Need Expert advice for 308 GT4 Fuel Tank Assembly

All,
As many of you know I am doing a major plus on my GT4, and ran into a problem. I took out the float assembly on my left driver side fuel tank to paint my tanks and for the life of me cannot figure out how it goes back in correctly.

It seems obvious that the arm goes in the middle baffle, (and there is even a swing mark there, however I was almost sure it went in the baffle to the right. The right baffle however has a shelf that wont allow the float to rise above half the tank which makes no sense as the float mechanism has a stop that lets it rise to about the top of the tank. I have lots of pics on how the top sender unit plate is affixed to the tank and in both locations I cant hear the arm swinging.

I am wondering if the tank cinched in the car and full of fuel may expand just enough to make the float swing easier.

has anyone done this or knows how it goes any help is appreciated!
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IIRC, I bent the float arm. Then installed it halfway, straightened the arm and then installed the rest of the way. I will have to think about it. It also took a couple of tries to get it to move smoothly through the whole range. This would be good thing to check with an ohmeter before and after installing.

Jay

 

I checked it and got .34k ohm at the bottom and OL at all other points????? It was working (well if you consider any Ferrari fuel gauge working) when I took it out????

BTW I did not bend the arm but may do so a tad to get it right once i figure out where it goes!!!!

 

Dear Friends,

I spent half the day messing with the float arm. I bent it quite a bit so that it would move, attached a string to the end to see if I could move it up and down. As it was originally when i turned the tank upside down no movement whatsoever. After bending the arm a bit, when I turn the tank upside down you can hear it slowly slide up likes its rubbing on something eh eh, eh eh, eh eh, but when i turn the tank right side up the arm falls down quickly, clank?? Do you think that when strapped in and full the shape of the tank may deform allowing greater movement???? Do you think it had preloaded friction on it so that it would not misread(which it always did by swinging widely anyway)???

I just cant put this back until I get this straight as it took me from sept to get this far and I dont want to take this tank out again................

Thanks in Advance

 

I can't advise as to whether the tank will change shape when full but I wouldn't expect much change.

It looks like the sending unit might be bad as resistance should change in a more or less linear fashion from empty to full.

Full should have the lowest resistance (0 ohms).

 

Rob, it might... but I wouldn't count on that as it will be minimal at BEST and then what happens when the tank is empty...

In your picture, the baffle seems to be angled. Is that normal? Is it loose? With the sender out, if you shake the tank does anything sound like its moving? You have my number... call if you want to chat about it.

Rick

 

I've been battling this problem for decades. Even installed a new sensor unit years ago, but didn't get it right - it hangs up at 1/4 tank. But I do have an old sensor that I've taken apart and analyzed. I measure the following:

8/8 20 Ohms
7/8 35 Ohms
6/8 60 Ohms
5/8 90 Ohms
1/2 125 Ohms
3/8 160 Ohms
2/8 200 Ohms
1/8 250 Ohms (short)
0/8 300 Ohms (short)

The last two readings are overridden by a set of contacts in the sensor that shorts out, which causes the low fuel light to illuminate.

Others have measured the resistances at 44.5 Ohms at Full; 276 Ohms just before the light comes on and 376 Ohms at Empty.

I did some research some years ago and found a patent for a fuel level sensor which doesn't use an arm, but a tube filled with a series of reed relays and resistors, and a float with magnets on it to close selected reed relays. I've got a box with the reed relays, the resistors, a glass tube, etc. sitting on my workbench, but its a back-burner project. When I do complete it I'll post the design and procedure.

 

how do yoy hook up the meter I just put one contact on each i noticed the car setup has a ground wire. I am getting .36K at rest and OL.....1.3435......2.3737....OL etc.

Rob

No loose baffles, can any of you GT4 guys remember which baffle it went into I can only imagine the one without the shelf???. BTW it was working before I took it out?

 

Well Dear Friends,

I don know where to start, after 3 days. I am not sure I figured it out, but hope I did the right thing. It made no sense for the float to be in a chamber that only went half way, unless that is the way ENZO wanted it, so I messed with the float and arm until I got it to move up and down without any resistance in the large baffle that went all the way from the bottom to the top of the tank.

I never could get any OHM readings off it that made sense to me but on DCV on the meter it started out at .1 and went to 199.00? Since I am not an electrical expert Ill let you guys figure that one out. News is that part is NLA, but they send a generic one that you have to cut and or bend the arm (who would have guessed). I also noticed that I am pretty sure after taking the thing in and out 100 times that it can be removed with the tank in place.

Now here is my problem:

I got the tank back in pretty easy but when I went to connect the "L" bolt to the chassis at the bottom of the strap, it would not reach. I checked my before photos and it had originally on a few threads (3) with no washer OEM. On the other tank it had 13 threads exposed but when i re-assembled it I could only get a few in before I tightened it up to 13. So I have figured out that unless I come up with a solution, This 3" long "L" bolt will not work. I tried several ways of trying to get it through and got within 1/16 of an inch to the hole but I need another 1/2". I also noticed that the tank did not have a pad on the lower firewall side like the right one. So I am thinking when the car was assembled the strap and bolt were not long enough so no pad and 4 italian guys stronger than me got it through.

If anyone has any suggestions let me know. Im sure I could rig something up but the fuel tank seems critical to me so I'm not sure I want to jury rig it. If I could get a 3.5 to 4" "L" bolt I would put an extra pad on the bottom (where it is and has been rubbing on the firewall since birth), but where am I going to find an4" long 8mm "L" bolt with a cotter pin hole!!!

Any suggestions would be great. here are some pics.

Thanks for responding! I should not have yelled with glee like Alexander Hamilton did today when I put the tank in before tying it down. It not over until........

you pal Rob
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I recall when I put the tanks back in my GTS, it was a PITA to get the nut started on the strap bolt. The tank has to be in just the right place and I needed a friend to push hard on the tank to make the straps reach. The last photo looks familiar -- on my first attempt to fit the tank, the bolt appeared to be way too short. After a bit of futzing, the tank settled in and the bolt got closer, but it still required pushing by another set of hands.

 

I contemplated one of those, for the bow tank of my boat, where the pounding insures a short life span of the conventional sender....real expensive tho......

You could always go with a tube sight glass, as I saw on a Harley yesterday....

 

I don't remember exactly what I did to get mine back in with the strap, but I recall using one of those ratchet strap tie-downs some how to get it all back in.

Can't help with the fuel sender. I've taken my fuel sender in and out several times and it was easy enough I don't have any mental notes on which way, etc.

EDIT - I found a picture of my sender removed. It doesn't seem to have any bends in it at all. The bends might be your issue.
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Dear Friends,

I gave up on the original bolt and had a good friend make an extension. I swear It needed it. I also had to spend hours bending the float mechanisms until it moved freely inside the baffle that goes from the top to the bottom of the tank. Here are some pictures of my before and after tank. Things are going slowly!

Today Gerald Roush died, earlier in the week Ronnie James Dio....

Rob
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