How clogged is clogged.

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Riddle me this, oh my bitog brothers, how clogged does a fuel filter have to be to cause problem?

The story. The much loved, ever popular "Luv" machine, (1986 Chevy Astro Van, 4.3 V-6 family farm mule) has been running poorly as of late. It started with an occasional "hicup." This progressed to a motorized burp and tail pipe foofie. This escalated to poor power, TBI backfire, (more like a mild "pop") and engine dying under load.

At first, I thought I had water in my fuel bucket, especially as fuel "tank" is actually a five gallon bucket that sits behind the drivers seat. I was thinking maybe rain had leaked through the roof, (which is very rusted and has holes big enough I can stick my fist through them) and gotten into said fuel bucket/tank. Took bucket out, emptied it, cleaned it, reinstalled, no dice. Same problem, (in fact, it started getting worse).

Next step, change fuel filter. I happened to have an old, used one I had saved from when I did my sister's chevy truck about a year ago. Both her truck and the "Luv" machine use the same filter and I had saved her old one for just such an occasion. Swapped filters, fired up the ever faithful "Luv" machine and she ran like a sewing machine. Drove it around, tried to get it stuck in some soft sand, (testing for load), she pulled right through with renewed power.

I head back to my shop pleased, convinced the fuel filter I removed must be totally nasty and clogged. I mount said filter in a vice and cut it in half to take a look/see inside ready to be impressed by fuel nastieness. Much to my shock and surprise, it wasn't what I would call bad at all. The paper element inside was a dark brown color, (the color of a paper grocery bag). There were some tiny flakes of metal, but I count these up to cutting the filter in half with a metal saw. There was no gook or grime or dirt that I could see with my naked eye.

My question therefore is this, how "clogged" does a fuel filter have to be before it starts making trouble? I've had them go bad in the past, taken them off, blown them out and the stuff that comes out is black as coal, but this one actually looked pretty clean to me. Is is possible there is hidden junk that I simply cannot see? Or is it possible this fuel filter simple failed through some kind of flaw?

Thoughts, opinions, observations?

BTW - it was a NAPA filter that had been on the "LUV" machine about four years.
 
One more quickie question about the filter - how does the fuel flow inside the filter? Does it come in through the inlet, flow around the outside of the paper element, then through the paper element and out the outlet or does it flow inside the paper element, the through the element and out the inlet?
 
Quote:
At first, I thought I had water in my fuel bucket, especially as fuel "tank" is actually a five gallon bucket that sits behind the drivers seat.


confused.gif
 
I have a newer version of the same engine as you, but.. I just went ahead and changed my fuel filter.

Sometimes the difference may not be exactly in pressure, but in fue volume and that will help.

It is one of those things that is so inexpensive that if you take it off, might as well put a new one back on.

Glad we dont have ubercomplicated fuel setups like an Audi or MB BlueTec...
 
Originally Posted By: GreeCguy
One more quickie question about the filter - how does the fuel flow inside the filter? Does it come in through the inlet, flow around the outside of the paper element, then through the paper element and out the outlet or does it flow inside the paper element, the through the element and out the inlet?


Outside to in. I'm guessing you may have had some water in the filter that was causing some problems, not necessarily the filter being plugged, but that's just my guess.
I recently took a filter off of a '95 Mustang that was put on at the factory. The only reason it absolutely needed to be replaced was because it had rusted through and was leaking.
BTW, I'm a big fan of doing maintenance on them and replacing them at least every couple of years.
 
Originally Posted By: TechnoLoGs
Quote:
At first, I thought I had water in my fuel bucket, especially as fuel "tank" is actually a five gallon bucket that sits behind the drivers seat.


confused.gif





...and people complained about the safety of fuel tank location in the Ford Pinto.....
 
The fuel filters I have lying around flow from the outside of the media to the inside. These are low-pressure filters, for carburetors.
 
Originally Posted By: pbm
Originally Posted By: TechnoLoGs
Quote:
At first, I thought I had water in my fuel bucket, especially as fuel "tank" is actually a five gallon bucket that sits behind the drivers seat.


confused.gif





...and people complained about the safety of fuel tank location in the Ford Pinto.....


