Do in-tank fuel pumps give any warning of impending failure/

I really doubt that...
It would depend on the pump design
I think the tank would have to be dropped, the pump removed and a filter screen installed on the pickup tube
Then you would never have to worry about it again
The external would be an easy replacement

NO. External pump will NOT draw fuel through a failed Ford Internal High Pressure Pump. I spell that out because you can draw fuel through the older low pressure pumps used with carburetors. But if it's a High Pressure, it at least has to be spinning, even if only struggling, to not serve as a shutoff down in the tank.

I'm told most fuel pumps PUSH fuel better than they PULL it. That's part of why they're in-tank, they're close to if not submerged in the fuel. Another part is that liquid fuel won't vapor lock. But Alas, I'm sure COST plays a major part. Expensive to repair doesn't count to the designers. Cheap to build does.

pnichols wrote:

jfkmk wrote:
pnichols wrote:

Why don't OEMs merely offer the option of dual in-tank fuel pumps - operating in parallel with each other? The chances of both letting you down at the same time are infinitely less than one letting you down.


$$$$

Ford - for instance - offers all kinds of non-standard $$$$ options for it's E350/E450 series of vans used under various commercial service applications ... dual in-tank electric fuel pumps for ultra reliability could be one of them. If available for motorhomes, I'd pay for dual in-tank fuel pumps in a heartbeat whenever buying a new Class B/C motorhome built on one of Ford's van chassis.

P.S. #1: I would have paid extra $$$$ for a limited slip differential and dual alternators, too, if Winnebago/Ford had offered the combination when we bought our new E450 based Itasca motorhome.

P.S. #2: I would have paid extra $$$$ for the good old easy to access individual/separate engine equipment drive belts instead of a hard to get at and snake around pulleys single serpentine belt, too ... so that if a belt broke you would only be partially disabled instead of completely disabled like you are with a busted serpentine belt.

At issue is you have two pumps working at the same time wearing out at the same rate. Your second pump might not fail at the same exact time but it would be close. You'd be better off cost wise replacing the pump at a given mileage interval. Besides, it would cost s fortune for the manufacturers to make the option available for the very few that would opt for it.

And yes, I do remember the bad old days with all separate belts. It was a pain adjusting the tension on multiple belts. The one that broke was always the one on the inside requiring the removal of all belts. They'd last about 30k before you have to replace them. The newer serpentine belts will go 150k plus miles and require releasing the tension at one point. It took me less than 5 minutes to replace it on my SUV and that was from opening the hood to closing it. Bam, done for 150k or 5 years.

I've had to replace the in tank fuel pump in both the 92 Suburban and 98 Yukon. The Suburban failed at home with a quarter tank of fuel. The Yukon failed at store, banged the tank on bottom and pump started running, drove it home and replaced it at home. Yukon was harder because tank was near full and it was hard to remove the fuel lines (special connector, made a tool).

If you have failure, try banging on the tank, you may get it running long enough to make it somewhere where the pump is easier to change (like home in garage).

The in tank pump would not be a problem to change if an access port would be built in. A few cars have a "door" where you remove the rear seat and there is the access point. Trucks could have a similar access point in the bed.
The problem would be the "door" would add cost and the cost would be passed to the consumer and a lot of consumers simply do not care about ease of maintenance because they do not service their own equipment.

Halmfamily wrote:
The mechanic said to not overfill the fuel tank, stop filling when it the pumps shuts off. Don't know of that had anything to do with the failure or the fact the van was a POS.

The reason for this is that overfilling can cause fuel to get into the evap vent lines and saturate the charcoal canister which in turn can cause emissions issues and check engine lights. Really nothing to do with the fuel pump.

Wiz, I don't know that you could take a fuel pump and mount it externally, it relies on fuel to keep it cool. Also any leaks/vapors are contained in the tank. An external pump would have to be engineered to withstand the heat and 100% duty cycles, so would likely cost a lot more for the OEM.

The 98 and 01 Grand Prixs I got for the kids both have access hatches in the trunk floor behind the back seat. I suspect other GM W bodies are the same. Pull the back seat out and you can work on the pump easily from inside the car.

It would be nice if you had a dash light for low fuel pressure or some indication that the pump was going south...the big issue with these pumps is not dropping the tank to change them, it's the "worked fine right up until it didn't" issue, where these things can quit with no warning regardless of where you happen to be.

