View Full Version : How to clean out my fuel tank?
I dropped my tank today to check for contamination, and as I suspected, there are little black specks in the tank. My fuel pump was almost completely clogged at the screen with black junk from the fuel lines. I've got all the fuel out of the tank, but how should I go about getting it cleaned out so I don't suck this stuff into a new pump?
I'm curious how your tank became contaminated. Bad gas?
Wrong fuel hose is my guess.
Gordon Levy
03-26-2022, 05:52 PM
My bet is the float from the fuel sending unit is disintegrating. Seen this a few times.
Thanks, Gordon. I'll check that while I have access.
Here is what I see after pulling the pump and looking in the tank.
This is what got through the pump's filter:
https://thefactoryfiveforum.com/attachment.php?attachmentid=164576&d=1648335194
The inlet to the pump was almost completely plugged.
https://thefactoryfiveforum.com/attachment.php?attachmentid=164577&d=1648335194
https://thefactoryfiveforum.com/attachment.php?attachmentid=164579&d=1648335194
Nigel Allen
03-26-2022, 05:58 PM
I am currently helping a friend over here that has a Mk3 with exactly the same description of contamination in the tank.
The first we knew about it is when the engine (LS3) started running poorly and misfiring. Checking the fuel pressure gauge revealed a low pressure as the engine load increased. We removed the fuel pump and were surprised to find the inlet filter completely clogged with small black granules, with more also rolling around in the bottom of the tank. It is a requirement over here that vehicles are fitted with a charcoal canister. The canister fitted to this particular car was removed from a scrapped vehicle. My friend assumed this is where the black granules are coming from but I'm not convinced. Regardless, we have now fitted a fuel filter between the line to the charcoal filter / tank to capture any potential contaminates.
We have washed out the tank and are at the stage of being ready to refit it.
I would describe the granules as black in colour and about ~0.5 mm in diameter. There was at least a hundred in the tank. Is this what you are seeing? Did you fit a charcoal canister?
Edit: I hadn't seen your later post when I replied. Your photos exactly show the conditions that we are experiencing.
Regards, Nigel
I am currently helping a friend over here that has a Mk3 with exactly the same description of contamination in the tank.
The first we knew about it is when the engine (LS3) started running poorly and misfiring. Checking the fuel pressure gauge revealed a low pressure as the engine load increased. We removed the fuel pump and were surprised to find the inlet filter completely clogged with small black granules, with more also rolling around in the bottom of the tank. It is a requirement over here that vehicles are fitted with a charcoal canister. The canister fitted to this particular car was removed from a scrapped vehicle. My friend assumed this is where the black granules are coming from but I'm not convinced. Regardless, we have now fitted a fuel filter between the line to the charcoal filter / tank to capture any potential contaminates.
We have washed out the tank and are at the stage of being ready to refit it.
I would describe the granules as black in colour and about ~0.5 mm in diameter. There was at least a hundred in the tank. Is this what you are seeing? Did you fit a charcoal canister?
Edit: I hadn't seen your later post when I replied. Your photos exactly show the conditions that we are experiencing.
Regards, Nigel
Nigel,
Yes, very small black granules clogging the pump and floating in the tank. I do not have a charcoal canister on my car.
Dave
Nigel Allen
03-26-2022, 06:09 PM
As for cleaning the tank, we just washed it out with a high pressure cleaner then used a blower to dry out the tank whilst leaving it in the sun for a few days.
A good tip; do not be tempted to use a vacuum cleaner to suck the contamination out. Some guys in my town used a shop vac on a boat fuel tank that had scale in the bottom. Promptly the vacuum cleaner exploded as a result of sucking fumes past the brushes on the motor. After a huge explosion and air filled with the contents of the vacuum cleaner bag, all that was left was the power cord.
Wife was not happy, but at least they got front page of the local paper!
J R Jones
03-26-2022, 06:10 PM
EEPP, you must have a return line to the tank, otherwise the fuel is out only. There COULD be a debris source feeding the return line.
I have done a lot of fuel tank work and the fumes are THE hazard. I never work on a tank until it has spent overnight with an air line or fan blowing through it. There can be NO fuel odor.
My recent contamination was a Toyota MR2 from NC where it was likely vandalized. The tank is in a tunnel between the seats and is a BIG job to remove. I drained and flushed it with gas from filler to drain plug. I still had flow issues and pump noise after 15-20 miles. After sitting it was OK for another 10 miles.
I pulled the tank to find red silt in the tank sump, between a half and one cup. With a year or more stored like that, I had to pressure wash the silt free and out the drain hole. I sprayed into every orifice and panel mount then a fan-dry overnight before reassembly. Obviously new pump, strainer and filter.
If you do not have a drain in the tank, you may have to vacuum the crap out, but dry it out first, a vacuum can ignite fumes.
jim
I'm tempted to just buy a replacement tank since they are only about $100. With several thousand invested in the new stacks, it may be the best answer to avoid any chance of creating issues with the new setup.
Nigel Allen
03-26-2022, 06:20 PM
Nigel,
Yes, very small black granules clogging the pump and floating in the tank. I do not have a charcoal canister on my car.
Dave
My guess is that there is a gasket or sealant between the tank halves that is deteriorating or contamination from manufacturing process. It took 6000k's and 2 years for it to cause issues.
