Can anyone help, I have as most know an XB falcon tank in the FB. The standard holden gauge won't work with the XB sender unit so I got a XB gauge. Fitted that and it still won't work properly. It just goes to full and starts to send up smoke signals.
Does it need some sort of resister or something in the line.
Any help would be appreciated
may sound silly but sounds like it could have a short to ground
on the sender wire
or make sure the sender is earthed and the gauge body as well
as if not both earthed some will shoot up to full and wont to keep going
i had this problem on my cadillac
Sorry Malcolm,
got to go to bed - been a bit busy with others site stuff for a few days............
will try and have a think on it overnight - should have something up tomorrow night - ooppss...... tonight - gotta go to bed, very, very tired...........
probably just throw up a whole lot of stuff which won't make any sense.
Hi Malcolm,
been off the site for a few days getting some air.................
Did you get your fuel gauge issue resolved?
I gave it a bit of thought and don't know if I posted anything back?
The gauge in your dash works by resistance - it is actually a resistance meter.
It receives it's load (or signal) from a like resistor in the tank unit.
A voltage is forwarded across the gauge needle resistor and is sent to "earth" through the resistor in the tank (sounds a bit scary, doesn't it?).
Depending on how much "resistance" the float is throwing back towards the needle causes it to deflect to either the full or empty side of the gauge.
For all intents and purposes, the needle works exactly as an analogue multi-meter does when set to "resistance".
For everything to work properly, all wires and connections must be sound and isolated from the body.
the danger to the instrument is if you connect the positive lead on the back of your instrument gauge to the sender connector from the tank - it will blow the gauge. or if power is sent down the tank wire (brown) it will "blow" the tank unit....................
When you introduce an alien component - it must be either adjusted or the values calibrated to provide for a suitable signal to make the dash unit respond accordingly................
I ended up getting a NOS XB fuel dash gauge, taking the guts out and fitting it to the FB gauge housing. I then got a external resister to handle the current side of things.
After fitting it all up it worked fine until I put fuel in it and found that the gauge is reading ass about. So when its full its showing empty on the gauge.
So I just dont know if it is possible to reverse the wires on the back of the &*#@ gauge. There was nothing indicating what wire went where on the back of the gauge so I just took a punt when connecting the wires.
Hi Malcolm - I wouldn't change the wires over - if it's like our AC gauge - you'll blow the pot in the tank unit.
Some would say, change the E to an F on your gauge and vise versa - not the way I'd do it, but it would certainly be "unique". The letters are such that you delete a bar on one and add one to the other................?
Guess you could be then guilty of "running on empty.............."
My immediate thought is to reverse the polarity of the tank unit - just thinking - can't you hear the noise from up there?
umm............ we'd need to insulate the tank unit for that - no don't.
Dash gauge is going to be easier - we need to break it open and change where the lead connects to the resistor wiper of the needle - so that it starts at the other end of the scale as resistance increases/decreases what ever the &*#@ Motor Company aka FoMoCo (gosh, I thought this site would go into meltdown if I typed that into a post - obviously there isn't a "filter" on the site for that word).
Will do some more thinking on it for you Malcolm - hopefully will come up with something overnight.........
good public service advice - "don't do anything until I get back".....
frats,
Rosco
ps DON'T reverse the positive and negative on the back of the gauge - it will most certainly "cook" the tank unit pot (potentiometer = what changes the resistance as the float rises and falls)..
hi malcom, going through a similar senario with a VN commodore tank in my FC. i was going to go with a speco fuel gauge but found that my VN sender isnt compatible, but they can rewind ( or modify) the sender unit to suit the gauge. cost = new gauge and sender + modify VN sender $$$ ( or punch another hole in my tank for speco sender)
i rang howard instruments in VIC ( do a white pages search) and found they can install a 0-30 ohm unit in my VN sender to suit the FC guage. very simple & for less than it would cost to buy the speco gauge. at the most it is going to cost $115 could be as low as $80
and gives me peace of mind knowing its done right.
they are really helpful and the lady on the phone knew what i was talking about straight away. my sender is going to them next week.
just another thought for you, not too sure about reversing polarities that close to a fuel source?
Hi Malcolm,
I didn't come up with naything new overnight - gave it a good think and just don't know what I'm up against with the oval setup.
I am still of theoinion it would be best to leave the tank end as is - I feel it fairly critical to let the design engineers have their way when it comes to the potential of petrol.........
Does your gauge show correct parameters - ie does it go full scale with the tank both full and empty of fuel........ if so, then all that is needed is to change direction of the needle driver.
If there is some discrepancy in the figures and indiactions ie not going fully either way or showing max when it is not at the true limit - it needs some form of re-calibrating to bring it all into line.
I think Smithy has the commercial answer - I prefer to "project" my own needs............. it has been part and parcel of how I have learned my vehicle and what makes it tick (or not!).
A good auto spark should be right up on this - you would not be the first to present the issue -
Let me know what your auto elec came up with - I am very interested to learn.