I changed my fuel filter every year since new and mine still quit at 101k. I was in the middle of an intersection waiting to make a left turn, sitting there with my foot on the brake waiting for oncoming traffic to clear (not towing at the time.) When traffic was clear, I hit the gas and the engine died. Cop had to help me push the truck out of the intersection, it was blocking traffic (these 2500's are heavy!). Flatbed to the shop with diagnosis bad fuel pump.

BurbMan wrote:

Halmfamily wrote:
The mechanic said to not overfill the fuel tank, stop filling when it the pumps shuts off. Don't know of that had anything to do with the failure or the fact the van was a POS.

The reason for this is that overfilling can cause fuel to get into the evap vent lines and saturate the charcoal canister which in turn can cause emissions issues and check engine lights. Really nothing to do with the fuel pump.

Wiz, I don't know that you could take a fuel pump and mount it externally, it relies on fuel to keep it cool. Also any leaks/vapors are contained in the tank. An external pump would have to be engineered to withstand the heat and 100% duty cycles, so would likely cost a lot more for the OEM.

The 98 and 01 Grand Prixs I got for the kids both have access hatches in the trunk floor behind the back seat. I suspect other GM W bodies are the same. Pull the back seat out and you can work on the pump easily from inside the car.

It would be nice if you had a dash light for low fuel pressure or some indication that the pump was going south...the big issue with these pumps is not dropping the tank to change them, it's the "worked fine right up until it didn't" issue, where these things can quit with no warning regardless of where you happen to be.

I changed my fuel filter every year since new and mine still quit at 101k. I was in the middle of an intersection waiting to make a left turn, sitting there with my foot on the brake waiting for oncoming traffic to clear (not towing at the time.) When traffic was clear, I hit the gas and the engine died. Cop had to help me push the truck out of the intersection, it was blocking traffic (these 2500's are heavy!). Flatbed to the shop with diagnosis bad fuel pump.

Man, that would sure be nice if they all had access holes from inside the trunk! Another reason for not being mounted outside the tank (I think it may have been mentioned) is the pumps for injected engines put out high pressure but have poor suction. They need to be mounted in the liquid they're pumping.

My Blazer pump died just like your burb's. The only difference is I was able to start it long enough to make it through the intersection. No fun nonetheless.

jfkmk wrote:
At issue is you have two pumps working at the same time wearing out at the same rate. Your second pump might not fail at the same exact time but it would be close. You'd be better off cost wise replacing the pump at a given mileage interval.

Two wearing out "at the same time" is not going to happen. Take a quick study of the probability statistics concerned with the failure of electro-mechanical devices and it'll show you that: The probability of one electro-mechanical item failing - mulitplied times the probability of another identical electro-mechanical item failing while in service along with the other - equals the resultant probability one must live with of both "going bad at the same time". These two probabilities multiplied together make for a very, very, very small probability of paralleled in-tank fuel pumps ever failing at the same time and leaving one stranded in a busy intersection or out in the middle of nowhere. Of course along with parallel in-tank fuel pumps one should have some kind of indicator on the dash telling when the first one to fail has, indeed, failed -> hence you're now relying on only one of the two in-tank fuel pumps and bettter do something about it.

jfkmk wrote:
The newer serpentine belts will go 150k plus miles and require releasing the tension at one point. It took me less than 5 minutes to replace it on my SUV and that was from opening the hood to closing it.

This seems to NOT be the case for the V10 engine in the common Ford E350 and E450 cutaway van chassis under a lot of Class B/C motorhomes. The mechanic that last changed mine in our rig (per my request at 45K miles for preventative maintenace) needed a special tool to do it (I think it had something to do with holding back, and/or maybe completely removing, the tensioner pulley to install a new belt). Plus ... I looked quite some time under our motorhome's van nose hood on our E450 and it's packed in there. I could not get near it's serpentine belt without removing the radiator shroud and then probably having to lay on the ground underneath the engine to snake a new belt up and around all the bottom sides of the various pulleys. I wouldn't want to have to do this out in the desert somewhere. Nevertheless, I carry a new spare serpentine belt anyway, just is case I can figure out how to replace a broken one should I have no choice - since one is entirely dead in the water when a serpentine belt breaks. At least with the old multiple belt design if, say, the alternator belt broke ... I could keep on driving with no alternator ... since some motorhomes can go a long distance running off the engine battery in conjunction with the coach battery(ies) powering all the engine functions (like ours can using the emergency boost switch).

