"Lifetime" Fuel filter dissection - With Pics

[87witmoreboost]

bad choice of words.

better as in how exactly?

What was the fuel flow with the old filter?
What was the fuel flow with the new filter.
Pressure drop with new and old?

A butt dyno does not prove anything save for what you THOUGHT has taken place.

Either give hard numbers, if you can't, that your post is nothing but an opinion and as such does not require being "PRVOED or DISPROVED as it is your opinion and nothing else.

I almost regret posting this thread as people are unnecessarily harsh on the topic. Sarcasm is always welcome and I understand people want mathematical analysis. We're not talking about a $400 part here - it's a $20 precaution and one less thing to consider if you are debugging issues with a car.

My first supra had very strange symptoms. Went in to boost and had no power after a short period of time. If I was easy on the throttle and then went WOT, it would pull for a few seconds, then lose it. If I was at a load for a while, then boosted - it didn't do much of anything. After tons of head-scratching, I figured that it couldn't maintain fuel pressure at the rail because the filter was restricting it too much. I changed the filter, problem solved. Ran as it should.

No, I didn't flow test it. Yes, I do know how. I do it at work frequently on various fluid-flow applications. Pressurize the inlet with fuel, set the timer, empty it into a bucket, weight bucket. This didn't require analysis. It was restrictive. Maybe my tank had more junk than yours.

This first experience taught me it's not worth keeping the $20 in my pocket. Put it on a lift, get sore arms from reaching up high for 45 mins to get the old one off, get the new one on and drive away with peace of mind.

Lifetime filter, my ass.

 

[Facime]

This is an interesting topic. I have been around cars for around 30 years. In that time Ive had well over 50 vehicles (this includes a jet boat, several race cars and offroad vehicles). I have travelled millions of miles in that time and most of my cars have been "fixer uppers". I often see people advise others to change their fuel filter in responce to a poor running condition. I admit even I have changed a filter in the past hoping it would lead to a miracle cure of some unknown issue. In all my years I have yet to experience a clogged filter that when replaced improved....anything.

Im not saying it CANT happen. Im saying under normal driving conditions (and even under some not so ideal conditions), its such a rare occurance that changing a fuel filter for the purpose of diagnostics/repair is near pointless.

Now, having said that, if a fuel system has been left open to the air for a long period and there is visable rust/scale in a tank, or large quantities of condensation have been pushed through the system...then MAYBE the filter is suspect, but even then a simple flow test is enough to rule it out.

Thats my .02


Edit: I think its good the topic is brought up. Healthy discussion on the topic will leave readers with food for thought in the future when researching the subject.

 

[supraguru05]

ha didnt even know these filters were supposed to last like that i replace min everything im back there doing some else such as replaceing a diff, removing thee gas tank and whatever else. i guess ive replaced it about 4 times now in about 5 years of racing. its cheap and its easy to do when im there so i just do it never thought about it being a lifetime thing. I did at one time think it was clogged but quickly found out my regulator was stuck open so the filter wasnt the problem

 

[iwannadie]

This is an interesting topic. I have been around cars for around 30 years. In that time Ive had well over 50 vehicles (this includes a jet boat, several race cars and offroad vehicles). I have travelled millions of miles in that time and most of my cars have been "fixer uppers". I often see people advise others to change their fuel filter in responce to a poor running condition. I admit even I have changed a filter in the past hoping it would lead to a miracle cure of some unknown issue. In all my years I have yet to experience a clogged filter that when replaced improved....anything.

Im not saying it CANT happen. Im saying under normal driving conditions (and even under some not so ideal conditions), its such a rare occurance that changing a fuel filter for the purpose of diagnostics/repair is near pointless.

Now, having said that, if a fuel system has been left open to the air for a long period and there is visable rust/scale in a tank, or large quantities of condensation have been pushed through the system...then MAYBE the filter is suspect, but even then a simple flow test is enough to rule it out.

Thats my .02


Edit: I think its good the topic is brought up. Healthy discussion on the topic will leave readers with food for thought in the future when researching the subject.

I think its a good topic, some people just blindly go with what they read online 'life time, dont change it Period'. I think certain situations make the 'life time' beyond reason.

I cant see pulling the gas tank and finding it coated in rust and then put the original filter back on because its 'life time'. I dont think its one of those parts you should just start replacing because something isnt running right. Test to rule it out before replacing or replace it while your in there with signs of harsh conditions.

~edit

The 2 filters pictured in this thread are I think good examples of how the filter can be good/bad. You cant look at those 2 filters and say they have seen the same conditions in their life time.

