Fuel Filter Analysis

[Jim Brzozowski]

I've always thought if you let the OEM fuel filter get the big stuff out, the secondary filter won't clog as quickly. I ran an experiment and this week-end I will be changing out my fuel filters. The OEM has run 15,000 miles and the secondary 2 micron Racor 60S has run 30,000 miles. The engine runs perfectly, starts right away, so it seems to have worked.

If anyone wants to cut open the filters and examine them and maybe furnish some pictures of whats inside and whats found, let me know. I could ship them to you. If no one is interested, I'll probably cut them open myself, but don't have one of theose fancy filter cutters like some.

[Kennedy]

At 15k you are pushing the OE element. I'm pretty sure it will be fully discolored. My last OE element on my 2005 ran 9k. Most of this was w/o a lift pump, but the last bit was with. I can see the darkest area from where it ran w/o, but the rest of teh element is also pretty dark.

[Jim Brzozowski]

Thanks for the reply John, Yeah, I aways have pushed the limits on most everything. Not sure why? I do have another set of the same filter combinations that I planned to look at myself. Maybe I'll just do a comparison and borrow my son's new digital camera and then try and figure out how to get them on the site.

Side note: thanks for the super fast delivery of the Bilsteins. They are goooodd.

[LanduytG]

I have always changed my OE at 10K and its always been fully used and debis in the bottom. IMHO 15K is way to much.

Greg

[Jim Brzozowski]

You know my owners manual calls for fuel filter changes every 15,000 miles. I guess I'm not too worried since I have the secondary filter post OEM, but now I'm starting to think why would I think they knew what they were doing setting the 15,000 mile change intervals when the didn't try to filter the fuel below the 10 micron level? With the high pressures these FI units can generate seems that would be like media blasting the injector ends right off in a few 100,000 miles or so. Or maybe they did know and want to be sure I buy another truck much sooner than later. Marketing? Engineered Obsolence?

Thanks for the advise. Duly noted.

[mdrag]

SoTxPollock,

I agree with Kennedy and Greg, 15K is too long for the OEM fuel filter. I've been changing it at 7.5K intervals.

If you want me to inspect your filters and take a few pics, send me an email:

mdragosl-TDP at yahoo dot com

Check the links in my sig for pics of Dmax fuel and oil filters.

[madmatt]

Man did I have a good one for this post today!!! 04', 67k,,,,original fuel filter!!!! Needless to say it came in on the hook. I cut it open but have since thrown it away. It made over 20" vac just cranking. To top it all off, the mor...I mean owner was ****ed because warrenty wouldn't cover it and I charged him diag to tell him he needed a fuel filter.

[Jim Brzozowski]

67,000 miles???? Reminds me of the time I towed a guy into the nearest town. Found him stranded on the highway. Car seemed fairly new. He said it just started knocking and quit running. I asked him how many miles he had on it. He said Oh about 45,000. I asked how often do you change your oil. He looked sort of puzzled and said. Change? I've never changed the oil. Oil doesn't wear out. I just said OH, OK, Good Luck with the repair, shook my head and walked off. Yep, they are out there.

[LittleBigRig]

Guys,

I've been following the fuel filter threads for a couple of years and to be honest, I can't quite ever get what I'm looking for.

Obviously the objective here is to keep the dirt out of the system. An auxillary filter makes a huge difference, though the final particulate tests indicate that it doesn't matter whether the auxillary is pre or post.

I want to give KD credit where it is due because he aims to build the best product possible. But for me personally, I don't want the worry of having to bleed the secondary filter on the side of the road while I'm pulling the family TT to Yellowstone.

I would prefer a double-filter arrangement that allows me to service the system at reasonable intervals and in the convenience of my shop. Bleeding a filter everytime you pull in to fill up is simply not practical.

Better yet, I would prefer that the auxillary filter be on the pre side which allows the OEM priming and water management system to remain un-molested. Post OEM, I am happy that whatever water and air gets through the OEM filter system in diluted solution along with the fuel is relatively benign. After all, it is the dirt that we are all gunning for.

That being said, the one thing that nobody ever talks about what happens when a huge bubble of air is stuffed through the injectors at 25,000+ PSI when your engine "stalls" during a dual filter replacement (check all of the dual filter maintenance steps and they all say, "when the engine stalls...". Think what the heat of compressed air (pv=nrT) can do to the injectors - let alone the affects of cavitation during the transition. It seems to me that a major focus area is simply how do you maintain prime throughout the entire service activity. With 60,000 miles and 6 fuel filter changes under my belt, knock on wood, I have yet to lose prime following the OEM replacement guidelines with a single filter.

In summary, I understand and want the associated virtues of a two filter arrangement - and the first design that allows me to maintain prime when serviced will get the cash!

[fourtenposi]

Who makes the dual fuel filter setup and are you saying with this setup you have to prime your fuel system every time you fill up.

[jbplock]

Originally posted by LittleBigRig:
... how do you maintain prime throughout the entire service activity. Lift Pump ;)

My 03 has a Pre-Filter/Lift-Pump (http://community.webshots.com/album/77018086bLHHHC) followed by the OEM and a Kennedy Mega Filter (http://community.webshots.com/album/67970835fahHeh). When changing filters the lift pump (with a remote manual switch) is used to bleed the whole system through the Schrader valve service port using a modified Kent Moore Vac/Pressure gauge (http://community.webshots.com/album/73314886FLnSco). At idle the bypass regulator on the lift pump is set to yield 0 psi at the Schrader valve. All three filters are fully fluid packed with never a need to bleed between filter changes.

smile.gif

[Kennedy]

With a lift pump there are never air issues with the Mega and with my tiny bleed orifice mod there have also been zero stalls that were air related. One report that later turned out to be Edge Juice related. My lift pump control harness probvides the simplest way that I know of to bleed. I don't even use the OE hand pump any more.

The OEM system is fed a steady diet of "air" in it's stock form, of this I am sure...

[fourtenposi]

Could somebody explain what a lift pump is for and how all this stuff work? Was advantage does it serve? I gather that is allows you to run a second fuel filter. How makes the kits, I would like to read up on them furter.

thanks

[Jim Brzozowski]

Both my filters are Raccor and I have never had a bleed problem. Also, my secondary filter has the ability to trap water, of course I've never seen any, the OEM Raccor sees to that.
A lift pump is a pump that provides fuel from the tank inline through all the filter to the high pressure pump that feed the injectors. Its the best insurance that the filters will always be saturated with fuel and like JK said you wouldn't need to even use the hand pump when changing filters. I don't have one of those on this truck, but always did have on the others. Its one of those get a round to it things. Now you've got me wondering if outgassing would cause a problem running up pikes peak?? I haven't had mine above 11,000 feet so I don't know.
Mdrag, I haven't had time to even look back at cutting the filters open yet, hope things slow down a bit soon, thanks for the offer. I'll email you If I deceide to let you do that.