1999 b4000 on my 5th fuel pump!!! Haha

skeeterskeet01 · Mar 19, 2017

Hey, I'm new to this forum and to any kind of info like this on the Internet so thanks for letting me join. This "taptalk" deal is taking some serious getting use to!

The reason I am here is, I have a 99b4000. I replaced the fuel pump in it 5 friggen times! I dropped the tank the first time, cleaned er out, paper toweled er right out, changed the filter sock, fuel filter, pump and checked to make sure the bypass regulator in the tank was doing its job and bypassing at 70-80 psi. Then I pulled the shrator valve and blew clean compressed at through the system, put fresh gas in er mixed 50 to 1 with 2 stroke gas cuz that's the jerry can I had laying around (mixed gas is good for them things anyway)... I also made its own body ground and frame ground to the ground on the fuel pump wiring harness.... after all of that she is still eating through fuel pumps like a fat chick goes through cake! Any of you mindful lady's n gents know what the boggle is here? Cuz if ya do I would love to hear it!

Thanks again! And thanks for letting me join!

Sent from my SM-G900W8 using Tapatalk

Mark_88 · Mar 19, 2017

Hi and welcome to TRS~!

I had a similar issue with my Tempo that spanned five years and then suddenly cleared up. Replaced it five times too...and when I called Ford to complain because it was replaced every time under warranty they said they didn't understand it and offered to cover some other work after the warranty expired.

In your case I would have to ask if you know what brand of pump you are putting in because I'd heard there were issues with one particular brand. I can't remember off hand what the name was though...but if you know that might be a clue to why they all failed...if they were all by the same manufacturer.

RonD · Mar 19, 2017

Well 3rd party fuel pumps are known to not last very long but in your case it seems more like a vehicle issue.

You will need a Volt Meter
Start engine and test battery voltage, should be under 15volts, over 15 means bad alternator/voltage regulator

In passenger footwell(cab) there will be an Inertia switch, small black box with red button on the top, 3 wires.
Might be under glove box or upper kick panel
This switch sends the 12volts for the fuel pump from fuel pump relay(engine fuse box) to the fuel pump.
Purpose of the switch is to cut fuel pump power if there is a sudden stop(accident) or roll over, there is a metal ball inside that holds switch closed.
Red button on the top is to reset it temporarily, it must be replaced if ever tripped.

But the point of explaining what and where it is, is so you can hook up a volt meter to it.
And you can WATCH this volt meter while driving.
You are looking for lower voltage and of course voltage spikes.

With key on you will see 12volts for 2 seconds, then 5 to 7 volts(computer's monitor voltage) until engine starts, then you will see under 15volts, 14.4 to 14.9 for about 5 minutes of driving.
Then voltage will start to drop to 13.5-13.8volts, which is correct voltage it should stay at until engine is restarted.
Voltage can vary with RPM but should return to 13.5-13.8.
So if you are driving on the highway at 2,500 RPM the steady voltage should be the same as when sitting at a stop light, 800RPM
That's the voltage regulators job, maintaining correct voltage regardless of RPM or Load(lights and heater fan).

After startup the battery is drained, so voltage regulator does a "Quick Charge", 14.4-14.9volts
This higher voltage will burn out a battery if used long term, so after quick charge voltage regulator lowers the voltage to 13.5-13.8volts, this keeps battery charged but won't burn it out.

If your voltage is dropping and spiking the fuel pump motor will have a short life

When you pulled out the previous motors were they all "dead", did you try an OHM meter test on them, or just hook one up to 12volts and ground to test it?

skeeterskeet01 · Mar 19, 2017

RonD said:
Well 3rd party fuel pumps are known to not last very long but in your case it seems more like a vehicle issue.

You will need a Volt Meter
Start engine and test battery voltage, should be under 15volts, over 15 means bad alternator/voltage regulator

In passenger footwell(cab) there will be an Inertia switch, small black box with red button on the top, 3 wires.
Might be under glove box or upper kick panel
This switch sends the 12volts for the fuel pump from fuel pump relay(engine fuse box) to the fuel pump.
Purpose of the switch is to cut fuel pump power if there is a sudden stop(accident) or roll over, there is a metal ball inside that holds switch closed.
Red button on the top is to reset it temporarily, it must be replaced if ever tripped.

But the point of explaining what and where it is, is so you can hook up a volt meter to it.
And you can WATCH this volt meter while driving.
You are looking for lower voltage and of course voltage spikes.

With key on you will see 12volts for 2 seconds, then 5 to 7 volts(computer's monitor voltage) until engine starts, then you will see under 15volts, 14.4 to 14.9 for about 5 minutes of driving.
Then voltage will start to drop to 13.5-13.8volts, which is correct voltage it should stay at until engine is restarted.
Voltage can vary with RPM but should return to 13.5-13.8.
So if you are driving on the highway at 2,500 RPM the steady voltage should be the same as when sitting at a stop light, 800RPM
That's the voltage regulators job, maintaining correct voltage regardless of RPM or Load(lights and heater fan).

