Fuel Filter Faq!

[MKIIINA]

Well this topic has seem to come up alot and after asking the mods if I could get this in the faq I'm hoping to make everyone's lives a little better. next stop world peace! ps this article isn't mine I just happened to find this over on another website. here goes!
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http://www.supracentral.com/content.php?article.47
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The TOYOTA way to change fuel filters
by Bob Shapton on Sunday 08 February 2004

Hey Supra guys. We have a former Toyota tech advisor on the Cressida list who is sharing his wealth of knowledge and experience with fellow Cressida owners. Here is his latest. Let me know if you'd like me to forward others he has submitted. They are quite long but very interesting reading. ==========================

When Toyota Engineers first developed their electronic fuel injection (EFI), they were searching for a maintenance free, self regulating fuel system that would continually maintain itself in optimum working condition, with NO maintenance. A fuel system customers would just love for it's low, low maintenance.

They knew that the fuel must be kept clean enough to pass freely through the fuel injectors, etc. without any clogging at all. For this dedicated filtering purpose "Nippondenso" developed a very special fuel filter with over ten times the filtering surface of any previous automotive fuel filter. It is inside a very strong, rust proof metal container with high quality threaded fittings, to withstand the high fuel pressures of EFI. The filter medium is carefully pleated, so a huge filter area can be installed inside a compact metal container. It is a truly fantastic fuel filter! "State of the art"!!!

The Engineers explained it this way. Their studies had shown that in some areas the current (small) fuel filters showed anywhere between about 60% to 15% clogging after 50K km. Therefore they had previously recommended their replacement at the 50K km service, because they felt that in some parts of the world the fuel filters may not make it to the next service at 100K km with much reserve to spare. They had found however that, overall, North American fuel was relatively clean.


There would be even less contamination entering EFI cars fuel filters, because of the new, large filter sock over the fuel pump pickup tube, inside the fuel tank that was made quite fine to protect the high speed electric fuel pump required on EFI cars. This pick up filter sock was somewhat "self cleaning" due to the sloshing action of the fuel in the tank bottom, and most dirt would just slosh off and be captured in the bottom of the fuel tank where it could do little harm.

Unless, of course, someone dumped a full bucket of mud into the fuel tank. They reassured us that with the smaller fuel tank filler neck it was very doubtful that this would ever happen. In any case no
filter could ever hope to cope with a humongous, catastrophic amount of dirt entering the fuel tank, and that it would require removal and cleaning of the fuel tank anyway.

Now! Compare fuel filters! If the older style smaller) fuel filter had a filtering capacity of 100 then this new EFI fuel filter with ten times the filtering capacity would be rated at 1000. In an "imaginary"
comparison test we could assume that since the old fuel filters may show 50% clogging at 50K km, those fuel filters were possibly replaced when 50 of their 100 filtration units were clogged at the time of the
specified 50K km service interval.


At 50K km the older fuel filter car would have It's smaller fuel filter replaced with a brand new factory replacement fuel filter, according to the factory recommended maintenance schedule, so it's reserve filtering capacity would be restored from 50 to 100. Since the EFI car neither required nor received any fuel filter maintenance it's larger 1000 unit filtration area would now have only a reserve of 950
units.


At 100K km inspection, the same recommended services would be performed, leaving the older fuel filter car with a fresh new fuel filter, with it's filtering capacity fully restored to 100. However, the EFI car would now have it's reserve lowered to 900.

After the 150K km service the older fuel filter car would be again restored to 100 units, while the EFI car would still have 850 units reserve.

At 200K km the older style would be restored to 100 units, and the EFI car would be left with 800 units.

At 250K km it would be 100 to 750reserve filtering units. At 300K km, 100 to 700. At 350 K km100to 650. At 400Kkm 100 to 600. At 450 K km 100 to 600.

And on and on………….Till finally at "one million" kilometres the older model would have it's EIGHTEENTH new fuel filter installed, restoring it's reserve filtration capacity once again to 100 units and
the EFI car still having it's original fuel filter would also have a 100 unit reserve filtration capacity.

Therefore it may, just may, be necessary to recommend that the EFI car should also have it's fuel filter replaced at one million and 50k km. We should live so long!

However, if the rate of accumulation of dirt was much lower than the predicted 50 filtration units per 50K km, during this one million km. test, then the EFI car may still have a very much larger reserve filtration capacity than we calculated. The lower dirt content would not have benefited the older, small fuel filter car at all. As well, the older style fuel filter would have contributed eighteen discarded fuel filters into a land fill, and at even five bucks a filter, cost
the customer "ninety" dollars in maintenance. Eureka! No more fuel filter replacements! Fuel filter teplacement is finally just a relic of the past! WOW!


