Another Fuel Problem
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Another Fuel Problem
I am new to the forum, so hello to all. I have a fuel pump problem.... and a throttle problem.
I recently purchase a 1993 F150 with the 4.9L and a 5 spd. And it has the infamous "dual tanks." So here is my problem, the rear tank's pump runs fine. I turn the selector to REAR and turn on the key, I hear a whirrrrr and I can tell the pump build pressure. No problem there the truck runs like a sewing machine. But, if I turn the selector switch to front and turn on the key I hear a louder sound from the front pump and it doesnt sound like it builds up pressure. the truck will not run off this tank. The sound is constant and the same level until the pump turns off after a few seconds. I also know that the front tank is completely full and its is full of old stanky nasty gas. Can any one help me? Is it possible that a line has become disconnected inside the tank? Or is it the calssic FUEL PUMP PROBLEM?
I also have a throttle problem. When I go to pull of from a stop ( when the engine is just idleing there is a dead spot right above idle where the truck tries to go dead. It is very small but it causes the truck to surge when you shift from 1st, 2nd, and 3rd. After 3rd it isnt really a problem because Im going down the road. I am thinking TPS am I close?
I recently purchase a 1993 F150 with the 4.9L and a 5 spd. And it has the infamous "dual tanks." So here is my problem, the rear tank's pump runs fine. I turn the selector to REAR and turn on the key, I hear a whirrrrr and I can tell the pump build pressure. No problem there the truck runs like a sewing machine. But, if I turn the selector switch to front and turn on the key I hear a louder sound from the front pump and it doesnt sound like it builds up pressure. the truck will not run off this tank. The sound is constant and the same level until the pump turns off after a few seconds. I also know that the front tank is completely full and its is full of old stanky nasty gas. Can any one help me? Is it possible that a line has become disconnected inside the tank? Or is it the calssic FUEL PUMP PROBLEM?
I also have a throttle problem. When I go to pull of from a stop ( when the engine is just idleing there is a dead spot right above idle where the truck tries to go dead. It is very small but it causes the truck to surge when you shift from 1st, 2nd, and 3rd. After 3rd it isnt really a problem because Im going down the road. I am thinking TPS am I close?
Last edited by IB Tim; Jan 30, 2006 at 06:52 AM.
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From: Bonita Springs FL
bmazingo -
You need a fuel pressure gauge to determine if the front tank isn't putting out enough pressure. If it's full of nasty old gas, I'd drain it first, fill it with fresh gas, and then buy a new fuel filter & install it.
Then use the pressure gauge to see if you have a weak pump. If it's weak, it's got to come out. I had one weak pump in an old truck of mine and I pulled the bed off and replaced both tanks. It worked great right up until the truck got wrecked less than a year later.
It also sounds like you have the idle problem identified. The first thing I'd do is put a new TPS on it.
rick - you'd be better off starting a new thread for your problems. When two users start talking about two similar problems in one thread, it gets very hard to follow.
You need a fuel pressure gauge to determine if the front tank isn't putting out enough pressure. If it's full of nasty old gas, I'd drain it first, fill it with fresh gas, and then buy a new fuel filter & install it.
Then use the pressure gauge to see if you have a weak pump. If it's weak, it's got to come out. I had one weak pump in an old truck of mine and I pulled the bed off and replaced both tanks. It worked great right up until the truck got wrecked less than a year later.
It also sounds like you have the idle problem identified. The first thing I'd do is put a new TPS on it.
rick - you'd be better off starting a new thread for your problems. When two users start talking about two similar problems in one thread, it gets very hard to follow.
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Yeah I kinda figured it was the pump, but hey you cant blame a guy for wishfull thinking. I have located some great deals on some pumps on EBAY but I dont know which part numbers I need. Where can I cross referance these or find some pictures of the front pump.
As for the TPS I had to get a tag for the truck today and didnt get to the parts store but when I change it I will post the results.
Also, is it easier to pull the bed ( I have the means to lift it) or drop the tank ( granted it is FULL of gas)??
As for the TPS I had to get a tag for the truck today and didnt get to the parts store but when I change it I will post the results.
Also, is it easier to pull the bed ( I have the means to lift it) or drop the tank ( granted it is FULL of gas)??
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Post Fiend
Joined: Mar 2002
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From: Bonita Springs FL
Not sure on a part number, but you could go to rockauto.com and look it up on their website. Or you could just order it from them - the stuff they sell is far better quality than anything you can get in a local parts store.
I just replaced the TPS on my girlfriend's Bronco this weekend - I used motorcraft parts that I got from rockauto.com.
I just replaced the TPS on my girlfriend's Bronco this weekend - I used motorcraft parts that I got from rockauto.com.
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Thanks guys, I may just go ahead and do a major tune up and fluid change. I noticed that under hard accelleration the truck has a miss, probably needs some plugs and wires. This may sound stupid, but do you think I chould just go ahead and change both pumps while I have the bed off the truck? I dont think the rear pump is faulty the truck has no problem accellerating ( other than the occassional miss) but the fuel gauge is very active. I can go 10 miles and it may drop 1/4, turn off the truck and turn it back on, its back to full or less than 1/2 its CRAZY. So I just keep it full which is an act of congress on a ford truck, it takes forever to pump the last 3 or 4 gallons.
Any way thanks for the help
Any way thanks for the help
Tuned
Joined: Mar 2003
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From: austin
For the TPS, I would follow the Haynes procedure to see if it is definitely bad. Just get your trusty voltmeter out, with key on engine off check voltage on wires at idle and at WOT. Haynes has the correct voltages that it should be. This will tell you if you definitely need to replace the TPS (since auto stores won't take electrical parts back unless they are defective).
As for the fuel tank question, it sort of depends on your situation. If you're definitely going to pull the bed to do one tank, and you have $100 laying around for the 2nd pump, then go for it. I would wait since it's an expensive part and there is nothing wrong with your rear tank's pump.
For the fluctuation in the fuel gauge, I've seen some posts indicating it's the sending unit. Mine does the same thing - front tank reading is wacky after a few gallons are used, back tank is fine all the way to Empty. Try searching for sending unit issues on here.
-Chris
As for the fuel tank question, it sort of depends on your situation. If you're definitely going to pull the bed to do one tank, and you have $100 laying around for the 2nd pump, then go for it. I would wait since it's an expensive part and there is nothing wrong with your rear tank's pump.
For the fluctuation in the fuel gauge, I've seen some posts indicating it's the sending unit. Mine does the same thing - front tank reading is wacky after a few gallons are used, back tank is fine all the way to Empty. Try searching for sending unit issues on here.
-Chris
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From: Bonita Springs FL
Originally Posted by bmazingo
This may sound stupid, but do you think I chould just go ahead and change both pumps while I have the bed off the truck?
I figured as long as I had it open, might as well do both. It was another, I think $150 for the second pump. They're NOT cheap, but the work required to get to them suggests to me that it's cheaper and easier to do it while it's open.You'd also need a new sender for that tank, and I would inspect ALL the wiring carefully while you have it apart. The gauge issue could be up to and including the dash switch.