After startup the battery is drained, so voltage regulator does a "Quick Charge", 14.4-14.9volts
This higher voltage will burn out a battery if used long term, so after quick charge voltage regulator lowers the voltage to 13.5-13.8volts, this keeps battery charged but won't burn it out.

If your voltage is dropping and spiking the fuel pump motor will have a short life

When you pulled out the previous motors were they all "dead", did you try an OHM meter test on them, or just hook one up to 12volts and ground to test it?

The pumps never completely died... they would just stop making the right amount of pressure. (0-45 psi).

I have a live data plug in for my truck and she doesn't charge over 14.4 under high load conditions, and for the he'll of it, I even swapped out the alternator cuz I found a near mint one at the wreckers along with the whole fuel tank sender including the pump and fuel regulator.

I have not "ohmd" out any of the pumps out yet, but I did bench test them with a fuel pressure gauge and another sending unit. I tested all the pumps that got weak and even tested the pumps before installing them in the truck to male sure the bypassed between 70-80 psi, which they did with both in tank regulators.

You guys are great! Thanks for taking to time to give a crap about my old huntin truck!

Sent from my SM-G900W8 using Tapatalk

Shran · Mar 20, 2017

I am gonna guess that poor quality aftermarket parts contribute heavily to this.

When I bought my '86 in 2008 it needed fuel pumps - both of them. I replaced them with "high quality" NAPA pumps. The high pressure one lasted till 2015, not bad. However I have replaced the in-tank pump AT LEAST once a year, that is like 9 or 10 pumps now and I carry a new spare at all times. I have tried literally every brand out there, none last more than a year or so. I have resorted to having two on hand, one from NAPA and one from AutoZone that both have lifetime warranty and swap them out as needed.

I don't know what causes this to happen other than just poor quality pumps. The impeller just quits and the pump locks up. Ironically the best one I have had so far is in my '88, got it on closeout complete with sending unit from Rock Auto for $16. It's going on over 2 years now.

RonD · Mar 20, 2017

3rd part fuel pumps have 1 to 2 years warranties

Motorcraft fuel pump, 60day warranty, lol

My 1994 Ranger factory fuel pump is on its 23rd year, knock on wood, 400k

Mark_88 · Mar 20, 2017

I think it has to do with the diaphragm in them...that's what one tech told me years ago but I don't even know if they have diaphragms...

I would be inclined to try to figure out a way to have them outside the tank if I had to replace them so often...I know the fuel helps to cool the pump and may be a limiting factor as to where it can go...but I'm sure someone must make a high pressure pump that can be cooled otherwise...I've just never bothered to investigate it.

http://www.ebay.com/itm/300LPH-Universal-External-Inline-Fuel-Pump-Replaces-BOSCH-0580254044-044-/331277337290

I found this one that only produces 45 psi so maybe put two of them together for 90psi...

pjtoledo · Mar 20, 2017

did you ever dissemble the failing pumps to see what went wrong?

Shran · Mar 20, 2017

Mark_88 said:
I would be inclined to try to figure out a way to have them outside the tank if I had to replace them so often...I know the fuel helps to cool the pump and may be a limiting factor as to where it can go...but I'm sure someone must make a high pressure pump that can be cooled otherwise...I've just never bothered to investigate it.

They do make such a pump, it's the one attached to the frame rail of '86 up Ford pickups :derisive:

That style of pump is used extensively in other applications, for example in a setup that includes a fuel cell with bottom supply ports that gravity feeds into said pump. Those rarely fail in my experience.

^ that is also going to be the ultimate fix for my problems, by the way. I suspect that in addition to poor quality pumps, crappy strainers are also a contributing factor. Every time I remove a bad pump it has at least a little bit of debris inside the strainer and in the impeller area. They are designed to fail. Fortunately my flatbed gives me miles of room to remove the sending unit with the tank in place... it's about a 10 minute job, hence why I haven't put much effort into re-engineering the fuel system.

Mark_88 · Mar 20, 2017

Shran said:
They do make such a pump, it's the one attached to the frame rail of '86 up Ford pickups That style of pump is used extensively in other applications, for example in a setup that includes a fuel cell with bottom supply ports that gravity feeds into said pump. Those rarely fail in my experience.

^ that is also going to be the ultimate fix for my problems, by the way. I suspect that in addition to poor quality pumps, crappy strainers are also a contributing factor. Every time I remove a bad pump it has at least a little bit of debris inside the strainer and in the impeller area. They are designed to fail. Fortunately my flatbed gives me miles of room to remove the sending unit with the tank in place... it's about a 10 minute job, hence why I haven't put much effort into re-engineering the fuel system.

Cool! Good to know someone is thinking outside the tank...lol

I knew they were available but wasn't sure if they made anything stronger than the 45 psi or so that they need up to 1997.

The 1999 in question needs the 65 psi so if they have one that will work in that application it might help the OP move away from the in tanks...and I'm sure many people would love to see your solution in a write up if it works out for you. :icon_thumby:

1999 b4000 on my 5th fuel pump!!! Haha

skeeterskeet01

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Mark_88

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RonD

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skeeterskeet01

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Shran

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