Here's 1 answer (well, enlargement anyway), and 2 queries.
My level gauge wasn't working - well, if watched carefully at switch on, it
flicked up away from the bottom, but nowhere near full, which is what it
was. Out with the sender unit.
This is a 1 1/2" dia alloy tube, ~14" long. Plastic cup thingy on the
bottom, held on with small nut (~2mm thread). Is that rust I see before me?
No, just congealed old gasoline stuff - chipped it off, undid nut. The cup
thingy has 1/4" of more congealed hard brittle crud in it - clean this out.
Next there is another nut holding a plastic cap in the end of the tube.
After chipping away more crud, get the nut off, and after a bit of a
struggle the plastic cap comes off. It engages the end of the fuel return
pipe also. There is a rod going the full length of the tubing. It has a
fitting on the end with 3 fine wires going to the far end, matching the
three electrical connectors on the top. The float assy should slide on this
central rod, changing the signal to the gauge head as it moves on the
wires - not mine! The central rod had some of the congealed stuff on the
bottom couple of inches, as did the fuel return tube. I couldn't remove the
outer alloy tube from the top plate - seemed to be pressed into it somehow,
so I had to carefully dislodge as much crud as I could with a thin long
screwdriver, shaking it out as I went, a bit of WD40 now and again, and
eventually the float would move with only the help of gravity. Reassembled,
and we have a gas gauge again. I guess if any of the fine wires are
disconnected, the unit is toast, but otherwise a good clean would seem to
fix it. It would have been nice to wash it in something that would dissolve
the crud, but I didn't have anything handy. I think I will replace the fuel
filter pretty soon too.
From all the talk of tank screens , do I wait until there isn't much in the
tank, and get one hand through the hole and go fishing for this screen? How
is it fixed inside the tank - it obviously can be removed through the top
hole? Metal or plastic? Folds/scrunches up to come out? Cant visualize it
yet.
Now - hot air all the time in the side vents - looking for the hot water
valve - under the air box ? Got the 2 bolts at the ends inside the box, but
where is the other fixing? I can see a small hex socket screw of some sort
diagonally down the center cavity in the box, but cant see how to release
the center of the box from the air measuring plate body?
Relays - are most/all standard types- any Bosch/Hella will do? -This is a
CIS 83 Euro, so no specials for EFI stuff here.
Thanks
JP
-----Original Message-----
From: Dan [mailto:dbrindle@kondratyev.com]
Sent: Sunday, March 04, 2001 7:11 AM
To: 928
Subject: [928] Re: Fuel Sender removal
John,
Looks like everyone is working on gas tanks this weekend. Mine is out but
I
spent most of the day cleaning it up for installation.
There is a special tool to remove the big ring. I use large channel locks
and just twist. The unit itself is held in by a rubber gasket and can be
pried out without much trouble. There is a cup on the end of the sending
unit that can catch on the baffle but this is just a matter of shifting the
unit back and forth. The baffle is spot welded to the bottom of the
tank
and can come loose. If this happens then ten to one the tank screen is
busted too.
Shake the sending unit - the light connection can come undone and will
rattle around inside. The unit is held together with a nut on the bottom.
I can be taken apart and inspected and repaired. Check the filler tube for
old gas or corrosion.
Dan B.
-----Original Message-----
From: John Eifert [mailto:JohnEifert@hotmail.com]
Sent: Saturday, March 03, 2001 3:37 PM
To: 928
Subject: [928] Re: Fuel Sender removal
How did you get the big black nut off? I have a spare sender that haven't
installed yet. Looked at it today but decided to put it off till tomorrow
and finish the interior 1/4 panel replacement after seeing that thing.
JE
1983 928S US AT x 2
928OC
PCA
Gully wrote:
Hi, On my 87 S4 I'm trying to diagnose the level sensor. Currently trying to
remove the sender unit out of the tank. I have removed the big black
nut but it still will not come out. I have been able to lift it up about 1/2
inch but it seems to be contained by something else.
Any ideas? and solutions.
======
Finally got it out, the cup on the bottom of the sender unit was getting
caught on the baffle hole in the middle of the tank. A word of warning!, if
you are trying to diagnose a problem with the fuel gauge and reserve warning
light, my last resort would be to remove the sensor unit.
My sender turned out to be fine and now i need to tackle the gauge
calibration.
Trying to get the nut back on the fuel tank was a real pain in the butt, the
sender does not sit parallel to the flange so it kept causing the nut to
cross thread. Took me well over an hour to have success.
I take my hat off to the Porsche assembly people here, and I know where i
would stick it in the person who designed this setup. YMMV
======
A very good instruction document:
Fuel Sender
replacement.pdf
===
Removal of fuel Level sending unit in tank
I can't seem to be able to remove the sending unit. I tried to twist it in
different directions and pull up, but no luck.
I can get it as far as an inch out, but it wont go any further. I thought maybe
it was a weird shape inside so I turn it in several different positions but it
wont come out.
Is there a secret handshake for this?
MPDano
===
Got it! Basically there is a cap of some sort inside and the sender unit sits
inside of it. It was catching on the cap and in the time I was yanking on the
sender, the cap came loose and the sender came out. The cap must be put on
before they seal up the tank since the there is no way a normal human hand can
fit inside that top hole. Unless the Germans had hands the size of a 3 year old.
anyways, the sender looks fine as I can hear the float move up and down if I
turn it over. I am wondering what is the purpose of this cap and what are the
affects of not running it as I am forced to do.
MPDano
===
The cap goes on top of the lower bowl where the intank pump sits.
It stops crud getting into that area.
To clean the tank I use a high pressure washer with the pressure turned down a
little.
Depends how bad the Varnish like deposits are on the sides of the tank.
Roger
===
Be sure to replace all of the hoses before everything goes back together.....