280z fuel tank problem

[rzkas]

Hi and how are you? my 76 280z gas tank is bad. the pump cannot get fuel out of it to send up to the engine.

what should be my next step?

buy a new or used tank or clean up the tank?

if cleaning up the tank is the best and cheapest way to go, how do i go about cleaning the tank and the sending unit? after cleaning will i have to replace the sending unit with a new one?

pls give me ideas pls. i am a student and trying to restore this car. i work on it myself because i can't afford to have a mechanic to come work on it.

i am looking for the cheapest and reasonable way to fix my gas tank and have it working fine.

thanks

[Powderkeg]

Are your fuel lines clogged? Do you know the extent of the condition of the tank? How about the fuel pump?

If your tank is in decent condition you can recoat it yourself with a product like POR-15's tank renew kit (~$70.00).

If you do recoat the tank replace all of your fuel hoses and check the condition of the fuel filler hose as well.

New sending units are very expensive but can be had. Check Arizona Z Car, Z man of Washington, classifieds. etc.

This topic has been discussed recently and there is a nice write-upon this site. I just did my 76 tank about a month ago with POR-15 and it turned out really well. It took about a week. Also coat the fuel tank straps as they are hard to come by.

Good luck.

Dave Ruiz

[rzkas]

Are your fuel lines clogged? Do you know the extent of the condition of the tank? How about the fuel pump?

If your tank is in decent condition you can recoat it yourself with a product like POR-15's tank renew kit (~$70.00).

If you do recoat the tank replace all of your fuel hoses and check the condition of the fuel filler hose as well.

New sending units are very expensive but can be had. Check Arizona Z Car, Z man of Washington, classifieds. etc.

This topic has been discussed recently and there is a nice write-upon this site. I just did my 76 tank about a month ago with POR-15 and it turned out really well. It took about a week. Also coat the fuel tank straps as they are hard to come by.

Good luck.

Dave Ruiz

my fuel lines are ok and i dont know the interior condition of the tank but i know for sure my fuel pump cannot suck the gas out of it. it like something is blocking the d pipe where the gas suppose to come when the fuel pump draws or pull it. can i get step by step instructions on how to clean the gas tank and keep my sending unit in good working condition.

[IdahoKidd]

Sending units are a dime a dozen used. I bet I have at least 4 from various parts cars. First things first, pull the sending unit out of the tank (while still in the car) and have a look into the tank. You can see quite a bit with a flashlight looking in through the hole and even more with a remote camera. Look at the bottom of the tank and see how much crud might be in there. It there is a bunch, you'll have to drop the tank. If there isn't, try taking out the fuel pump and using air pressure, blow the line backwards into the tank (put the sending unit back in place to avoid a mess!)

How do you "know" the tank pickup is blocked and that it isn't a fuel pump not sucking?

If the tank is indeed bad, there are several things to do, the cheapest is to scour up a used tank. Determine for certain what you are up against and collectively we can find a direction/solution.

[FastWoman]

I just did my tank. It's pretty easy to remove and replace:

(1) Pull the right rear interior trim panel. I think to get to it you have to pull the rear panel over the tail lights, the ceiling panel where the dome lights are, and the right quarter window panel. You'll also have to temporarily unfasten the right gas strut.

(2) remove the shielding over the fuel/air separator.

(3) Unfasten the filler hose and vent hoses. Shove the vent hoses through their holes.

(4) Drain the tank via the plug on the bottom right of the tank.

(5) Remove the fuel lines from the bottom right of the tank.

(6) Remove the round inspection plate (2 screws) over the righthand side of the fuel tank in the hatch area. Unplug the sender unit.

(7) With the rear of the car on jack stands, loosen the nuts at the forward ends of the tank straps. Pull tank downwards slightly to dislodge it. Loosen nuts more, and remove the straps. Drop the tank onto your tummy, and have a friend pull it off of you and remove it from under the car. Your friend will also need to guide the filler tube safely through the hole and ensure that your vent hoses aren't hung up on anything.

(8) Remove the sender by tapping the retainer ring tabs with a hammer and screwdriver to turn it in the obvious direction. Carefully extract the sender unit and put in a safe place.

(9) Lean the tank somewhere outside, preferably in the sun, with the filler tube downwards. You want any remaining gas to evaporate. The fumes are heavier than air and will sink through the filler neck. When you can no longer smell gas in the tank, it's safe to work on it.

Peer inside with a flashlight to see what's going on. In my Z (a '78), there's a fuel sump in the middle of the tank about the size of a tall coffee can (but a bit skinnier). That's where your filter screen is. The bad news is that you can't service it. You'd have to take it to a radiator repair place, where they can cut the tank apart, remove the screen, clean it, remove rust from the tank, coat it, etc. I think I was quoted about $500, but my tank was pretty clean and didn't need it. I simply powerwashed it, rinsed it several times with acetone and B-12, dried it, cleaned the old paint and rust from the outside, and repainted.

If your screen is clogged, you might be able to blow it out using compressed air through the fuel outlet tube. That might also destroy the screen. Many people will tell you that you can use an acid wash to clean out the tank. That's true, but it's also going to eat up the fine screen. Then if you use POR-15 to coat the tank, be aware that it will clog the screen. That's not a problem if you've already eaten it up with acid, but you may need to install an inline pre-filter before the fuel pump.