At this time (twenty years ago) fuel filters were completely deleted from all Toyota service maintenance schedules for all EFI vehicles. The oil change, air filter change, etc., remained, and were covered in
great detail in all factory service manuals, etc. But, all references to "fuel filter replacement" were deleted for all time from all factory service manuals. A whole half page of the factory service manual is devoted just to inspecting fuel pipes for any kinks or
deformation (including illustrations of a leaking fuel line). Text and illustrations of the precise, recommended placement of the rubber fuel line's spring hose clamp is fully covered, but absolutely NO mention
whatever of "fuel filter replacement". There is absolutely NO mention of any fuel filter replacement in any owner's manual (does anyone ever read them?) Do you think that the factory repair and owner's manuals
were trying to tell people something??? Did you get the hidden message??


The fuel filter was considered to have a service life far exceeding the projected life of the majority of most of the vehicle's other components, and was fully expected to outlast the cars. Replacement of the fuel filter made much less sense than the replacement of the fuel tank or the replacement of the ignition key, or the trunk lid emblem.

Great! Parts people were instructed to anticipate virtually zero fuel filter sales. One less maintenance service problem??? Great! Wow! Customers would love this!!!

But, much to the dismay of many Engineers, fuel filter replacement sales for EFI equipped cars remained telatively high. Why? Discarded fuel filters were reclaimed, opened up and found to contain almost no
dirt at all. Why were people replacing them??? The best laid plans of mice and men often go astray! Who knew why???

There was great concern that there was a high risk involved because some dirt could accidentally enter the fuel system, downstream of the fuel filter during the fuel filters replacement, and damage the downstream fuel injectors etc. There was also concern that all fuel line fitting gaskets, etc. would not be properly replaced with new ones, and that the fittings torque might not be correctly reset to factory specifications, as this was a very high pressure EFI fuel line.

[MKIIINA]

This part of the EFI system was intended to be serviced "only" by trained mechanics, yet it was apparent that it was being serviced by people who, clearly did not know what they were doing. There were many complaints that replacement fuel filters were much too expensive, and much too difficult to replace. Why were people still replacing them??

Nobody seemed to know.

Believing that the fuel filters were too highly visible they were painted black, and the Engineers tucked them up under the intake chamber where they were very difficult to see or service, on the 7M-
GE models, to discourage needless replacement, but people kept on replacing fuel filter, despite the difficulties. Why???

It was suggested that a sticker be applied to warn people not to replace the fuel filter. This had been done previously to discourage needless spark plug replacement. The warning sticker helped, but many
people simply ignored the warning sticker and replaced the spark plugs anyway. Another very hard to break habit, that still continues today. Nobody wanted to commit to stating "NEVER" replace fuel filters, as
that's a very, very strong statement. Should the sticker read:

WARNING! Replace fuel filter every one million kilometres, or 25 years, whichever comes first!

I think a sticker on the fuel filter stating: Warning! "This is not a fuel filter", may prove to be more effective.

Do you think that fuel filter replacement is genetic?? My father always replaced his spark plugs and fuel filter, and I am fully committed to continue replacing mine too, and to the preservation of this fine family tradition. I don't know???? I just can't explain why
people insist on performing these seasonal, cultural, fuel filter rituals. It must be passed down from father to son as it's been going on for over 20 years! No warning sticker can ever overcome that kind
of dogged determination.

Why were people in North America still replacing these costly and difficult, and risky to replace fuel filters with NO instructions or any valid technical reasons for doing so??? It soon became apparent
to the Engineers that fuel filter replacement was so deeply ingrained into the North American culture that people just could not break their highly addictive fuel filter habits.

I had many phone calls: "Where the hell is the dam fuel filter any way?? What lame brained idiot put the fuel filter up there where I can't even get at it? He sure didn't know a dam thing about what he was doing! I could sure teach him a thing or two about engineering
cars." All I could say was " Why are you replacing the fuel filter?? Why?? The answer was usually " I always replace fuel filters. I won't ever risk having a fuel filter plugging up. So I asked, "Have you ever had one plug up???" Of course not stupid! Because I always
replace them. That's why" How can you ever argue with such success???

I suppose that if people derive some deep inner spiritual satisfaction by performing their traditional "fuel filter replacement" ritual, they
are free to continue to do so! it's a free Country!! But I really wonder why they insist on doing it??

Instead of applause, the poor Engineer receives insults!

