No gas from fuel tank

[Rhinkel]

hey all: New to Mercedes but not new to cars.  I'm putting together  a 70   280 sl that my dad had an engine fire on while restoring it. He just shut the hood and left it for years. I have it now and fixed all the under hood items, now I'm on the fuel system. The fuel tank was lined ten years ago and it had fuel delivery problems then...long story but that's what led to the fire. I went to turn it over just to see what would happen and there was no fuel delivey. Could tell by the smell. The pump was warm and I confirmed current to the pump. I pinched off the line from the tank to the pump and then hooked it up in anticipation of fuel coming out and draining it. The small line had fuel come out, the larger one just dripped. When I un-pinched the larger line, hardly a drip came out. I have new lines coming now and a new in tank filter. I'm am curious about the lack of gas flow. Shouldn't gas pour from this line?  Does it pass thru the in tank filter first which might be all clogged up? Can't wait to get all the parts and see if she fires up. Happy 4 th! Appreciate any and all comments

[Tyler S]

There is most likely sludge and/or rust in the bottom of the tank from old fuel. You can remove the large drain plug on the bottom which also houses a filter screen. There may also be issues with the fuel pickup tube in the tank being plugged from the previous re-lining attempt. Compressed air and a stiff wire may help unplug it. Be prepared  for the possibility of having to replace the tank.

[Rhinkel]

A stiff wire inserted through the fuel out let into the tank?

[Tyler S]

Yes, others here have used a guitar string to do this.
Sometimes when the tank is re-lined the coating gets into these lines. Its difficult to remove as the lines are part of a structure inside the tank nicknamed the "flower pot".
See link.
http://www.sl113.org/wiki/Fuel/Tank

Also make sure you are using more than 1 gallon of fuel when verifying if the line is plugged. The tube is above the bottom of the tank at certain points and wont prime without a good amount of fuel in the tank.

[Rhinkel]

All I can say is WOW! In all my 30 plus years of hot rodding, many cars, restorations of 60's Chevy iron, I have NEVER, EVER, seen a tank as jacked up, gummed up and clogged as this one. AND IT WAS BOILED OUT AND COATED 10 years ago!

I'm ordering a new Benz tank, no re-pros- had enough trouble with re-pro stuff and my Chevys..... Unless someone has experienced otherwise with a tank. Please let me know.

Hence, I' ve found my fuel delivery problem!

Cheers to a new fuel system.

[mbpaul]

Your fuel tank problem sounds like the one I had on my 230SL about 4 years ago.  I tried everything I could think of the get the old tank to work because the tank did not leak and the exterior of the tank showed no rust whatsoever.  Sure hated to pay the big price for a new tank but it made all the difference in the world.  Car has run great ever since I replaced the tank.

I still have the old tank and I have resisted to throwing it away. It looks great on the outside.  I would give it to somebody for shipping cost only if they thought they could get it to work again.

[Tyler S]

Rhinkel, Probably wouldn't be a bad idea to remove the bottom cover plate on the pump as well. May have similar issues if it was left plumbed into the system for all that time.

[Shvegel]

New tank is a good idea.  Injection pumps are prone to getting damaged by tiny rust particles.  Sort of like throwing sand down your intake.

[Jordan]

Sounds like my fuel tank as well when I purchased the car in '09.  Replaced the tank and the pump and have never had a fuel delivery issue since.

Rhinkel, you may also want to clean the filter on your electric fuel pump as it is probably gummed up with crap as well, as it filters anything coming from the tank.  Will save you the cost of a new pump in the long  once you have your new tank installed.

[Rhinkel]

Thanks for the comments. I've ordered new lines thru mercedes source- including under the hood. I removed the pump and it's stuck. Fortunately I have a back up one in the parts pile that works. I'll flush out the line leading to the fuel filter, change the fuel filter and also install a filter between tank and pump to be able to see the flow. This beautiful little car never ran right and I can see why.

On another note, a Benz tank is about 1 k. There are shops that cut open the tank, blast it inside, coat it and re weld and paint the tank. Has anyone tried this level of restoration successfully? It'll run about $350.