There has been a bit of talk on the forum lately of ethanol damaging fuel lines. In our case this is not a probable cause as we do not run ethanol in this vehicle.
Gordon Levy
03-26-2022, 06:23 PM
When you put your stacks in did you use braided lines? what did you cut them with? did you clean them before installing the?
When you put your stacks in did you use braided lines? what did you cut them with? did you clean them before installing the?
I haven't installed the stacks yet. I used Fagola fuel hose, but not the PTFE lined type. I used a cutoff wheel to cut the lines and blew them out with compressed air before putting the fittings on. They've been on the car for over two years and it ran fine for all but the last six months or so. I started having issues last summer.
Gordon Levy
03-26-2022, 06:43 PM
OK, back to my original opinion.
Derald Rice
03-26-2022, 07:29 PM
I have used a Gas Tank sealer from Bill Hirsch, it is primarily used to encapsulate rust in aviation applications.
No idea if it would help with what looks like deteriorated rubber
Application was to get the tank clean and dry, then slosh it around in the tank to cover the inner metal, then let
it drain and dry overnight....It took a quart to do a 12 ? gallon tank.
It worked well on a 34 Ford, but since our tanks are very cheap ( and clean ), that is the direction I would go.
https://www.hirschauto.com/ALCOHOL-RESISTANT-GAS-TANK-SEALER/productinfo/GTS/QUART/
Pictures of the sending unit float. It looks fine to me and didn't leave any smudges on the paper towel when I wiped it off.
https://thefactoryfiveforum.com/attachment.php?attachmentid=164591&d=1648340977
https://thefactoryfiveforum.com/attachment.php?attachmentid=164592&d=1648340977
https://thefactoryfiveforum.com/attachment.php?attachmentid=164593&d=1648340977
I just ordered a new tank that will be here Thursday for $100. Sending unit looks okay unless someone sees something in the pictures that I'm not seeing.
GoDadGo
03-26-2022, 08:41 PM
Papa Dave,
I would bet big bucks you running fuel that contains up to 10% ethanol.
That crap tears up and eats up all sorts of stuff in most fuel systems.
Do you have any options of finding 100% gasoline in your area?
Steve
Papa Dave,
I would bet big bucks you running fuel that contains up to 10% ethanol.
That crap tears up and eats up all sorts of stuff in most fuel systems.
Do you have any options of finding 100% gasoline in your area?
Steve
Steve,
We're starting to see some stations offer ethanol-free gas, but it's not very common across the state.
Dave
GoDadGo
03-26-2022, 09:02 PM
Steve,
We're starting to see some stations offer ethanol-free gas, but it's not very common across the state.
Dave
Any chance to get 100-LL at your local airport?
They let us fill gas cans as long as we tell them we have an Air Boat with a Lycoming Engine.
Off the record, they've let me pump straight into the tank when I showed up in the Cobra.
That stuff really last a long time, but I do mix it with Outboard Lube at 150 to 1.
Good Luck & Happy Motoring Papa Dave!
Any chance to get 100-LL at your local airport?
They let us fill gas cans as long as we tell them we have an Air Boat with a Lycoming Engine.
Off the record, they've let me pump straight into the tank when I showed up in the Cobra.
That stuff really last a long time, but I do mix it with Outboard Lube at 150 to 1.
Good Luck & Happy Motoring Papa Dave!
No idea, Steve. We do have access to race fuel, but nothing convenient. I just need to eliminate any components in my fuel system that can deteriorate with our mandated fuel mixtures. I'll be doing hard lines and PTFE-lined flex lines on the connections at the tank and fuel rails. A serviceable filter that I can open and replace the element and inspect for potential issues.
GoDadGo
03-26-2022, 09:32 PM
Could A Marine Fuel Filter Possibly Work?
https://www.westmarine.com/fuel-filters
I know, I live in the swamp where it floods often.
Could A Marine Fuel Filter Possibly Work?
https://www.westmarine.com/fuel-filters
I know, I live in the swamp where it floods often.
Jim Inglese recommended a 10 micron post-pump filter and the pre-filter is essentially limited to what comes with the pump. You can do more filter options with an external pump, but that has it's own set of challenges. I really think my fundamental error was going with non-PTFE lined hoses. Once I get the old stuff off the car, I'll do a destructive analysis (there's the satellite system engineer in me) and see of I can identify the root cause. The most imortant thing to me right now is ensuring I have a clean fuel system to start with when the stacks get installed.
GoDadGo
03-26-2022, 10:16 PM
Can't wait to see your car sporting the new induction set up.
Good luck and watch your pinkies.
I cut open my fuel lines and don't see any degradation that would account for the crud in my fuel system. So, the only thing I can think of is that I must have gotten some bad gas someplace. It would have taken quite some time to accumulate all that crud at the inlet of the pump, so who knows when it may have happened? In any case, I'll have everything clean and fresh soon.
Geoff H
03-27-2022, 04:15 PM
Might be nothing - when I changed my fuel pump a few years back I also changed the hose that connects the pump to the pressure line. I was going to use some hose I had on hand, but learned I needed hose that was fuel submersible as regular hose would degrade/break down. Not sure what was involved with your original fuel pump hanger assembly but it would be quick and easy to rule it out with it all apart.
Geoff