I see from reviewing many of the posts on this site that the grand tradition of fuel filter replacement continues on unabated. It continues to be, by choice, the first recommended line of attack, to resolve almost any performance problem. I see posts from owners whose crankcase breather pipes must be so badly clogged with hardened crud that a "Roto Rooter" couldn't clear them (engine oil forced out
through the distributor??), I'll bet those same vehicles have probably had their fuel filters replaced. WHY? I have never, ever seen the replacement of a fuel filter successfully resolve any problem. Why do people always recommend first replacing the fuel filter??? Any suggestions????

I suspect that with tens of thousands of Toyota fuel filter sales, that a great many people are accumulating a nice nest egg to finance their early retirement. Americans spend many millions of dollars a
year on fuel filters. Would this money not be better spent elsewhere?

Perhaps a: "I gave up replacing my fuel filter so that a starving child could eat! , type of charity. Are fuel filters car owner's pacifiers, or security blankets??


I have cut discarded fuel filters apart , but I have never found anything inside that would ever restrict fuel flow. They appeared almost as clean as new inside?? If anyone has ever found one of these
"Denso" fuel filters that was ever actually clogged with dirt?? I would sure like to hear from you. They may exist?? But, I have not found any in twenty years. Please post if you have ever replaced a fuel filter because there was real evidence that the fuel filter was actually restricting fuel flow, and a replacement filter actually solved the problem by restoring the fuel flow. Please post if one of these fuel filters has ever passed a particle of dirt that damaged a
fuel injector.

I believe that the fuel filters very, very clean passing through these fuel filters as I have not yet seen a dirt clogged fuel injector.

I have found fuel pump residual check valves leaking from what I assumed was a spec of dirt (too small to see) as discussed in my previous post on fuel pumps, but I have always believed that this was because the fuel pump check valve was only protected only by the fuel pump intake filter sock, and not by the actual in line fuel filter.

The fuel pressure regulator never seems to leak residual fuel line pressure. I think it's because it's fuel is all completely filtered??? Anyone ever found a leak fuel pressure regulator???

I have only experienced one incident of fuel supply clogging, and that was because someone had attempted to repair a fuel tank by pouring an epoxy treatment inside to seal a damaged fuel tank The epoxy coating
peeled off and completely clogged the fuel pump filter sock, inside the fuel tank, but the fuel filter was still OK. I recommended replacement of the fuel tank and the fuel pump, as it had become overheated while sucking away on it's plugged inlet filter sock. Never
had a restricted fuel filter though.

Please post if you have ever found a restricted fuel filter????

Anyone???

Please post if you have ever replaced your Cressida's fuel filter. Did it improve your car's performance?? Did it bring you security, peace of mind?? This question has haunted me for a long,
long time(20 years).

Come on! Cressida Owner's!!!! Let's see some posts!!!

Own up!!! How many of you are victims of the "great fuel filter myth"?????


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[fatbob55]

Great Post! I tried replacing my fuel filter once during a tune up but gave up when i tried to reach it. They sure did make it a pin in the ass to get to. Maybe now i can sell that fuel filter I bought. Hey, I have a fuel filter for sale. PM me if you want it. I think I'll sell it for 50 bones.

Thanks

[Kroze]

wtf. some cliff notes? too late for this. lol

[Jeff Lange]

Originally posted by fatbob55
Great Post! I tried replacing my fuel filter once during a tune up but gave up when i tried to reach it. They sure did make it a pin in the ass to get to. Maybe now i can sell that fuel filter I bought. Hey, I have a fuel filter for sale. PM me if you want it. I think I'll sell it for 50 bones.

Thanks

Does the Supra have some fancy fuel filter? I just replaced one in my Tercel for $13.

[ZaZZn]

When running 440's at 15 PSI and then 550's at 15 PSI I was still running EXTREMELY lean 13.5:1 and very hot EGT's I tried adding 30% on my S-AFC but it didn't seem to help on the high RPMS..

After replacing my Fuel filter my problems vansihed.


So I guess mine was indeed clogged.

[NeSSuS-GTE]

Considering that the replacement time for the small fuel filter was likely gauged on significantly less fuel throughput than a BPU++ MKIII, I would tend to think its real-life filtering capacity would degrade at a greater rate than the theorectical predication made above. But it certainly still works at 100,000 miles, which ain't bad at all... :)

[Interex_87]

HTH: http://users3.ev1.net/%7Ehmillerjr/ff/

[strangercbx]

My problem is one of performance. I'm sure the answer is almost simple, but then again, perhaps not. I have a '87 supra turbo, runs great as long as I don't plan to accelerate beyond 2500-3000 rpm or simply go over the speed limit. Now this might be great for the young..but I hate it!! Have tuned car, but was told to replace fuel filter, as this could be the problem. Reading the above post concerning the long life of the fuel filter...I wonder.
So my question is simple: if not this filter, what should I be looking at?
I love the car, but really, really hate the speed limitation. Please help!

strangercbx

[chevydude]

HTH: http://users3.ev1.net/%7Ehmillerjr/ff/

lol, I remember seeing that walk through and said, "forget that!" and I just took it to the dealer. I usually don't but it was dead cold outside, and it was troublesome.