By the way, a fuel pump tank access port will not be of any help in getting to the fuel pump in a motorhome ... unless the motorhome builder installed an in-floor access port directly above the tank access port.

pnichols wrote:

jfkmk wrote:
At issue is you have two pumps working at the same time wearing out at the same rate. Your second pump might not fail at the same exact time but it would be close. You'd be better off cost wise replacing the pump at a given mileage interval.

Two wearing out "at the same time" is not going to happen. Take a quick study of the probability statistics concerned with the failure of electro-mechanical devices and it'll show you that: The probability of one electro-mechanical item failing - mulitplied times the probability of another identical electro-mechanical item failing while in service along with the other - equals the resultant probability one must live with of both "going bad at the same time". These two probabilities multiplied together make for a very, very, very small probability of paralleled in-tank fuel pumps ever failing at the same time and leaving one stranded in a busy intersection or out in the middle of nowhere. Of course along with parallel in-tank fuel pumps one should have some kind of indicator on the dash telling when the first one to fail has, indeed, failed -> hence you're now relying on only one of the two in-tank fuel pumps and bettter do something about it.

jfkmk wrote:
The newer serpentine belts will go 150k plus miles and require releasing the tension at one point. It took me less than 5 minutes to replace it on my SUV and that was from opening the hood to closing it.

This seems to NOT be the case for the V10 engine in the common Ford E350 and E450 cutaway van chassis under a lot of Class B/C motorhomes. The mechanic that last changed mine in our rig (per my request at 45K miles for preventative maintenace) needed a special tool to do it (I think it had something to do with holding back, and/or maybe completely removing, the tensioner pulley to install a new belt). Plus ... I looked quite some time under our motorhome's van nose hood on our E450 and it's packed in there. I could not get near it's serpentine belt without removing the radiator shroud and then probably having to lay on the ground underneath the engine to snake a new belt up and around all the bottom sides of the various pulleys. I wouldn't want to have to do this out in the desert somewhere. Nevertheless, I carry a new spare serpentine belt anyway, just is case I can figure out how to replace a broken one should I have no choice - since one is entirely dead in the water when a serpentine belt breaks. At least with the old multiple belt design if, say, the alternator belt broke ... I could keep on driving with no alternator ... since some motorhomes can go a long distance running off the engine battery in conjunction with the coach battery(ies) powering all the engine functions (like ours can using the emergency boost switch).

By the way, a fuel pump tank access port will not be of any help in getting to the fuel pump in a motorhome ... unless the motorhome builder installed an in-floor access port directly above the tank access port.

Right. I never said both pumps would fail at the same time. I know all about probability and how it applies to risk (in this case the risk of both pumps going at the same time) and know it's practically impossible. My point is, if there wa s a spared pump in the tank, and it was running all the time the vehicle was running just like the primary pump, it would reach its end of life expectancy at the same time as the first pump. They wouldn't fail at the same time, but would be ready to. Even in industries where a pump is critical enough to have a secondary pump, the secondary pump would not be running all the time the primary pump is, "just in case". It would be switched over if the primary pump fails.

In the case of a vehicle, I go back to it would cost the manufacturers a fortune to provide the option of a second fuel pump. The cost would have to be passed along to the buyer. Most drivers can't check the air in their tires, do you think a spare fuel pump would mean anything to them? Probably so few would opt for this that. The relatively few who would want to would say forget it, I'll just change the pump out at 100k miles and save money.

A serpentine belt is infinitely easier to change than the multi belt set up and the belt is far superior, at least in my experience. If you had to remove the radiator etc to get to ONE belt, could you imagine trying to get to 3 or 4? The beauty of the serpentine belt is it takes up far less depth than the multi belt setup did. I have one of those "special tools" for replacing the serpentine belts. It's basically a long flat wrench to get to the tensioner and costs next to nothing.

I fully understand that when a chassis is built bu one manufacturer and sold to another to have the body they can't put an access port for the fuel pump, I just thought it was pretty cool that GM had thought about it for the Grand Prix that Burbman spoke of.

Two pumps.... at what point do you replace both? Or do you always just replace the failed unit?

One pump.... I am thinking it might be less money and hassle to just replace the pump at about 10 years or 120,000 miles.