I posted this on 3rd gen and didn't get much response so here it goes again:

Been getting crappy mileage in my 03 4x4 Cali truck since new. Almost always around 13 city/16 hwy. Changed my fuel filter at the dealer at 12k and mileage went up to 14/20 mpg for a few days and power was greatly improved. Gradually mileage went back down and after about 1 week was down to 15/17mpg. Now at 16k mileage is 11/13mpg . Changed my fuel filter myself today. There is sediment in the bottom of the filter bowl and the filter is charcoal black/grey with white spots all over. Reset the computer and did a 10 mile stop and go around the lake and mileage is 14mpg (city), that is good because I live in the mountains. I will try a long freeway run next week and see what it goes up to. But it seems very obvious that I am getting better performance and mileage after I change my fuel filter. I am pretty sure I got a bad tank of fuel when new or possibly from the dealer and now there is crap in my tank. I picked it up with 100 miles on the ODO.

Anybody have a similar experience or any suggestions before I go to the dealer and get reamed $$ to clean out the tank?

Thanks,

GT

 

The black/gray you're seeing is asphaltines, a normal constituent of all diesel fuel caused by uncracked or damaged molecules left over from the refining process. It's occurrence is impossible to predict, one day it's level may be high the next day low at the same station.
What plugs fuel filters- http://www.hastingsfilter.com/engineering/tsb_95-1.html

Best bet is to install a fuel pressure gauge so you can see if the filter is plugging.

If you do take it to the dealer try to use most of the fuel or drain it yourself. Most dealers have a hazardous waste disposal charge of $10 to $15 per gallon. Adds up fast.

 

I do not have a new truck with the computor for fuel economy, with that said, I have come to the conclusion from others here and other sites that they are not very reliable as to the correct figures??? The old pen and paper is the way to accuratly figure. The fuel pressure gauge is a great idea, also it is a good idea to buy your fuel when in town at a place that sells alot of fuel to the local trucks and construction guys. A few filter changes after getting fuel somewhere reliable is a whole lot cheaper than a tank drop at a dealer, if it is still a concern after a few filter changes, then I would drop it myself if you are able and if not take it in as infidel states with as low as you can get it. Goodluck,,,, Rick

 

Thanks, that's good to know. But I am mostly concerned with the sand-like sediment in the bottom of my fuel filter housing. It this normal? Its not a teaspoon full. Its more like 2-3 pinches of sand. I am worried the tank may have some sand in it.

Also, any tips on where or how to do a fuel pressure gauge sender?

Thanks,

GT

 

I changed my filter last weekend and drained it into a bowl, 2 boogers and some grit, looked like fine sand, the boogers looked like something that I cough up in the morning, The sand may be from the gravel too close to the dump hole

 

One thing I noticed is that the fuel drain valve will not completely empty the filter housing. I was on level ground in my garage and still had about 3/8 inch of fuel and grit/sand in bottom of housing. I took a clean rag like it says on the filter directions and cleaned the water sensors and wiped the sand and last bit of dirty fuel out. I had a few small globs of water but nothing major. Did you take a flashlight and take a close look in the bottom of your filter housing?

Thanks for chiming in. Anyone else have any opinions?

GT

 

I always had sand/grit in the bottom of the housing. I cleaned it out with brake clean. I then added a 50gal aux tank on my flat bed. It has a clear fliter housing and I can see all the fine particles that settled out really well. I run all my fuel thru the aux tank so the fuel is filtered once before it hits the lp and twice @ the vp-44. I believe there is a "sock" in the fuel tank for a filter too but not really sure? I have seen no "stuff" in the oe filter canister since adding the aux tank.
No matter though I always change the truck filter every 10k and the aux filter 2x/year.

Just my experience.

Copenhagenjunkie

 

There is a screen on the bottom of the tank fuel pickup module, actually pretty fine.
It is normally kept clean by fuel sloshing around in the tank unless things get really dirty.

 

FWIW, Just for info purposes, i havent seen sand in my filter housing while changing the filter. I fill up at the same station which is all concrete surface, and a few other stations here and there.
I dunno, is sand a "normal" thing to find in diesel fuel???

 

Unfortunately it seems like it happens a lot. I got a dirty tank of fuel in my 98 Cheby gasser and had to have the injectors replaced . We travel too much to use the same station so I guess I will just have to keep changing the filters.

GT

 

The sensor of the 1st gens screws directly into the filter bottom. I just unpluged the wires and drained the filter and goo into a bowl, and screwed the sensor into the new filter. The boogers weren't water, they were slimey as whale do. I should have cut the filter open and looked further, but my wife chunked it before I could, as far as the "sand" it looked like fine grit

 

Where you live in the swamps it is not surprising that you found that slime - it is microbial life growing fat and happy in the diesel fuel. Wherever you get your fuel from needs to have their tanks cleaned and then run some anti-microbial fuel conditioner in the tank at all times. The warmer the climate the more prone to growth in the fuel.

As long as the filter catches all of it there may not be any harm, but I would not want to be betting that some of it doesn't get by eventually.

 

I just changed my filter and found a little grit in the bottom of the housing. I wiped it out with paper towels.

Truck seemed to run a little better after the change, but I saw no difference in fuel pressure. The old filter only had about 1K miles on it. I am trying to track down a hard-to-start problem and did this to rule out the filter.

 

I just chased down a hard to start bug on a 97 CTD. I changed the fuel lines on this truck when I changed the starter contacts and had pulled the fuel filter off to get a little better access. The filter had just been replaced when I did this so I just put it back on and re-primed the system.

The guy started complaining about a small fuel leak and being hard to start a couple of days after I worked on it. Went back and checked to make sure all of my clamps were tight and that nothing obvious was wrong - found a weep around the fuel filter drain. Pulled and checked the filter and the o-rings around the top were stretched and loose. Apparently there was enough lack of seal to let air in overnight and lose prime.

All I did was change the filter and the problem went away and hasn't come back.

 

One important bit of info , when you are changing that fuel or handling it, please wear gloves and wash your hands good, there is a parasite that can live in diesel fuel, and it WILL make you real sick if you get it. My dad got it once and had to explain to the doctor what it was, luckily the doctor checked it out and was then able to treat him for it. He wasn't wearing any gloves when he was doing work re-fueling some of their heavy equipment, got a scratch on his arm, got sick the next day.