Fuel pump?
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Fuel pump?
Hi again. I have had a problem with one of my fuel tanks since I have had the truck. When I switch to the front tank, after the lines clear, my truck will run very badly. It will run, just very badly alot of missing, surging etc. If I let it idle, it will eventually die, but will start again. I just want to make sure that is the problem before I spend the money. I haven't looked too far into the issue due to the squeeling some of you may already know about and the fact that I still have another good tank. but I am about ready to fix it. I did a search and got nothing, so I am coming to the pros again.
Thanks in advance
Damon
Thanks in advance
Damon
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Joined: Oct 2006
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From: Davis & Newcastle, CA
Generally speaking, if you switch to the other tank and the truck immediately starts to sputter (or dies) then you're talking about a bad fuel pump in that tank, since there isn't a lot of other places for failure in the circuit besides the dash switch itself. Clearly if you're still getting SOME fuel to the cylinders then your dash switch is obviously sending power to the pump. At that point the only place for failure is the pump itself.
You can see that between the switch and the pump itself there aren't any other places for failure.
You can see that between the switch and the pump itself there aren't any other places for failure.
Last edited by Skandocious; Jan 30, 2008 at 12:23 AM.
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shoot scandocious you know your stuff!! I have looked under there, and I see what you are talking about, but I just wanted to make sure it isn't the switch or some people say the sending unit. I have also been told that the sending unit just tells me how much fuel is in the tank. My guage works just fine.
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From: Davis & Newcastle, CA
Originally Posted by workd
shoot scandocious you know your stuff!! I have looked under there, and I see what you are talking about, but I just wanted to make sure it isn't the switch or some people say the sending unit. I have also been told that the sending unit just tells me how much fuel is in the tank. My guage works just fine.
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From: Davis & Newcastle, CA
Originally Posted by workd
shoot scandocious you know your stuff!
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Originally Posted by Skandocious
I know a bit about these trucks and I attribute EVERY LAST THING I know to the fine guys on this site. Stick around and you'll learn a thing or two
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Postmaster
Joined: Oct 2006
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From: Davis & Newcastle, CA
Originally Posted by workd
Good, I like to learn. So it wouldn't be a waste of money to buy a new fuel pump if I am not mistaken.
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Joined: May 2007
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From: Solon, Ohio
You might just have bad gas/water/contaminates in the one tank.
Try adding dry gas and running that tank empty, then filling with a couple of gallons of good gas, (you don't want to fill it too much if you might have to drop it to change the pump).
Try adding dry gas and running that tank empty, then filling with a couple of gallons of good gas, (you don't want to fill it too much if you might have to drop it to change the pump).
Laughing Gas
Joined: Oct 2001
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From: Winchendon MA
I'd say it's the pump too but take a good look at the conection points of the electricals on the top of the sending unit they can some times get coroded up and make intermidante conections thus varry the fuel presure.
Stay away from SPECTRA fuel pumps sold by the big discount on-line place. I had to change mine out twice with in a month! 1st time pump worked but the check valve was junk so rear tank would flow in to the front tank. In 96 the valve is in the pump. Swaped it out to get a pump that died a week latter drop and replace again so far so good i've got 12,000 on the pump now but i'd not recomend using spectra brand. Now i know why it was $90 and all the otheres were $150+
44
Stay away from SPECTRA fuel pumps sold by the big discount on-line place. I had to change mine out twice with in a month! 1st time pump worked but the check valve was junk so rear tank would flow in to the front tank. In 96 the valve is in the pump. Swaped it out to get a pump that died a week latter drop and replace again so far so good i've got 12,000 on the pump now but i'd not recomend using spectra brand. Now i know why it was $90 and all the otheres were $150+
44
Senior User
Joined: Nov 2007
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From: Naples, FL
yup if you really want to be sure just check the pressure at the rail....32 psi at idle and 42 at WOT is the correct pressures...I would go from there...also crap fuel is also high on my list...how old is the stuff in there??? and how much is in there??? old gas will settle and carmelize over time...this can clog many important parts...so if the gas is old I DONT suggest running it through as i can clog injectors and other things...if anything I would try to dilute it with a bunch of new gas to help it pass through the system without clogs...(but thats on a system I know works and I wont have to pull the tank)...I would suggest a pressure test and then we can go from there...
But it sounds like crap fuel...if you switch it it takes a second for that junk to make its way through the system...well I guess it could be a weak fuel pump as well...thats why it takes a second to run like crap and when you switch it it runs insantly (because the rear is good)??? hhhmmmm...I guess Ill leave that one to the ford guru's...Bill wanna chime in here???
But it sounds like crap fuel...if you switch it it takes a second for that junk to make its way through the system...well I guess it could be a weak fuel pump as well...thats why it takes a second to run like crap and when you switch it it runs insantly (because the rear is good)??? hhhmmmm...I guess Ill leave that one to the ford guru's...Bill wanna chime in here???
Last edited by codyingersoll123; Jan 30, 2008 at 10:27 AM.
Post Fiend
Joined: May 2004
Posts: 11,289
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From: Lakewood, Ohio
i said fuel filter because he never said he had ever changed it.
i do think it is the 2nd pump.
but that does not mean it is not a loose connection, a clogged pickup to one pump or a kinked fuel line from that tank.
i do think it is the 2nd pump.
but that does not mean it is not a loose connection, a clogged pickup to one pump or a kinked fuel line from that tank.
Fleet Owner
Joined: Aug 2005
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From: Easton,Ks
Originally Posted by codyingersoll123
yup if you really want to be sure just check the pressure at the rail....32 psi at idle and 42 at WOT is the correct pressures...I would go from there...also crap fuel is also high on my list...how old is the stuff in there??? and how much is in there??? old gas will settle and carmelize over time...this can clog many important parts...so if the gas is old I DONT suggest running it through as i can clog injectors and other things...if anything I would try to dilute it with a bunch of new gas to help it pass through the system without clogs...(but thats on a system I know works and I wont have to pull the tank)...I would suggest a pressure test and then we can go from there...
But it sounds like crap fuel...if you switch it it takes a second for that junk to make its way through the system...well I guess it could be a weak fuel pump as well...thats why it takes a second to run like crap and when you switch it it runs insantly (because the rear is good)??? hhhmmmm...I guess Ill leave that one to the ford guru's...Bill wanna chime in here???
But it sounds like crap fuel...if you switch it it takes a second for that junk to make its way through the system...well I guess it could be a weak fuel pump as well...thats why it takes a second to run like crap and when you switch it it runs insantly (because the rear is good)??? hhhmmmm...I guess Ill leave that one to the ford guru's...Bill wanna chime in here???
As you say check the fuel pressure at the fuel manifold and make sure it is around 32 at idle and 42 at WOT. If it looks good and you are still having problems then take it for a ride and tape the gauge to the windshield to make sure the pump is OK.
Yes more than likely a bad rear pump.
Does the rear tank fill with gas while running on the front?
You just have to maintain that 39-psi fuel pressure across the injectors, it can not go below or above 39 psi for it to run right.
Last edited by subford; Jan 30, 2008 at 11:17 AM.