Yeah, well the Pinto actually existed.
 
Nice story about the "LUV" rust bucket...

Strange why the engine was struggling if the fuel filter wasn't even that badly clogged. Perhaps the slightest decrease in fuel flow is enough to cause the problems you were seeing.

I've personally never even touched a fuel filter in all my years of automotive maintenance. All vehicles that I serviced with over 200k miles on them all ran like a great and were on the original fuel filter.
 
Back in the 80s my dad and I had Chevy products that would require fairly frequent changes in the fuel filter. We could cut them open and saw very little dirt. We wondered if the paper collapaed on some level (fibers) and this was the real problem?

John
 
Originally Posted By: John_K
Back in the 80s my dad and I had Chevy products that would require fairly frequent changes in the fuel filter. We could cut them open and saw very little dirt. We wondered if the paper collapaed on some level (fibers) and this was the real problem?

John


That's my guess. Moisture in the fuel meets cellulose fiber in the filter. Cellulose fiber absorbs water and expands thereby reducing flow.

I've also never replaced a fuel filter as preventative maintenance. In roughly 800,000 miles of driving, I've only had one that needed replacing.
 
Originally Posted By: Doog
Originally Posted By: pbm
Originally Posted By: TechnoLoGs
Quote:
At first, I thought I had water in my fuel bucket, especially as fuel "tank" is actually a five gallon bucket that sits behind the drivers seat.


confused.gif





...and people complained about the safety of fuel tank location in the Ford Pinto.....




Yeah, well the Pinto actually existed.


Gospel according to Saint John, chapter 20, verse 29.

(Although, if you go to the BITOG facebook page, you can actually see a picture of the wild and wonderful "Luv" Machine. If I have time, I'll post a picture of "gas tank."
 
Okay, head to facebook, type in Bitog in the search bar, there are pictures of my five gallon bucket fuel tank - please not the plywood safety wall between "tank" and "driver."
 
Originally Posted By: TechnoLoGs
Quote:
At first, I thought I had water in my fuel bucket, especially as fuel "tank" is actually a five gallon bucket that sits behind the drivers seat.


confused.gif




not-sure-if-srs.gif
 
You're scaring the city folk again GreeCguy, lol. Is it possible your fuel pump is dying? Sounds like the filter isn't an issue if it passes fluid.

Try just running it without the filter (temporarily) if you can, especially if you got a redneck gas tank. If it works fine then then you know you got it figured. I'm assuming its an inline filter canister like most cars?
 
Not necessary the case here, but it could be:

If the vast majority of the particles that clog the filter were large enough to not flow through, but also small enough that to really see them you have to use some means of optical magnifying, then the filter just might look usable to the un-added eye, while actually being clogged enough to not allow proper fuel flow.

In other words, it seams to me that the OP is making the assumption that particles that clog fuel filters are always going to be of size large enough to see with the un-added eye, when that may not be the case.
 
Originally Posted By: TechnoLoGs
Quote:
At first, I thought I had water in my fuel bucket, especially as fuel "tank" is actually a five gallon bucket that sits behind the drivers seat.


confused.gif



Since you and GreeCguy have the same engines, I think that the two you should get together and have a couple of beers and discuss said engines. Please report back to BITOG on how it goes, as we will all be very interested on the results.
grin.gif
 
Originally Posted By: RiceCake
You're scaring the city folk again GreeCguy, lol. Is it possible your fuel pump is dying? Sounds like the filter isn't an issue if it passes fluid.

Try just running it without the filter (temporarily) if you can, especially if you got a redneck gas tank. If it works fine then then you know you got it figured. I'm assuming its an inline filter canister like most cars?


It had to be the fuel filter as when I swapped it out, motor ran well, (power and response are very good). At first I thought water in my fuel bucket, but after cleaning it out figured it had to be filter as motor would crank up and run good for a minute or two, but then start to run like it was being starved for fuel. Summer is here and motor madness is about to begin as there are trees to pull, stumps to dig, brush to haul and mud to sling!

BTW - sorry city folks, didn't mean to scare ya
wink.gif
 
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