[outofstep]

I don't think fuel filters have sexuality.

Man, them no-capital Qs can throw you off.

[strangercbx]

Okayyyyyyy, does anyone know what a bad air/flow meter on a turboed 87 would do?? I believe mine to be shot..and its having a very difficult time reving up. Is this one of the problems associated with the meter? Please advise!!

[AGlobalThreat]

The AFM is right before your filter. It will have a black cover on top and a cord of wires coming off the side of it. Make sure the cord is plugged in all the way and is not damaged, and if your problem still persists, buy another AFM from a member on this forum in the for sale/wanted section.

BTW please post this in the MKIII General/Technical section next time, this thread is about fuel filters and is completely off topic. :stickpoke

[Larry_A]

I witnessed a MkII at RD Dyno whose Tech-II fuel map changes had zero effect. After much deliberation & wasted time, we took the fuel filter apart & it looked like it was full of baby shi+.

Filters get clogged.

Sorry, swapping fuel filters will never no away.

Take care.

[quakerlt]

And what are the symptoms of unclean fuel filter?

[profuse007]

on all toyota, you do NOT need to replace fuel filter, ever.

wtf. some cliff notes? too late for this. lol

[quakerlt]

on all toyota, you do NOT need to replace fuel filter, ever.
probably, that sentence should fulfill this FAQ section :bigthumb:

[BlackDevilSupra]

As with almost everything in life, a curious bunch exist. Ya know, the ones that ignore cautions and warning eventhough there is substantiated proof. See Larry's response a few post above. I wish I kept my old filter or had taken pics of the "diarrhea" like gunk that dribbled from it upon removal. If you don't believe it needs periodic changing, why not just remove yours and perfom a condition inspection? You'll immediately be convinced one way or the other ;)



probably, that sentence should fulfill this FAQ section :bigthumb:

[quakerlt]

Well, I've heard or read somewhere that it needs to be replaced ech 15 000km (10k miles). Bullshit?
According to previous owner, I should change the filter in about 1000miles. We'll see what happens then. I'll take some pics in order to add more information to this section ;)

[Afunk]

Dude, change your filter NOW...don't listen to that bullshit...I just changed mine and the gunk in it was black; the gas poured out of it was black as well. It looked like the original filter, with 200K miles. 1 million miles...haha...I should post pics.

[BlackWidTan]

Dam the 14 nut is completely frozen. I really wanna change this thing but that flickin nut is the only problem.

[L-Deuce]

I know this thread hasnt been posted on in well a long ass time... I work in a shop that changes fuel filters often. I personally changed mine in about 20 minutes. The one that was on there before was clogged and I was getting TONS of hesitation in hard acceleration before and now it's like butta. =)
So I am and always will be a true believer of fuel filter replacement.

You can pick the filter up at O'Riellys for about 16 bucks (maybe more I had a shop discount) and you don't have to disconnect the banjo style bolt (the one that is usually rusted shut, I know mine was). There is another connection on that line lower down and easier to get to. Of course you still have to get the filter down but you can just use an impact gun to take the bolt off after you get the filter down. NOTE = DO NOT use the impact gun to put the bolt back on the new filter that's bad mojo. I can take a picture of the connection I'm talking about tomorrow.

-Deuce.

PS I live in Nebraska where they have the "higher octane" 10% Ethanol gas and that's what the owner before me used. That may be a reason it became clogged.. I dunno. I still want to slap him for his lack of maintenance.

[suprashy]

I just changed my fuel filter when I installed the Walbro, and I'm no expert in turning wrenches. It wasn't bad for me. Some have broken the lines due to rust, age, etc. but I was able to preserve the stock line. I did break the line that goes from the banjo bolt to the tank though. This required having to change the fuel pump bracket, bec. the lines and the bracket are one piece, (unless you make your own SS lines). As stated elsewhere, I highly recommend PB Blaster. Spray the bolts, use a 14mm FLARE wrench, and IIRC, a 19mm that holds the nut that is connected to the filter (this is the side of the filter that goes to the fuel line under the car). I noticed clean fuel drip out of my filter when I removed it, but after 16+ years, and with a full turbo/fuel upgrade, with intentions to keep the car for a very long time, isn't it prudent to change the filter? Original Toyo filter is only $30, and it comes with the bracket!