Thanks, Rob

[Pinder]

before you throw the towel in on that tank its likely that its varnish due to fuel sitting rather than rust. you can clean it out and the  one possible way is to cut an access flap on top of the tank (avoid cutting the vent lines)  a cutout of approx 7x12 inches will allow you to reach in and clear it spotless. you can then use POR 15 tank sealer or just use the metal ready spray. Once you do that you can seal the tank back up. you can use self tap screws and another peice of sheet steel. use tank seaker to form a gasket. aftwerward you can use more tank sealer around the cutout joint for a 100% complete seal. once the tank is installed the cutout is hidden. but if you have the budget a new tank is the way to go.

  to cut the tank make sure its totally filled with water and you have rinsed it out several times. its pretty easy to cut open with tins snips and a pilot hole to start the cutting. it should take you about 10 mins to cut the access hole.

[Pinder]

I used a filter  from tank to pump and its a high flow filter from Fram G3. works really good. dont use the small glass ones they are too restrictive.
Also if you have your original fuel pump it has a filter in there too. clean it out.

[Pinder]

See picks on how its done. As a final step i used body filler to cover the cut areas to be sure of an airtight seal

[Rhinkel]

Thank you! Another great idea!

[Rhinkel]

As it turned out, I ended up having the fuel tank opened, sandblasted, coated and put back together. The welds were done well and grinded flat and you can hardly tell. The tank was previously coated- note to all- NEVER HAVE YOUR TANK COATED AND THEN BAKED !! The flower pot was melted. As part of the repairs I made, the flower pot was remade with steel, welded in, the tank coated and baked.

My real question though, the tank had insulation on it to prevent squeaks. I neglected to take picture and don't know if there is anyone who knows where to get the replacement insulation and the placement of it. All help appreciated! Thanks Rob

[Pinder]

you did the right thing. the only way i got both my tanks working perfectly was to open them up. I may have pcis of my tanks with insulation in place. let me see if I can find the pics.

[Pinder]

This is the best pic i have shows most of the insulation

[mdsalemi]

OK, I know that fuel tanks--OEM or the repro ones--are expensive. But, I'm reading about a lot of very laborious, intensive work, what with removing, cutting, welding, repairing, making a flower pot out of steel, coating--is this really saving anything?

[Pinder]

I think each person has to judge if its worth the effort and if the budget fits. In my case I had two tanks to fix. the thought of spending $3000 on new tanks or fixing it over a weekend made sense for me and my flower pots were not damaged. I also learned a lot in the process and enjoy bring old things back to life. Its a hobby for me so my personal time I do not count into the cost as I enjoy the journey. I also am on a limited budget with two kids and a wife that can count to infinite in shoes and handbags so if i can save $2 to $3000 I try and do that. My total material cost was probably $30 to fix both tanks. Its not for everyone to do at home its labor intensive but not difficult to do but there is satisfaction in it and also in opening up the tank you get to learn how the internals work.

The work to drop and install the tanks is the same if you recondition or replace.

Regards

 Pinder

[Rhinkel]

Thank you very much for the pics. I spent close to $600 for my repairs. Well worth the cost versus the agony of tracking down fuel problems that have plagued this beautiful car. A new tank would be over $1000 and no guarantee it would fit perfectly. This rebuilding of this one is now better, solves the fuel delivery problems and should last for the rest of the life of the car. I am rather new to the w113 world but have lots of years spent as a gear head. Getting fuel delivery perfect, the ignition perfect are key to weeding out issues. Basics first, makes it easier to find the other stuff if not working correctly.

[Tyler S]

I also am on a limited budget with two kids and a wife that can count to infinite in shoes and handbags so if i can save $2 to $3000 I try and do that.

I feel your pain. This month I am investing in leather. The question is which kind. Louis Vuitton, or Dash and Door Panel.

[Pinder]

the door panels and dash a is a solid  investment;  Louis Vuitton is insurance that you get to work on your car in peace and quite.

[ja17]

Yes these tanks are quite complex.  With sediment in your tank, you can remove the drain plug and no or very little fuel may drain, even though your tank has a lot of gas in it. The entrance to the "flower pot" gets plugged and the fuel in the tank cannot drain out!  Quite confusing to the in-experienced. Also do not forget to clean the electric fuel pump intake screen inside the intake fitting of the electric fuel pumps. These electric fuel pumps are gravity fed fuel, so make sure your electric fuel pump is hung correctly low so fuel will flow down to it.

[Pinder]

I rebuilt my existing fuel pump and saving it for the future. I replaced it with a new carter pump recommended on this site. it works very well. the carter pump does not have a filter in it so i put an inline filter that can be inspected easily. Since my tank cleanout everything is running very well. I was able to mount the carter pump and put the shield on the car. the inlet is slightly higher but is within specs of the carter pump.