You should replace all of your rubber lines when you reinstall. Be sure to use only fuel line, including on the big vent hoses. You can get large dia fuel line from a tractor supply or via mail order from Hampton Rubber in Hampton, VA. (You'll have to call Hampton Rubber for this. They don't usually send out mail-order supplies. They can also supply the rubber strips for your tank straps, cut to the size you specify, as well as all the hose clamps you need.) As far as I could tell, my filler hose was made of some rubber like neoprene and was in fine shape, even after 33 years. That was the only rubber I re-used.

Good luck with this job!

[rzkas]

Sending units are a dime a dozen used. I bet I have at least 4 from various parts cars. First things first, pull the sending unit out of the tank (while still in the car) and have a look into the tank. You can see quite a bit with a flashlight looking in through the hole and even more with a remote camera. Look at the bottom of the tank and see how much crud might be in there. It there is a bunch, you'll have to drop the tank. If there isn't, try taking out the fuel pump and using air pressure, blow the line backwards into the tank (put the sending unit back in place to avoid a mess!)

How do you "know" the tank pickup is blocked and that it isn't a fuel pump not sucking?

If the tank is indeed bad, there are several things to do, the cheapest is to scour up a used tank. Determine for certain what you are up against and collectively we can find a direction/solution.

i have replace the fuel pump but still is the same problem. i figure this out because when i used a longer fuel hose and connected to a portable gas tank, the fuel pump was pulling the gas and the car starts and stays running but when it hooked up to the fuel tank the car doesn't start. how do you take out the d sending unit when the tank is still on the car. how can i access the tank through the trunk?

[sblake01]

There's an inspection panel in the hatch area above the tank where the sending unit is.

[argniest]

Well before I install my new fuel injectors, there is something bothering me in the back of my mind. What if my fuel tank is all rusted out and mucked up? I found a few posts on the forum about being able to inspect the fuel tank by removing the fuel sending unit.

Im starting to think I need to do that before I do anything else. I mean what if that tank is all rusty and icky inside. The rest of the car would never run according to specs, if the tank is sending junk into the fuel system.

Can a noob Z owner pull this inspection panel, and fuel sending unit without causing major problems. I am hoping its doable.

I am getting more famliar with my z car over this winter time. I just dont know why I would bother doing anything else until I know for sure if my fuel tank is in good/great shape or not. I mean if its in bad shape, then I need to fix it now. And that would set me back a while. But seems like the right thing to do.

Of course not knowing the history of the car, means it could have sat for a long time. Considering the tires all were flat spotted, makes me think it sat for a while. Meanwhile yukking up the fuel tank.

Edit: can anyone give me the steps to do this carefully and then I can look into the fuel tank. I have seen inspection cameras for like 150 bucks (of course they are not meant to submerge in gas so I wont do that). I would use up most of the gas, and then I could really inspect it good.

Edited January 30, 2011 by argniest

[FastWoman]

Argneist, you must be richer than Midas! You don't need a $150 inspection camera!

Yes, you can inspect your tank. First use most of your gas up. Then drain the remainder of your tank via the drain plug on the bottom. Inspect the drained gas for debris. Pull the inspection cover to reveal the fuel level sender. Unplug the sender. Gently tap the retaining ring with a screwdriver and hammer to rotate it. Note the orientation and how the notches line up. Then gently pull the sender out. Shine a small flashlight through the hole. Use a small mechanic's mirror or dental mirror to peer around inside the tank.

Debris from the tank won't hurt your injectors; however, it will clog up the intake screen on the intake. If it somehow makes it past the intake screen, it could harm your fuel pump. However, any debris will be captured by your fuel filter before it could make it to your injectors. The fine, soot-like debris from deteriorated rubber hoses has probably coated the inside of your tank. I'm certain it makes it past the intake screen, does not harm the fuel pump, and mostly gets lodged in the fuel filter, but I suspect some of it passes through the fuel filter and reaches the injectors. I suspect this would slowly diminish injector performance, so it would make sense to replace fuel hoses.

[argniest]

Thanks for the information. All good to know. So the intake screen is the first line of defense for any debris that would come from the bottom sluge possibly in the fuel tank. I would feel a lot better if I knew the condition of the inside of my tank!!!!!

If I totally drain the gas out of it....I heard that it can be hard to start it????? Any comments about that?

And one other thing, I am curious if anyone has ever put together a parts list for all the rubber hoses on the car? I would like to replace all of them this year, and preferrably before I install my new fuel injectors. Maybe that is just overkill to replace all of them. But seeing as most of them are probably really old, it seems to make sense.

I have replaced some of them for specific reasons. But thats only a few so far

Edited January 31, 2011 by argniest

[argniest]

Well here is what my fuel filter looked like. I have suspected the gas tank was probably rusty. Doesnt this prove it???

I have never cut open a fuel filter before, but I was shocked to see all this junk fall out of it when I opened it up

[sublime167]

Sorry to jack the OPs thread but, @FastWoman, if I was to remove the filter screen from the sump to coat the tank with POR15, and added one of the Fram inline filters before the pump would I be ok or should I avoid removing the screen. Also, would it be possible to remove the screen without cutting the tank open?