Suprashy

[L-Deuce]

http://i41.photobucket.com/albums/e260/Lannyrx7/ffline.jpg

This is the line I'm talking about. It's about a foot long and connects to the banjo bolt side of the fuel filter. This fitting is right next to the rear diff. and is alot easier to remove than the banjo bolt from the filter itself while it's still on the car.
Hope it helps.

-Deuce

[mk3tt1jz]

if a filter was made to never be changed out their would be no replacments for that car. not only that but any thing with a filter system is bound to get clogged up sometime. and if you think that you shouldnt change the filter then you have problems sorry to say. mine was so clogged the car barley rand and cut out with slow revs. all better now thanks to a new filter

[letxen3]

i just helped my friend replace his 1990 supras fuel filter and it was easy. PB blaster a must before you start to wrench it also helps rid of the rust.

also if you put your hand behind the differential there is a sweet spot with lots of room to work your 14mm wrench. (there goes your certified toyota service tech for ya lol)

we put the old fuel filter in clean bowl with water to see if it was dirty and i wouldnt say it was very dirty but it did have some.

i agree why would they have non toyota replacement fuel filter if it wasnt meant to be changed.

also for the normal person it may be awesome back in the day not to have to replace it.

but we here work on the cars to make them more powerful and changing filters is a must inorder to prevent and just to be on the safe side. why put alot of money in your engine if you cant simply have a nice fresh start fuel filter.

[mkiii 4 life]

where is the fuel filter located on a 7m-gte

[letxen3]

i will take some pictures and post. but its basically between the gas tank and the rear differential deep deep inside need a flash light to see it.

[TROY]

i just changed my fuel filter... and it solved a problem i was having when i would mat it the car would jerk 2 or 3 times as if the fuel could not keep up with the motor. changed the filter and BAM problem solved. no more jerking under initial hard acceleration.

sure they are a great filters but nothing lasts for ever...

[DegreE]

So, where is it on a 89?

[TROY]

above the back diff

[Satan]

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.

[aaronc222]

I can't beleive that ANYONE would think a fuel filter would last that long. Especially an engineer.

And as far as effectiveness of changing a filter:
When I had my 95 Celica (7AFE), I was a lot less mechanically inclined. It had ~150k, and had developed a strange miss/stumble at both idle and wot. I tried the normal stuff first, spark plugs, cleaned the K&N, took it into Toyota to have the timing set... a little better but still there.
So I started thinking, crap it's time to do the injectors(they were ticking anyways), but thought I'd try the fuel filter before dropping a bunch of cash on injectors. Worked like a charm, it was smooth all through the power band just like it should have been after a dealer tuneup. I even advanced the timing a few degrees and gave it some 93, ran like a new off the lot car. I was even getting 33-35 mpg CITY on a regular basis delivering pizza(due to gearing, the ST Celicas tend to get better city mileage than highway, mine ran over 4k in 5th to do 70mph)

The whole experience made me a firm beleiver in changing a fuel filter. I still don't think it should be the first thing you do when there's a problem, but it shouldn't be forgotten. Which reminds me that I've been putting mine off for too long now.

[ddouglas77]

on all toyota, you do NOT need to replace fuel filter, ever.

WRONG. TSRM recommends filter to be changed every 15000 miles or 12 months.

[Jeff Lange]

WRONG. TSRM recommends filter to be changed every 15000 miles or 12 months.

Where?

I don't doubt that it might say it, but I've never read it myself, I don't think.

Jeff

[micit]

Please note TOYOTA needs to supply supra owners with a DAMN page in the manual for replacing the fuel filter. I'm calling them, lets start a figin petition. I just spent over four hours on a computer just to make sure i'm taking the right part off before i do. And i own the service manual.

[barkz]

hello '08

[micit]

i haven't been on here in ages.THE fuel filter has been a pain in the buttocks. I'm sorry i can't post pics need a new camera, but it looked like i was pouring oil out of my fuel filter. definetly change it.

[IamWedge]

4 hours eh?
Ya know.... the car is over 20 years old. What do you think Toyota is gonna do? Recall all the TSRMs? Then reprint them? I think common sense would have dictated following the fuel lines till maybe you came across your fuel filter. BTW.... be prepared to bust your knuckles on that banjo bolt. The "oil" is sediment. All the crap that was in your tank over 20 years.
Filter location
http://www.supraforums.com/forum/showthread.php?t=521795&highlight=Filter+filter+location
http://www.supraforums.com/forum/showthread.php?t=412595&highlight=Filter+filter+location