Fuel Filter Question

[56Nomad]

Going over past postings, some are changing them out
every 10,000....... others let them go over 20,000
Obviously, it depends on where you purchase your diesel
fuel and the quaility of the fuel.

What are the down sides of leaving the fuel filter on
until diminished engine performance becomes evident?
Is there any possible engine damage could be done by
not replacing the fuel filter in a timely manner?

I carry an extra fuel filter and strap wrench in the truck
at all times, so I'm prepared if there are problems.
But my question is, if it ain't broke, why fix it yet?

(Oh, I do change my oil & oil filter EVERY 4000 miles)

Thanks

[More Power]

I changed our fuel filter at ~22,000 miles. I purposely ran it that far because I wanted to see what effect it had on the engine to run the fuel filter that long.

At 22,000 miles, I noticed some "fishbite" and periodic jerkiness while traveling down the highway on cruise. These symptoms became more pronounced while towing, and whenever more power was used (like passing). These are classic symptoms of a fuel supply problem, with a dirty fuel filter being the most likely candidate.

Changing the fuel filter eliminated the above symptoms.

MP

[SoCalDMAX]

56Nomad,

I think the ECM monitors fuel rail pressure, and if the fuel filter is clogged, it will manifest itself as low fuel rail pressure. At this point, I imagine the fuel pump is struggling like crazy to pull fuel, against quite a bit of restriction. This can't be good for it's longevity; no pump works well in suction mode and they really don't like to pull a big vacuum.

The dangerous part is at a certain point, the ECM goes into limp mode, and the engine won't rev over 2,000 rpm and the TC unlocks and tranny stays in 3rd gear. This can be pretty dangerous if on a hill (like I was) or towing on a hill (like happened to another member.) The power loss is sudden and dramatic. I would have preferred the "water in fuel" lamp to say "fuel filter" and indicate a partially clogged filter or water, long before it reached the point of limp mode.

I'm installing a vacuum/pressure sensor on the outlet of the fuel filter, and I'll post my findings on what vacuum is on a new filter vs. a nearly clogged filter. This may take a while, but my intent is to find out just how much vacuum a clogged filter causes and at what point this causes limp mode.

on edit: By the way, mine lasted just less than 12,000mi. The recommended interval is 15,000mi and I know some have gone a lot longer. It's just a matter of how clean your fuel source is.

Regards, Steve

[ 08-27-2002: Message edited by: SoCalDMAX ]</p>

[SoMnDMAX]

Here's my take... Change the filter when it's convenient for you, rather than when it's absolutely necessary out on the road somewhere. Someday the "one the road" filter change may be necessary due to a bad tank of fuel, which is unavoidable, but the filter plugging due to lack of maintenance is avoidable.

BTW, I change mine @ 10K-12K miles.

[ 08-27-2002: Message edited by: SoMnDMAX ]</p>

[MaxRock]

MP...I've read posts about "fish bite". Can you explain this symptom?

Thanks,
MaxRock

[YZF1R]

SoCalDMAX: I've also thought a fuel filter restriction gage would be useful. I had one in my Petercar. Let us know how you make out, where you tapped in for it, mounted it, etc.

Steve

[Southard]

I now have 47,200 miles with the original fuel filter. Around 90% of these miles have been while grossing anywhere from 21,000 to 29,000 pounds. I keep a filter under the seat in case I need it but I haven't yet. The engine still runs like it did when I bought it.

[Idle_Chatter]

Well, I'm now a believer!! I bought some Interceptors from Diesel Injection Service. I changed out my OEM filter at 15,000 miles and didn't look in the canister. I replaced my Interceptor Sunday before last at 30,010 miles and was just down in the garage puttering around collecting my waste oil, etc and saw the removed cartridge lying there on the drain pan and figured, "what the heck!" Well, I cut her open with a chain-type tailpipe cutter and had to take photos to post in my link below (Fuel Filter Folder)!! :eek: I poured good clean-looking green-yellow fuel out of it after removal, the parts you can see look fine, so I figured (like many of you probably have) that everything is fine. Well, the outside of the filter element can sure say different! Check out the pics! Looks like the filter was doing a really good job and I'm going to cut off the paper to take a look at the difference inside-to-outside. I sure wouldn't want to have gone another 5,000 or 10,000 miles before changing this filter! I'm on a 7,500 mile oil&filter routine now (captured a sample of my change at 30,000 and will probably send it off for analysis) and I will DEFINITELY be changing my fuel filters at every 15,000!

