BF GTX fuel gauge problems

[1579]

Hey Guys,

My BF gtx has a weird condition. The fuel gauge refuses to work unless i fill the car completely. Then it will read normally between full and about 7/8 tank, anything below that level the gauge just dies... falls to E. Analogue cluster.

I tried swaping both sending units with some from a parts car I had. I see there is a procedure to check the resistance on the float sensors, but I figured I'd try a quick post on here first seeing as I wont have time to pull the car apart untill next weekend.

Anyone had a similar issue or any thoughts as to what I should check first? The car has always had this problem, since I bought it about 5 years ago. I dont really know how the dual sending units work together to give a signal to the gauge. Can anybody enlignten me?

Thanks in advance. Any input appreciated.
Brandon

EDIT- oh, just thought I'd mention. The low fuel light still works great.... Thank goodness.

Also, I tried looking up the testing procedure in the manual above, my connector is 6 pins for the main pump side (lh) and 4 pins for the transfer pump side (rh). The diagram specifies 4wd, mine dosnt look like that though. Anyone know if the resisance values should still work?

[trailrider098]

Yea, this is a common problem. Mines benny doing it for years too. Anyways someone on the yahoo GTX forum just did a great write up on how to fix the problem by re-winding the coil which wears out.

[1579]

Yea, this is a common problem. Mines benny doing it for years too. Anyways someone on the yahoo GTX forum just did a great write up on how to fix the problem by re-winding the coil which wears out.

So even though I swapped the entire sending units over, the coils which the floats slide on are probably the culprit eh? I really need to get out the multimeter and quit being lazy.

Thanks for the guidance!
Brandon

[BFMRGTX]

On top of that, the gauge is never accurate. I have to reset the tripmeter each fill-up and try to keep it from not going over 240 miles.

[1579]

Anyone have that writeup on rewinding the coils? I can't seem to see it.

[samsquanch1981]

Anyone have that writeup on rewinding the coils? I can't seem to see it.

By cornerspring

"So I wrote this little write up for everyone...pretty sure I'm not the only one
how's had this problem.

origial thread:
[URL="http://www.wihandyman.com/forum/showthread.php?57674-how-too-fix-your-fuel-leve\ r-senders-and-for-only-5!!!"]

So like many poor old mazdas (mine happens to be a GTX, but this should be
applicable to lots of older mazdas) My gas gauge meter was on the fritz. When I
first would fill up the gauge would read full, then only a few miles down the
road the gauge would drop to zero. What a nuisance!. So I went on a quest to
track down the root cause. Low and behold it was the level sender(s). The level
senders are a simple potentiometer, more specifically, it's just a little arm
that travels up and down a wire that is twisted around a little plastic spool.
Over time the arm actually wears thru the wire causing a break...like this:

http://img4.imageshack.us/img4/8719/imag0437n.jpg

So it seemed like a simple task to just rewind the spool with new wire...and
guess what....it is! The hardest part is removing the spool. So on with the
how-to:

What you'll need:
- old fuel lever senders
- soldering iron, solder, and the know- how to use it
- new wire. Needs to be 31AWG copper. I got mine off ebay, it's sold as "magnet
wire", and can be had on a tiny little spool.
- misc hand tools for pump removal and dis assembly

So step one, remove the level senders..pretty self explanatory..

Step two: remove the cover from the level sender. Simple stick a flat blade
screw driver in the opening along the top side near the tank cover. push it away
from the cover while pulling it away from the level sender mount.

http://imageshack.us/photo/my-images/827/imag0449p.jpg

Step three: bend the 4 tabs that hold the spool in place so the spool can be
removed. Unsolder the wire attached to the spool

http://imageshack.us/photo/my-images/27/imag0450h.jpg

Step 4: remove the old wire from the spool.. You may need a tiny little screw
driver to bend the mounting tap that the wire in the last step was soldered to,
as it it deformed to hold the old wire in place.

Step 5: Wind the new wire around the spool starting at the end with the solder
post and working away from it. You need 42 winds. Tuck the first two
winds under the tab, and band it back into place. Leave a little extra on the
end in case you need to solder the tip to the solder tab. My spool had little
indents in it for the wire to sit, so it made getting the spacing perfect an
easy task. but if yours doesn't, get it as close as possible, but being a little
uneven is fine. To secure the wire at the end wrap the end of it around one of
the little feet on the spool, and tuck the wire back under itself.

****NOTE****
if you are using "magnet wire" be sure to sand the coating off the wire where it
will contact the solder tab, and once it's wound, sand the tip that contacts the
wiper arm to remove the coating. You should be able to get continuity between
the arm and the solder tab at any location of the float otherwise you will have
dead spots in your gauge.

http://imageshack.us/photo/my-images/24/imag0438f.jpg

http://imageshack.us/photo/my-images/812/imag0439pw.jpg

Step 6: reassemble in reverse order, and reinstall in the car

Step 7: enjoy not running out of gas anymore!"

[1579]

cornerspring and samsquanch 1981, thanks soo much. Definitely going to try this, the dead fuel gauge has been driving me nuts for years.

[1579]

Well boys i'm in the midst of this right now. I counted 75 winds. What in the ****.

This was on the LH (primary??) fuel sender. The one which also has the high pressure fuel pump on it (walbro in my case).

The RH (secondary or transfer) sender appears to have 42 winds on the spool and thicker wire. More updates to come, I'm headed back out to the garage. I am going to wind it as it was (75 winds) and see what happens.

[1579]

the winds are different depending on side I think. LH sending unit wind count seems to be roughly 75. Mine works for the first time since I got this car. Whoo! I just need to confirm it's accuracy.

[estebond008]

Did you have any luck with this? My GTX is doing the samething and anyday now I am going to take it apart to attempt fixing it myself.