWOOSH sound, try leaving the cap off comepletely & see if engine runs normal for 5 min.----If it does----Replace cap with vented one!!!-------------Don

 

Well I only did that to make sure I actually had gas in the tank...i was wondering if someone stole my gas since last week Atlanta had no gas aorund for 10 days after the hurricane. I was out of town and you know how thieves are. ANyway I will try with the cap off as well.

Damn I wish I didnt work out of town.

 

Question is, was the "swoosh" sound air going in the tank from a vacuum or air escaping in the form of pressure from fuel vapor buildup? Careful with putting air through your lines that you don't pop the sock off of the pickup. Just do the gas can trick to isolate the problem.

 

FE's have a bolt on eccentric that attaches to the front of the cam and the fuel pump arm rides on that. I suppose that could be loose.

If it pumps fuel from a gas can on the ground, that will rule that out.



[quote="Whitey Ford" 62 Uni;3201602]
5.) I noticed markings on the pump lever...what device actually hits this to keep the pumping of fuel? another stupid question...
[/quote]

 

No i meant i took the cap off and shook the truck to make sure I did have gas and wasnt relying on the gauge alone..sorry for the confusion. Im going to try the gas can and straight hose to the pump but Im wondering if I should get the high perfromance pump anyway...im a little worried about a typical autozone pump since it fits a few different blocks and mine is a little more upgraded than stock. Either way Im going to try the gas can trick. I have to wait till friday though...damn. I really really hope its nothing more than that.

If not then my next question is how do I change/tighten the eccentric. Sounds like a hoist is involved...

 

Start from the begining... Not starting? Take the fuel line off the carb and have some one turn the car over... No fuel coming out of the line? Take the line off the pump and have someone turn the car over... No fuel from the pump? Disconnect the pump and blow through the line into the tank while someone else listens for bubbles...

No Bubbles? Your tank is probably clogged...

Hear Bubbles? You probably got a bad fuel pump...

You just gotta go down the line from the most obvious to the least obvious, you'll find the problem sooner or later.

 

So what ended up happening?

Work anything out?

 

To solve a problem try to devide it in half. ie: Take a can with fresh gas put a hose in it, connect the hose to the inlet side of the fuel pump. with the carb side disconeccted place a hose on the output of the pump into another can.
Turn the motor over It should pump from one to the other. If it does the problem is towards the tank. If there is a fuel filter between the pump and the tank remove it if there is fuel in the tank Pressureise the tank (Be carful) fuel sould come out. If not keep going to the tank.