[SoCalDMAX]

YZF1R,

Will do, as soon as I get it installed I'll post current vacuum and update with vacuum of clogged filter.

Regards, Steve

[mdrag]

Idle Chatter,

My OEM fuel filter looked very much like yours when I changed mine at 4.6K miles. Here is a link to that post:

http://forum.62-65-dieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=002328&p=

If you click the first link in my sig, check out the Fuel/Oil filter album, the fuel filter pics are in the mid portion of that album.

[Idle_Chatter]

MaxRock, everyone seems to have missed your question on fishbite. I haven't had it, but my understanding is that it's a "stutter" in power (at high or constant rpm) that feels like a fish when it nibbles on your hook - kind of a: bap-bap-bappa-bap. Did I get that right, Juicers? I wonder if it has anything to do with pilot injection, since pilot injection has to cut-out at high rpms due to very short injection timing windows and maybe the Juice injection timing is competing with the transition from pilot-to-direct?

[SoMnDMAX]

Idle Chatter, you've got it. The "fishbite" does feel literally like a fish is nibbling at the truck. Doesn't make any noise, nor can you hear any tone change form the engine. It's just a slight jerkiness.

[MaxRock]

Thanks for the input Idle_Chatter and SoMnDMAX.

[MudNurI]

I did not change my fuel filter at 15,000 per the owner's manual, and at 22,000 miles, my truck went into limp mode.

worst condition known to man! The dealer hooked it up to the computer, and the cause was a bad fuel filter...tech said something about the "type" of fuel we use, or do we use it etc... truck is now at 38,000 miles, with no further limp mode, will wait until it happens again to change it, we've been using different fuel since 22,000 miles, little experiment we are doing. So far, no problems, and I guess we are over the "scheduled maitnence"...

Brandy

[Lone Eagle]

SoCalDMAX, Please explain how you are going to read a negative pressure ( vacuum)on the inlet side of the pump. You may read a lower inlet pressure but not a vacuum. A pressure differencial gauge on the filter is the common method. Later! Lone Eagle ;)

[FrozenAKJoe]

Thanks for the photos on the fuel filter. I always wondered why replacing this sucker so frequently was so important - now I know! I'll be sure to do mine on time.

[pullinpower]

That reminds me I have 36k on my truck and the last time I changed my fuel filter was 15k.I think its time to change,Could someone post the phone # for DIS.thanks

[SoCalDMAX]

Lone Eagle,

As I understand it, the pump is taking a suction on the fuel filter, which is at the end of 10-12' of fuel line.

Even if there's no restriction in the filter, there's going to be some vacuum just because the pump is pulling fuel so far thru the fuel line and the pump is mounted higher than the fuel tank. I think the fuel filter is quite a restriction, since it has to filter all of the fuel down to whatever size it filters. As the filter gets clogged, it's going to pose an even greater restriction, thus the vacuum between the filter and pump.

I agree, a differential pressure sensor would be far better for measuring the filter, but SPA sells a pressure sender that measures vacuum... so I'll give it a shot.

Regards, Steve

[dmaxstu]

First of all thank you Idle-chatter for the pics of the dirty filter, we can always bank on you Tom for some eye opener.
Changing the fuel filter is about the only tune-up you can give your truck.After doing that job here at home I would not ever want to do it on the road. I ended up removing the wheel well liner to complete the procedure it was easy then.
As a matter of relaying what has been hashed over here before what has been reported that you can expect problems related to a dirty fuel filter anytime after 25000 M. Stu