Black Grit in Fuel Tank - What Is It?

Messages
77
Location
AL
Thread starter
Well, I haven't posted in a while due to work and other commitments. However, my son's 1996 Tacoma X-cab 4 x 4 with 3.4L and 5 speed has a fuel issue. We have had it for 4-1/2 years. It started acting up about 2 weeks ago, when he was a highway trip. He had filled up the gas tank before leaving, and a little later his truck was losing power and sputtering on hills. He called me and I said that he might have some water in the gas and find a parts store and get some water remover. He did, and it seemed to be better for a while. However, on his return trip, it started acting up again. So when he got home, the next day I replaced the fuel filter. I had replaced it before, about 12K miles earlier. The gas that came out of removed filter's inlet (tank side) had a lot of trash in it when I turned it up to drain it. Well, about a week later, same symptoms with the new filter installed, again while on a highway trip, and after filling up again, but at a gas station I use for all our vehicles. When he got home, after a few days (rained here) I removed the new filter, and just like the previous one, lots of trash when I drained it and blew through it backwards. I siphoned out his tank (BTW, unleaded tastes different than leaded, which says how long it's been since I siphoned gas). Anyway, I drained some gas into a white 5-gallon bucket. Almost immediately I saw a lot of black crud. After pouring this gas through a coffee filter into another container, I tested the crud with a magnet, but it isn't magnetic. When dry, it feels like very fine black sand. I finished siphoning out all the gas that I could, and filtered it all twice before putting back into the tank. I blew out the filter backwards several times after filling it with gas. Put everything back together today and let him drive it. Okay for about 10 miles and then back to the sputtering again. I guess I should have replaced the filter again, but I'm trying to figure out what this crud is. I don't think it's charcoal from the evap canister because it doesn't break down when I rub it between my fingers, and charcoal would leave a smear / stain on my fingers. I don't think that it's sugar or other granular fine put in it due to vandalism, because he has a locking fuel door. I guess I'll siphon out as much as I can, and change the fuel filter again. I read another forum about emptying the fuel tank, where someone said that I could turn on the ignition, and the fuel pump would run. I tried this, but didn't get much fuel out of the line. Is there a trick to this? I had the gas cap off when I tried.
 
Messages
2,700
Location
USA
On most vehicles you would have to jump the fuel pump relay to make the pump run without the engine. It only runs for a few seconds if you turn the key on but don't start. Many Japanese cars have a drain plug on the gas tank so you don't have to do that though. After the tank is as empty as practical, remove tank and clean it out. There should be a "sock" type pre-filter on the fuel pump to keep large chunks from making it to the main filter.
 
Messages
8,855
Location
Marshfield , MA
A 23 yr old truck is bound to have acquired all kinds of debris. I would blow compressed air through the hard lines , just cuz, and pull the pickup in the tank as well. E 10 tastes good compared to leaded reg'lar grin2
 
Messages
14,540
Location
Upper Midwest
Originally Posted by andyd
A 23 yr old truck is bound to have acquired all kinds of debris. I would blow compressed air through the hard lines , just cuz, and pull the pickup in the tank as well. E 10 tastes good compared to leaded reg'lar grin2
I used to think the same thing, a few years back when the fuel pump died on my old BMW I expected to see all sorts of junk when I opened up the tank. Instead it was pristine inside, there was even very little of anything on the pump sock. I was surprised.
 
Messages
284
Location
WA
First thing that comes to mind is replacement fuel pumps, many come with a black foam padding & zip ties to make up the difference in diameter from OEM $$$ to aftermarket $$. I've seen one break down & leave fragments/chunks in the inlet to the fuel filter as well as even finer fine black powder/grit around the final mesh filter surrounding fuel injectors. They can make a real mess.
 
Messages
1,467
Location
Maryland USA
Originally Posted by Auae85
I don't think it's charcoal from the evap canister because it doesn't break down when I rub it between my fingers, and charcoal would leave a smear / stain on my fingers. I don't think that it's sugar or other granular fine put in it due to vandalism, because he has a locking fuel door.
You are thinking of charcoal , as in a charcoal bbq fire ? Activated carbon could be very hard and not leave any obvious smears. It all depends on what it was made from originally- it could have been processed out of coal. What I am saying is that you should not rule out activated carbon at this stage. Its also possible that the finer grains of crud could be affecting the injectors.
 

wog

Messages
247
Location
massachusetts
My wife f150,was doing the samething,dealer took tank out after 4 trips in and found same grit. They couldn t figure it outas to what it was,wife s work lab said it seem to be carbon of some sort. No one can figure how it got in there. Insurance company paid claim of vandalism,cause dealer said it was put in tank.
 
Messages
77
Location
AL
Thread starter
Anyone know how I can get the fuel pump to run without cranking? I tried jumpering EFI relay connections in the fuse box near the battery. Having ignition "on" made no difference. I just want to pump straight from the tank, to the inlet side of the filter, where I have a hose going into a bucket.
 
Top