Why have auto manuf. eliminated fuel filters?

[HerrStig]

For those worried about safety, the new ECU controlled fuel pump motors are "brushless DC designs, which don't have any sparking brushes. Yes, electric current and gas don't mix well, but there
has been current flow in fuel tank senders for as long as there have been "electric" fuel gauges.

 

[HerrStig]

The old VW bugs with a single tiny carb had no filter. Standard "aftermarket" practice was to cut the line between the fuel pump and carb and insert a Fram GF 1 (as I recall). The idle jet was the one which often clogged back then, as well as the accelerator pump nozzle. Cuttting open the used filter usually produced some junk inside. I remember when a couple of oil companies started putting big PH 1 style filters right at the gas pump to hose connection. Now, apparently, "all is good". FAA rules regarding the use of "auto fuel" in private aircraft have been relaxed a bit.

 

[lexus114]

Originally Posted By: HerrStig
Originally Posted By: lexus114
Originally Posted By: Hokiefyd
Originally Posted By: morris
i dont under stand. gasoline catches on fire, soooo lets put electricity in the gasoline.


Gasoline doesn't catch on fire. Gasoline VAPOR burns.

Throwing a match into a gallon of gasoline (especially cold gasoline on a cool day) is like throwing a match into a gallon of water.



I dont know about that one.
No VAPOR, no BOOM.



Okay, but you go first. I`ll be right behind ya.

 

[cchase]

Originally Posted By: HerrStig
Originally Posted By: cchase
Originally Posted By: HerrStig
Returnless systems put a much smaller volume through the system. The Toyota blogs long ago suggested not touching the in line filter used on returnless systems unless a check engine code pointed that way. I've got almost 300K on the OEM filter in a Camry.


It doesn't matter whether the system is returnless or not, the same amount of fuel ends up being passed through the filter. Using the same filter on the same fuel hundreds of times does not load up the filter more quickly.


You don't understand how a shunt regulated system works, then. Anything in that type of system that is NOT burned gets send back to the tank and, obviously, pumped through the filter again. The non-return system does NOT do that. Some pretty clever fuel pump control technology is used as part of the pressure control system. The ECU controls fuel pump speed based on actual demand. You COULD Google it.


I understand just fine how fuel delivery systems work. The point is that if 10 gallons of fuel has 1 oz of particles within the size limits of the filter, it doesn't matter whether the 10 gallons goes through the filter 1000 times or 1 time, 1 oz of particles will be captured by the filter. Passing the same fuel through the same filter doesn't magically capture ever more particles.

 

[mechtech2]

Originally Posted By: morris
i dont under stand. gasoline catches on fire, soooo lets put electricity in the gasoline. so who thought of that? fire men, parts makers, hospitals, doctors, lawyers, Judges, insurance cos, mechanics, car makers. the car makers are like the government, they give you what THEY want you to have, what you want does not come into any thing.


This always gave me reason to think about this aspect.
But it is submersed, and no air is present. Fire/explosion needs O2. And a fuse/relay protects from overheating the pump.

Plugged filters are rare compared to a few decades ago.

 

[Jim Spahr]

aisiancivicmaniac, those were two good photo's you posted. But you didn't say what the 1./ fuel pump and 2./ the fuel filter came out of, ie, year, make, and model of vehicle. I didn't see how the fuel filter attached to the fuel pump pick up. It did look like the fluid in the fuel filter was very black. I don't think the new sock on the fuel pump pick up is a nice heavy duty filter like the one shown. They are a fabric sock strainer.

 

[punisher]

I think OEMS figured that the new pumps have to move a lot less fuel in a returnless system, likely 100-1000 times less than older systems that had a fuel return. You don't need a huge fuel filter inline, and it makes more sense to filter the fuel well before it can thrash/cause wear on the OEM pump.

Just an opinion, I could be wrong.

 

[Samilcar]

Originally Posted By: punisher

the new pumps have to move a lot less fuel in a returnless system, likely 100-1000 times less than older systems that had a fuel return


A filter in a return system sees a lot more fuel flowing through it, but it's exposed to the exact same dirt load as a filter in a returnless system. Once fuel has been through the filter once, any filterable debris should be removed from the fuel. If that cleaned fuel then goes back through the filter again, it should contain no filterable debris.

 

[MNgopher]

There are two significant issues with the theory above. One, it assumes that all the debris goes through the filter on the first time through, and two, that the fuel that goes through the filter magically stays clean upon return to the tank that held the debris to begin with.

Reality is on a bypass system, the volume of flow gives the same fuel multiple opportunities to deliver debris to the filter. A returnless system only gives one opportunity.

I'll grant the total material delivered to the tank is the same. The number of chances it has to be picked up is substantially less though.

