Fuel Filters

[terrylamar]

Exactly what are the ramifications of having dirty fuel filters. I have a CAT ACERT engine. I was low on fuel and my engine died. I thought maybe there wasn't enough fuel in the tanks to make it to the engine. I happened to break down on the highway in front of another driver's house. He came out to help. We ended up changing the filter/water separator and the fuel filter, both were dirty. Once we got them changed and primed the engine ran. A couple of other symptoms I've noticed are when idling sometimes there is a miss in the engine and no mater what I do my fuel mileage has been dropping. TMC has us put the truck in the shop every 25,000 miles. I suspect the shop isn't doing the proper maintenance.

Were the dirty filters causing my fuel milage to decrease?

[allan5oh]

I suspect you're getting air into the system.

[Blind Driver]

Got a see-thru filter? As the filter gets dirty, the fuel level will rise. When it gets near the top, it needs to e changed.

[bob h]

your engine likely shut down due to fuel starvation (i ran outta gas ?!?)

it didn't re-start because the fuel system was aerated (stand of supply fuel was displaced by air)

it then started after replacing the filters because the new filters were filled and the fuel system was primed (air purged from fuel system).

most diesels are very difficult to re-start after the fuel system has been run dry ... some of course more than others ........ cat ... mbe ?

it's funny how the fuel filter restriction is always blamed despite the fact that the engine had no power complaints leading up to the shut-down... hmmmmm

[Kranky]

your engine likely shut down due to fuel starvation (i ran outta gas ?!?)

it didn't re-start because the fuel system was aerated (stand of supply fuel was displaced by air)

it then started after replacing the filters because the new filters were filled and the fuel system was primed (air purged from fuel system).

most diesels are very difficult to re-start after the fuel system has been run dry ... some of course more than others ........ cat ... mbe ?

it's funny how the fuel filter restriction is always blamed despite the fact that the engine had no power complaints leading up to the shut-down... hmmmmm

And it's even more fun to get it primed up again if someone tried to keep driving it until it just wouldn't go no more, instead of shutting it down at the first sign that it was running out of fuel!

[allan5oh]

exactly bob, that's why I suspect there's a small leak somewhere.

If that's the case, it will happen again in short order.

[terrylamar]

Well, the first sign it was out of fuel, was that the engine shut down. Out of fuel as in the engine wasn't getting fuel. There was fuel in the tanks. Whether it was being sent to the engine is another question. Once both filters were replaced, and they were dirty. Priming them was as simple as filling the filter with diesel before it was installed and filling the water seperator with fuel through the small cap at the top. The engine ran fine after they were changed. Far beyond the fuel that primed them. Perhaps there wasn't enough fuel in the tanks and it began to suck air and the engine stopped. I don't know, why would it then run afterward just fine? I'm not a mechanic and I don't play one on TV.

[allan5oh]

Because it will slowly suck in air. Until it gets to a point where it can't suck in any more fuel. Fuel pumps can't pump air very well, as we all know.

Do an experiment, run your tanks low. If it does it again, it might be in the pickup tube.

If it just does it randomly, it's further down the line.

Look at the fuel filter bosses, probably the first one. That's where I had my problem.

To test your system, plug one tank vent tube, and put a *small* amount of air pressure into the other side and seal it.

Start from the back, work your way to the front. If you find bubbles, you just found the problem.

Could just be that the previous filters weren't tight. That's happened more then once.

[terrylamar]

I seemed to have fixed the problem. Maybe it is still too early to tell. I was asking if dirty, clogged filters would cause the engine to die, probably so, and if it is causing poor fuel milage.

[allan5oh]

Yes, it would also be a slow painful death, not instant.

[bob h]

[quote="terrylamar"]Well, the first sign it was out of fuel, was that the engine shut down. Out of fuel as in the engine wasn't getting fuel.

"out of fuel" generally indicates that the level is too low

There was fuel in the tanks. Whether it was being sent to the engine is another question.

here's some important info that was left out of the original post

Once both filters were replaced, and they were dirty.

cotton swab test??? how did you determine that the fuel filters were dirty... appearance alone?

fuel inlet restriction is the test that will tell you the serviceability of your fuel filters

Priming them was as simple as filling the filter with diesel before it was installed and filling the water seperator with fuel through the small cap at the top. The engine ran fine after they were changed. Far beyond the fuel that primed them. Perhaps there wasn't enough fuel in the tanks and it began to suck air and the engine stopped.

perhaps

I don't know, why would it then run afterward just fine?

becuase it is no longer sucking air... did you add fuel to the tanks? did it die as the fuel was sloshing around under vehicle movement?

I'm not a mechanic and I don't play one on TV.[/quote

that's probably why you're asking ;0)

[bob h]

I seemed to have fixed the problem. Maybe it is still too early to tell. I was asking if dirty, clogged filters would cause the engine to die, probably so, and if it is causing poor fuel milage.

fuel filters on hd diesels don't often cause enough restriction to stall the engine due to the fact that they are changed on a regular schedule... if you notice power recovery and fuel mileage benefits each time you do your annual fuel filter change, it's possible that they should be changed more frequently

[sodbuster]

I just replace my filters and cleaned the strainer. I only had this truck since March, and all the filters looked somewhat new. I had been running on flat land mostly. But when I started going on trips that had long grades and was loaded I started notice a loss of power. The first was a loss of turbo boost for a given engine RPM. It was like having a govener and it was cutting the fuel. It got so bad I was wondering if I was going to make my delivery. After I dropped the load and was I the way home I had no real problem empy. Sure enough I replace the filter and cleand the striner. And no more problems.

[allan5oh]

fif you notice power recovery and fuel mileage benefits each time you do your annual fuel filter change, it's possible that they should be changed more frequently

ANNUAL? Damn!

[terrylamar]

I am a Company Driver. I don't have much say when and what is done, although on my last PM I mentioned that the air filters were dirty and they replaced them. Recently, I had a hose that rotted out. I guess that should have been replaced during the PM and wasn't. I am figuring out perhaps I should take a more proactive approach. What I need is a list of things that should be done during PM. So I can make sure they are being done.

I am still having problems with my fuel mileage. It is still going down. I made a concerted effort at improving it with progressive shifting and watching my speed. It was improving, but the last couple of weeks it has been going down again. I haven't noticed any change in my driving style and I haven't been running that many hills and mountains or carrying particularly heavy loads. I'm wondering what may be causing the decrease in fuel mileage?