 

[figgie]

I almost regret posting this thread as people are unnecessarily harsh on the topic. Sarcasm is always welcome and I understand people want mathematical analysis. We're not talking about a $400 part here - it's a $20 precaution and one less thing to consider if you are debugging issues with a car.

has nothing to do with "harshness", "being a dick/ass/rude/crude etc".

Most of us "old timers" deal with numbers. When an "I Feel" thread comes about and more so when the thread goes on to state that it has infallible PROOF. Then you have an issue on your hands and you will be called on it.

Now you would have posted that you changed your fuel filter and it cost $20 bux. You might have gotten a why but would have saved us from having to correct you.

 

[87witmoreboost]

has nothing to do with "harshness", "being a dick/ass/rude/crude etc".

Most of us "old timers" deal with numbers. When an "I Feel" thread comes about and more so when the thread goes on to state that it has infallible PROOF. Then you have an issue on your hands and you will be called on it.

Now you would have posted that you changed your fuel filter and it cost $20 bux. You might have gotten a why but would have saved us from having to correct you.

At this point, I justified why I changed it. I've seen it make a difference in the past.

Otherwise, I hate to sound like a bitch and get this off topic. All in all, this debate is what I wanted so people can find this thread and use it to decide what is and what isn't worth doing on their own car.

 

[Poodles]

Point being, the fuel filter was hidden for a reason. More than likely it will take out the pump sock and the fuel pump before it would clog the filter.

99.9% of the time, the fuel filter is NOT the cause...

 

[MKIIINA]

At this point, I justified why I changed it. I've seen it make a difference in the past.

Otherwise, I hate to sound like a bitch and get this off topic. All in all, this debate is what I wanted so people can find this thread and use it to decide what is and what isn't worth doing on their own car.

And this was the very reason I posted that Faq over on SF in the beginning. The placement of the fuel filter is there for a reason. Here in NA we have better gas quality than in other parts of the world and as was stated earlier the gas tank is usually one of the cleanest places in a car.

If you had taken the time to read that FAQ this would have become apparent to you already and like IJ said we like debate on topics but without strong evidence it just becomes "something i saw/read on the internet"

Interesting enough I doubt those $5 replacement filters are of the same quality as the OEM ones.

 

[lintlars]

The newer Ford Focus has a non servicable air filter let me guess after 250000 its going to be just fine? dont think so same goes for a fuel filter its a small cost for peace of mind even if the factory rates these as life time unit the manufacturer could not be wrong right? the 7M is the best engine ever designed my 2 cents,opinion,belief,peace of mind, whatever,people will believe what they want to believe.

 

[Poodles]

air filter /= fuel filter

Fuel is already filtered numerous times before it even gets to your tank. Then it has to get past the sock, and then it has the fuel pump itself that would be damaged before it's even making it to the fuel filter.

 

[Satan]

I usually avoid these hot debates, but...

Filtration systems are designed for certain "ideal" conditions. That being said, I have my own doubts that this small-@$$ filter can do 10+ years, without some clogging/ (diminishing returns). Sure the interval does NOT need to be every year, but after all the $$ I've dumped into my Supras, a $20 replacement makes me FEEL better. After seeing the rust in one of the old tanks on my '90, I knew I had to replace it. I only dropped the tank after the fuel pump failed (which is when I saw why).

We all have our own peeves and ideas of what makes us feel better. If, in fact, it was designed for lifetime use, then it would NOT HAVE BEEN made into a serviceable part. Everyone's circumstances/conditions are different, so please show latitude/tolerance for each other.

I replaced my fuel pump and changing the filter was a convenient thing to do. The brown stuff that poured out of my old filter may only have been a fraction of the filtration value it had left, but for $20, it was worth the change to me (no matter what the numbers might prove).

If you're the original owner and have taken care of your baby, then you're okay. Many of the rest of us have inherited "not-so-well-kept" Supras. Changing the filter on my '91, comes out to only about $1.18 per year. I'm okay with spending that, "just to feel better." Sure I did not own it for that length of time, but I will not be changing it for another 17 years (if that), because I will maintain and KNOW what conditions the filter is subjected to from now on.

In the end, you're really only arguing about spending $20 ($5 if on sale)... I used a WIX as well and would've been even happier with only spending $5.

 

[Fozbo]

air filter /= fuel filter

Fuel is already filtered numerous times before it even gets to your tank. Then it has to get past the sock, and then it has the fuel pump itself that would be damaged before it's even making it to the fuel filter.

While this is true, keep in mind that it has had 16-22 years to accomplish this and possibly a couple hundred thousand miles.

While I agree that replacing it for no other reason might be a little out there, I still might replace it if I had the tank down for something else. I bet that the large majority of filters in people's cars would look similar to the second/cleaner one that was posted, which looks to be largely free of obstructing debris. I would not, however, trust that first one at all.

