Gas Tank Problem? (Already searched) Please read...

[Jayru]

Ok, so i'm driving yesterday and the car stalls out. My sender doesn't work, so i think i'm out of gass. I pop the hood and the filters bone dry.

Fill it up with some gass (2-3 gal) and still nothing. So i disconect the hose from the fuel line and stick it in the gas can, bam, starts right up.

So i know what Carl will say, clogged lines/rust in the tank. Nope! I drop the tank today and their is No Rust inside the thing, just a small amount of what looks like setiment(SP?),dirt, ect. I blow air through the lines and their clean as a wissle.

So what the hell is going on here? Could it be the mistery fuel hose air sucking thing as seen here:

http://www.classiczcars.com/forums/showthread.php?t=16353

The only thing odd i see is the PO seems to have eliminated GF-21 on the diagram below. He disconected the hose and filled the tank nipple with some type of resin. Could that be a problem? All the other vent hoses are attached.

The car had about 5 gal of gas in it when i drained it.

240z gas tank.bmp

[Bambikiller240]

You are right. I'll be telling you the same thing as before. the pump sucks, the crud, (sediment) gets sucked into (or over the opening to the lines) and plugs them up. when the sucking stops the sediment can (but not necessarily "will") fall away. BTW, there should be NO sediment in the tank. Do yourself a favor and clean it out.

It should be obvious by now that something is preventing fuel from getting to your filters. Since the tank and lines are the only things "upstream" something must be blocking the fuel from following those lines to the filter.

If you think it's the GF-21 (missing) hose that's the cause (I don't), remove the plug, buy 3-4 ft of hose and reinstall it.

Come on Jayru, this isn't rocket science, it's common sense.

[Jayru]

Carl, are you lisening to what i'm saying? The last time you told me it was rust/crud it was my alternator, what will it end up being this time?

The lines are clean, as well as the tank, except for the most minute amount of dirt. My fuel filter has been clean since i started driving this thing (after i swapped out the original one).

If their was all this crud in there like you always suggest (Blocking my lines), my filter would be filled with the stuff, which it is Not.

I will have the tank cleaned (since it's already out) But i don't think that (since it's almost clean already) is my problem here.

[Bambikiller240]

Not necessarily true, it only take a small bit of crud to plug that small diameter line. HOW MUCH DO YOU THINK IT TAKE TO PLUG THAT LINE?

If I'm was so wrong why are you still having problems with keeping the car running? I submit that you didn't fix the original problem, you "fixed" something else, IF ANYTHING.

If you are so smart about this car what do you suggest is the problem and why are you asking for help?

You ask for answers and yet when advice is given you find 50 excuses why the advice can't be correct.

YOU TELL ME WHAT COULD KEEP FUEL FROM GETTING TO THE FILTERS (WHEN YOU CLAIM YOUR PUMP WORKS) BESIDES THE LINES BEING OBSTRUCTED!

EDIT: Jayru, I am only trying to help you. I have owned 3 240Z's and worked on them ( and those of my friends) for 30+ years. What I am telling you is one of the most common issues with the fuel system on a car that has sat unused for any length of time, like yours. I've seen it my self at least a dozen times, and heard from others here and on other websites of many more instances.

Are you sure that all of the other vent hoses are not obstructed by resin like you mentioned for GF21?

[Brett240]

Jayru,

check the lines running to and from your tank (the ones that hook up to the metal lines at the back)

check out ok? no cracks?

leave the ends that hook up to the tank disconncted. now disconnect the hose ends that hook up to the metal lines in the engine bay. blow throw them and have someone check the other end.

if you cant feel the air blowing out then you line is clogged and you need to clean then by running compressed air through them. now would be the time to make sure there is a filter BEFORE then metal lines.

CHeck to make sure the tank end nipples are clear, you said this was ok already sooo

hook it all back up, you should be clear up to the rail. now pull the line the exists your pump (mechanical right???) and crank the engine over (oh by the way put the end of the line into a container...)

fuel coming out?

etc etc etc just keep checking along the line until you find the block.

[Jayru]

I understand Carl, it just seems you are always so quick to blame crud in the tank for my problems. It wasn't the case before and it may not be now.

But i understand you are speaking from experience, i can only tell you what i can see here looking at the car, and their didn't seem to be any overwhelming ammount of dirt that could physically block anything. But then again i can't see all the way inside. I am going to find a place locally to clean the tank and then that particular piece of the puzzle will be solved.

Only the one vent line is blocked, and it doesn't appear i can unblock it (filled with resin). Mising this one vent offers no ill effects? Why are their so many in the first place? Wouldn't one (upper) vented to the filler neck simply solve the venting problem?

Brett,

Yes, that is what i have been doing and their has been no evidence of a clog. That's why i was wondering what else could be happening here (Some kind of vaccum or lack of because of the vent system not allowing fuel to be drawn into the lines, etc)

All lines are clear (Blew air through them) I can't tell if the hoses are cracked though. They are most definatly the original ones, so i will replace them all, clean the tank and hope it doesn't leave me stranded when the fuel level gets low again.

Thanks

[Bambikiller240]

I understand Carl, it just seems you are always so quick to blame crud in the tank for my problems. It wasn't the case before and it may not be now.

But i understand you are speaking from experience, i can only tell you what i can see here looking at the car, and their didn't seem to be any overwhelming ammount of dirt that could physically block anything. But then again i can't see all the way inside. I am going to find a place locally to clean the tank and then that particular piece of the puzzle will be solved.

Only the one vent line is blocked, and it doesn't appear i can unblock it (filled with resin). Mising this one vent offers no ill effects? Why are their so many in the first place? Wouldn't one (upper) vented to the filler neck simply solve the venting problem?

Yes, I am quick to point it out, because it's a very common problem to Z's in particular, and other cars as well. Also. keep in mind that from "here", I can't see what you can see "there" so you have an advantage that I don't have in that regard. All any of us can do is suggest things based on our experiences. We can't check it out for you, and we're going to be wrong sometimes. But hey, at least you didn't pay someone to give you the wrong (or right) advice.

As stated before, it doesn't take much to plug a line, and it may not be visable if it's stuck inside the line. It doesn't need to be an overwhelming about of crud, it's only about a 1/4" to 3/8" line (I know it's metric, but I'm estimating in common measurements used in the USA) Have you actually cut open the plastic filter housing so see what's inside of it? It's not always easy to view trapped stuff inside the filter from the outside.

I don't know why they used so many vents, but people (not me, yet) have successfully gone to just one of the upper vents, so I doubt that is the problem on your car.

There really isn't anything back there that can shut off the flow of fuel (no valves, etc). If there is a working vent (and if it's unobstructed, it is), and a free flowing supply & return pipe to transport the fuel to/from the engine bay, your pump should be able to draw the fuel to the filter, and return excess fuel to the tank (if the pump is in good order). It's about as simple of a system as can be.