 

[mechanicx]

As was mentioned by others, on a returnless system the regulator is usually mounted downstrean or before the in-tank fuel filter so it see less fuel flowing through than a return type system. That and the bigger fuel filter in the tank makes for a longer service life.

Although, they could've still used an external in-line fuel filter with a returnless system with a bypass hose connected to the inlet side of the in-line filter. The first returnless filters were like this. I prefer that to mounting the filter in the tank as it's easier to change.

 

[PandaBear]

I don't think return-less have anything to do with fuel filter load. The fuel usage will still be the same (more or less assuming the fuel pump doesn't use a lot of energy), and filtered fuel will have less stuff to be filtered again in loop.

Making the filter bigger would be the reason of extended interval IMO, as well as adjusting fuel pressure to compensate the filter load.

 

[mechanicx]

Well the regulator being before and bypassing the filter on returnless system means the less fuel is pumped through the filter even if the same amount is pumped to the regulator and the same is injected in the engine. Also some returnless fuel pumps are PWM and the fuel pump reduces pumped volume to keep pressure constant. But whether the fuel regualtor bypasses before or aftewr the filter it probably doesn;t make a huge difference in filter loading.

 

[Samilcar]

Originally Posted By: MNgopher

Reality is on a bypass system, the volume of flow gives the same fuel multiple opportunities to deliver debris to the filter. A returnless system only gives one opportunity.


Which, to me, is even more of an argument in favor of a serviceable fuel filter. If the debris load is the same, but less of that debris is caught in the returnless system, where does the unfiltered debris go? Straight to the fuel injectors.

 

[cchase]

Originally Posted By: Samilcar
Originally Posted By: MNgopher

Reality is on a bypass system, the volume of flow gives the same fuel multiple opportunities to deliver debris to the filter. A returnless system only gives one opportunity.


Which, to me, is even more of an argument in favor of a serviceable fuel filter. If the debris load is the same, but less of that debris is caught in the returnless system, where does the unfiltered debris go? Straight to the fuel injectors.


A case in point where I think the whole mentality here is flawed.

 

[MNgopher]

Where does the unfiltered debris go? Nowhere - it stays in the tank.

If fuel gets to the injectors, its been filtered.

 

[surfstar]

Bottom line - its a conspiracy. Vehicles will be dropping dead on the side of the road any day now from clogged fuel filters.


That's what I get for one side of the argument anyways.

 

[Kruse]

Originally Posted By: Jim Spahr
Why have Chrysler and GM stopped installing fuel filters on their cars? The only 'filter' is the sock on the fuel pump pick up in the fuel tank! Are they saying the fuel is so clean, that the fuel filters are no longer needed? I know fuel injector nozzles are very sensitive to bad fuel. This seems to be a cost reduction move only.


About a year ago, I bought a '95 Mustang with a blown engine. (Previous owner's neglect did it in) Anyway, when I rebuilt the engine and was ready to fire it up for the first time, I checked the fuel filter and it had the original fuel filter on it. The filter was so bad that it had actually rusted through and was spraying gas out of it. People today don't maintain their cars on their own free will, they just wait for the car itself to tell them what needs to be done. (Oil service reminders and OnStar comes to mind here)
Perhaps the manufacturers are doing away with the owner-replaceable fuel filter because it's just another neglected item that will eventually leave the driver sitting along side of the road when the filter internally rusts out and the filter element and the rust eventually clog up the injectors.
I do know that when I first ordered a fuel filter for my '99 Suzuki Swift, several parts men told me that they couldn't get it. I first thought they couldn't get it because it was a Suzuki, but a parts man eventually told me that the fuel filter was inside the gas tank. This particular make and model does have a fuel return line.

 

[ltslimjim]

For me, a good question for those still using replaceable filters is this:

Do you need to use an OE fuel filter or can an aftermarket suffice much like aftermarket oil filters?

 

[Samilcar]

Originally Posted By: MNgopher
Where does the unfiltered debris go? Nowhere - it stays in the tank.

If fuel gets to the injectors, its been filtered.



This prior quote of yours: "I'll grant the total material delivered to the tank is the same. The number of chances it has to be picked up is substantially less though" ...appears to be saying the complete opposite.

If your contention is that A. the total debris load is the same, and B. the chances of that debris load being picked up by the filter in a returnless system is LESS... then that debris that's not picked up by the returnless filter has to go SOMEWHERE. This debris is not left in the tank, because after it has passed through the filter, it only has one place to go. It can't return back to the fuel tank (hence the name "returnless").

 

[MNgopher]

The debris not picked up by the filter remains in the tank. You seem to assume the 100% of the debris delivered to the tank is put through the fuel filter on its first run (or only run in a returnless system). It isn't.

Don't confuse the debris delivered to the tank with the debris delivered to the fuel filter. Ever wonder why there is junk in the bottom of a gas tank? Not all of just came from that last batch of gas you bought. Its never been picked up and run through the fuel filter.