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Need Fuel Filter Help NOW!!!

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Old 03-01-2007, 11:24 AM
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Originally Posted by TNRabbit

A fuel filter has NOTHING to do with an engine running lean or rich. The ECU, injectors and intake air do that. What a fuel filter WILL do is reduce the flow of fuel to the injectors. The fuel system normally runs in the low to mid 40s PSI pressure. If you suddenly apply full throttle (WOT) with a clogged filter, it's going to reduce the pressure somewhat until the pump catches up. Therefore, you would probably only see any difference with a sudden appplication of WOT or a steady state WOT at high rpms (top speed, for example).

It would have to be PRETTY DANG BAD to affect low rpm response; I don't think that I've ever seen one THAT bad. A clogged filter will also make everything work harder to make up for it; notably, the fuel pump.

Any fuel economy increase from a fuel filter change alone is going to be very small, but I still can't understand why it would go DOWN unless your newfound power is going to your head (foot)...
Well it was just a theory, I have no real world test data.
Old 03-01-2007, 12:28 PM
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Originally Posted by TNRabbit
That makes NO sense whatsoever! Did you change something else besides the filter??
No I didn't.
Old 03-01-2007, 12:29 PM
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Originally Posted by Barnstormer
In reference to the loss of MPG after the filter switch, are you sure you put the filter in the right way?
I noticed when I was changing my filter the other day that the previous filter (by the previous owner) was installed backwards. I don't know what the filter is like on the inside, but trying to flow it backwards might restrict fuel flow. When installed correctly, the thick "flange" end of the filter should be forward.
IE, the line from the tank goes to the bigger end (which should face the front of the truck) and the line to the engine comes from the smaller end (rear) and heads up to the fuel rail.

Just my .02

B
It was done by my certified toyota mechanic/friend of the family for 17 years. There is no way he would have messed up and put it in wrong.
Old 03-02-2007, 10:30 AM
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Hey whitetaco02 below is a messege sometime ago i posted with your forum ......

Originally Posted by scoolro
Hey whitetaco02, wow!! I thought it onlu happened to me. I had an 88 4runner 5speed v6 and when I changed the fuel filter my Kilometers dropped. I now have a 91 4runner 5speed v6 same engine type and changed fuel filter and again noticed big drop in kilometers. So few months later I bought another Fuel filter, this time spent the money to buy stock toyota fuel filter and still no change in Kilometers. When I had the truck I had about 335 KM now I get about 270km. what could it be? Anyone please have an idea why this happened and what I can do to improve fuel consumption. I haven't changed my oxygen sensor yet because engine light hasn't lit up. So i beleive the O2 sensor is okay. I have tried many times to figure out what is going on but with out any luck.

So if anyone has anyideas PLEASE! PLEASE! PLEASE! help.

Many thanks in advance for any help,
Scoolro

I am still trying to figure this out. Going to many forums and still no luck. Does anyone have any ideas why the loss of kilometers\mileage.

Both 4Runners I had same engine type and Loss of Kilometers as soon as I changed the Fuel filters.

Sorry for reposting but there must be a reason for this.

Thanks Again,
Steven
Old 03-02-2007, 12:06 PM
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Well here's another theory Maybe since changing the filter the fittings are leaking?
Old 03-02-2007, 03:00 PM
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Originally Posted by mt_goat
Well here's another theory Maybe since changing the filter the fittings are leaking?
maybe, but there is no smell of gas at all and there is no drip of gas on garage floor. thanks for the reply. anyone have an idea why this is happening??
Old 03-02-2007, 03:54 PM
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how can i tell? how would i found out if the fittings are leaking? forgive me if this is a dumb question.

steven
Old 03-02-2007, 05:41 PM
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Originally Posted by scoolro
how can i tell? how would i found out if the fittings are leaking? forgive me if this is a dumb question.

steven
Yeah if you keep the truck in an enclosed garage you would smell it for sure.
Old 03-03-2007, 06:03 AM
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Change in fuel economy

Is it possible that with a slightly plugged "old" filter the injectors didn't have enough fuel pressure to spray the appropriate amount of fuel per cylinder, and once changed the fuel pressure is up to where it should be and thus causes more fuel usage? Making economy go down but should increase power and perfiormance?
Old 03-03-2007, 06:44 AM
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Wow...all these posts and no resolution yet!
Old 03-03-2007, 11:13 AM
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It was the difference between night and day, when I changed mine recently. More power all around, esp. low end. This would help my fuel economy, if I were to drive as slow as I had to, with the old filter. But, I don't usaully. It was extremely filthy, maybe had somethin' ta do with it.

Last edited by MudHippy; 03-03-2007 at 05:10 PM.
Old 03-03-2007, 12:28 PM
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Anyone that has the 2nd Generation 4runners how many Kilometers do any of you get with a fill up? i get around 270km. Before i use to get 320 to 350 with old filter. So as you can see I have some concern with the fuel filter changes on both of my 4Runners. I lost some kilometers with the filter change on both 4Runners. My 88 Runner and now my 91 Runner.
Old 03-03-2007, 04:31 PM
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bolts

I have 1 bolt in my fuel filter.. 1 is pleny IMO.. I always leave a hard bolt to get to out, if i think it will be ok without it.. It sure makes next time alot easier..
Old 03-03-2007, 05:25 PM
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Maybe when you did the job on your fuel filter you leaked a couple gallons of gas, thereby throwing off the economy for that particular tank of gas

TNRabbit's response is the best one I've heard yet.
Old 03-04-2007, 03:53 AM
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i think the engine gets the fuel easier with the new filters, so the injectors probably spray more. thus causing less fuel mileage but slightly better performance
Old 03-04-2007, 05:09 AM
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I was just reading through the thread and it appears we've hijacked the H@LL out of 90inworks original question! How is it working with the new filter?
Old 03-04-2007, 07:37 AM
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I am sorry if I swayed the orginal post. To all of you I am sorry. Just that this loss off fuel is starting to annoy the crap out of me. When I read that whitetaco02 had the same problem I just had to post that I have the same problem myself. Here in Canada gas went up alot. From .72 cents to $1.02 a liter. Some gas shortage the gas companies claim. Which is full of BS. So I want to get the Gas problem of mine fixed if possible. Just lost lots of kilometers when I changed my filters. Maybe another tune up will help. Again sorry if I swayed the post but again anyhelp is appreciated.
Old 03-04-2007, 08:18 AM
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Originally Posted by scoolro
I am sorry if I swayed the orginal post. To all of you I am sorry. Just that this loss off fuel is starting to annoy the crap out of me. When I read that whitetaco02 had the same problem I just had to post that I have the same problem myself. Here in Canada gas went up alot. From .72 cents to $1.02 a liter. Some gas shortage the gas companies claim. Which is full of BS. So I want to get the Gas problem of mine fixed if possible. Just lost lots of kilometers when I changed my filters. Maybe another tune up will help. Again sorry if I swayed the post but again anyhelp is appreciated.
Have you tried to pull codes on it yet?
Old 03-04-2007, 08:39 AM
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Hey no problem about the tread i got my answer what ever you guys want to to go for it lol
she seams to be running good i just filled the tank so we will see how long it lasts
Old 03-05-2007, 07:50 AM
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thanks 90inworks didn't mean to alter your tread.

So can anyone else figure out what the problem me and whitetaco02 are having with our filters??

I will try to make a a new tread about this fuel filter problem and mileage.

Thanks in advance,
steven


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