Hi guys, come to pick your brains again. I'm fitting a new temp guage and not sure if I'm way off track or not. Haha. Can I combine the orange white and red and run them to the resistor as shown in pic. Then I've earthed the black at the guage end and the sensor end (as far as I can tell..) and the green I've hooked up to the red on the sender....
It illuminates but the guage doesn't get off 40.....
Like I said, I'm very non qualified but can usually figure stuff out....
It's not a good idea to use the ignition supply to the coil as a 12V for the gauge.
Depending on how your ignition is wired, the coil doesn't get a full 12 V.
You mention that you wired the gauge to the resistor "as shown in pic". What pic ?
I can see that you have wired a black wire to the negative terminal of the coil, which can't be right.
Where is your ballast resistor located ?
The reason that the gauge needs 3 different 12V supplies, is one is for the memory (colour selection etc.), one is to switch the gauge on & the 3rd is for illumination. Nothing wrong with putting the ignition & illum. wired (red & white) but I would be using a 12V supply (battery or somewhere in the dash) for that.
Yes, I only suggested the coil because the photo showed a connection slready, which I assumed would be positive. My FB and EK with original and reproduction wiring both get in excess of 12V at coil positive feed it later models differ I know.
FB ute fixer upper, EK van on rotisserie
getting my FB ute on the road
EK van on rotisserie
Dr Terry wrote: Mon Dec 16, 2024 7:35 am
It's not a good idea to use the ignition supply to the coil as a 12V for the gauge.
Depending on how your ignition is wired, the coil doesn't get a full 12 V.
From memory, the positive side of the coil has some funky voltage behaviour too as the coil charges then unloads. Not as screwy as the way the secondary voltage dances around, but probably enough to play merry hell with delicate electronic gauge internals.
Rob can probably describe this a lot better than I can, but the mental picture I have is that with the points open the coil sees battery voltage (assuming no ballast resistor), but with the points closed and current flowing the coil sees (battery voltage minus coil primary wiring voltage drop).
Cheers,
Harv
327 Chev EK wagon, original EK ute for Number 1 Daughter, an FB sedan meth monster project and a BB/MD grey motored FED.
Errol62 wrote: Mon Dec 16, 2024 11:41 am
Yes, I only suggested the coil because the photo showed a connection slready, which I assumed would be positive. My FB and EK with original and reproduction wiring both get in excess of 12V at coil positive feed it later models differ I know.
Original wiring for FB/EK will have a full 12V at the coil, but Red motors do not !
I notice that your coil is labelled "USE WITH EXTERNAL RESISTOR", meaning it needs a ballast resistor & therefore around 8-9 volts is required at the coil, not 12V. Also that terminal you speak of is labelled negative, so not a positive 12V.
Does your car burn out the points regularly, or does it have electronic ignition ?
The picture supplied by the OP is his coil. I didn’t look too carefully at it I admit. Certainly shouldn’t have anything temp gauge related connected there!
I have been running a 45kV output rated 12V coil with Bosch electronic distributor from VH. 13.9V measured at coil positive when running.
FB ute fixer upper, EK van on rotisserie
getting my FB ute on the road
EK van on rotisserie
Hi guys, yeah the old cheap guage my bro in law fitted was connected to the negative of the coil.. It was shitty and never read accurately (from the above I can see why!) Haha. I'm gonna follow Errol62 advice and go red (and white) from ignition behind ignition barrel..
I'll keep you guys posted.. I'll no doubt have more questions that'll cause a cringe or two.
Again, thanks guys, I appreciate the help.
Pablo.
I'm fitting a new temp guage and not sure if I'm way off track or not. Haha. Can I combine the orange white and red and run them to the resistor as shown in pic. Then I've earthed the black at the guage end and the sensor end (as far as I can tell..) and the green I've hooked up to the red on the sender....