Most of the mkIII owners here are not the original owners and thus have no certain knowledge of what has happened to their supra. A tank might have been filled with sand, some weird chemical, unfiltered gas that didn't go directly from the pump to the tank, or any other foreign substance. A simple flow test will tell you if a filter is clogged or not, but without performing a more elaborate filtration test, you would have to visually inspect it for damage (i.e. a filter that is clogged and has a hole in it could flow exactly the same as a brand new filter). By the time you have it completely out and are inspecting it, why not just replace it to reassure yourself that you now know first hand exactly the condition of the filter (new).

The bottom line is that the fuel filter is a mechanical device. All mechanical devices are subject to friction and physical wear, thus it will not work 100% like it should indefinitely.

Edit: was posting this at the same time as the one above, sorry if mine sounds redundant .

 

[IJ.]

The only time a fuel filter change would be a bad thing is when the person changing it out is skill challenged or doesn't have the correct tools to perform the job properly.

I suspect a few of the recent fires have had this as a root issue.

$20 for a filter is a tiny % of what people are putting into builds but another $20 for the correct flare wrenches is priceless.

I run a pair of the Bosch filters in the engine bay where they're easy to change out at a semi regular interval, I recently opened one up after losing a pair of pumps to check for contaminents, it was clear but I saw this as cheap assurance and peace of mind.

 

[eman2289]

After reading all 4 pages of this thread, I am going to have to go with changing the filter, instead of trusting the 'lifetime' label. (Not physical label) And like many others have said, for a small amount of money, you can have peace of mind.

 

[87witmoreboost]

Did I mention I fucking love this thread?

 

[supraman7mgte]

I would replace it for the simple fact of knowing that the part is something I installed,not relying on the previous owners assurance that no one ever pissed in his tank.
Plus you get the satisfaction and joy of learning how easy it is to change!!!

 

[figgie]

Plus you get the satisfaction and joy of learning how easy it is to change!!!

2 sheared banjo bolts later. I doubt that.

speaking of filtration. Anyone have tested to see what the OEM filter, filters down to (80 micron etc).

And instead of $20 dollars. For about $180, get a real filtered system and then you can feel all warm and fuzzy for a hell of a lot longer.

I rather do the typical dual filter setup, 40 micron pre-pump and then 10 micron post pump. That will be about as clean as you can get the gasoline flowing into the fuel rails at that point.

 

[Satan]

Below is the info I had added to the Fuel Filter FAQ deal on SF... Hope it helps. The only additional thing I'd add is that you should spray some PB Blaster/WD40 in key places, prior to removing. I know that this is probably a rusty-sort-of-area on cars in Northern areas.
__________________________________________________

Before you get under, pull the EFI fuse and crank the engine a bit, to hopefully empty some of the fuel from the lines (less spilled on you). Also, have the replacement filter on-hand, so that you can see the orientation of fittings, etc.

BE VERY CAREFUL not to smoke or have any type of open flame, etc. Saw where a mechanic is in the hospital with 70% burns all over (local news yesterday, July 4th). If he can srew up, so can you. If you are not sure, let a shop do it for you.

Do not loosen the 10mm bolts on the bracket. You will need the extra help when you go to loosen the lines. If you try loosen it beforehand, you may end up bending/twisting/kinking a line and turn 30 minutes of work, into a major repair.

You will need a 17mm socket/wrench to pull the line away that goes to the tank (this is the union bolt which uses the 2 crush washers that come with the replacement filter). This union bolt is on the filter, facing the passengerside of the car.

The other side requires a 14mm and 17mm (or 19mm) flare wrenches Remember, the filter-side (17mm/19mm) does not swivel. You have to hold it steady there, and unscrew the 14mm side of the fitting.

You can then remove the bracket & filter by removing the 2x 10mm bolts that hold it. Then remove/replace the filter on the bracket and reinstall. Make sure you keep the same orientation/flow direction.

It's not hard, just in a difficult spot... Easier to do it you are already dropping the tank, but removing the passengerside rear axle would make it easiest to access.

After reading everything I have, I agree that the filter definitely does it's job for up to ~100K, as indicated in some of the references posted. However, there are very few MKIIIs out there with less than 100K on 'em anyways.

Even if you believe it would go longer, for ~$18 from any autoparts, just make sure it's changed at every 100K or if you are not sure if the previous owner had changed it before. When I poured out the stuff from the old filter, it was brown. Seems like it did it's job well, but definitely time for a new one.

 

[DegreE]

I'm just going to go ahead and ask....






89 Supra N/A. Where is it?

 

[MKIIINA]

where it is on all supras, by the diff