Board logo

irratic fuel guage
john_p_b - 30/5/05 at 01:40 PM

i'm so close to the end of the build now, just a last couple of things to do like securing the dash then i notice this!

i'm using VDO guages, everything wired up as it should be according to diagrams. every time i turn my ignition on the fuel guage shoots right around past the max point.

the float is deffinately not stuck up, that was the first thing i thought of.

the oil guage did the same wheni connected that but i cured that by adding an earth wire on the sender but everything on the guage and sender is earthed already.

anyone shed some light on it?

SeaBass - 30/5/05 at 02:07 PM

Sounds like a voltage regulation issue to me... Is their a regulator in the VDO setup. What voltage are the gauges meant to see?? 12v or less?

Cheers

pmc_3 - 30/5/05 at 02:08 PM

Is the sender supposed to be earthed? Does the guage not work by resistance on the negative, i'm pretty sure mine does.

carlgeldard - 30/5/05 at 02:38 PM

I have VDO Gauges and I did somthing silly with mine. I built the sender unit wrong and stuck the float arm on the wrong way around. Result of this was showing max fuel with none in the tank and no fuel when i filled it up.

Carl

john_p_b - 30/5/05 at 03:57 PM

the sender was pretty much all together when it came, all i had to do was shorten the float arm, hopefully there can't have been much i could do wrong with that?!

i tried removing the earth from the sender but still did exactly the same thing which makes me think it is a earth issue somewhere?

Peteff - 30/5/05 at 04:10 PM

Is the gauge earthed as well? Doesn't the gauge earth through the sender giving the variable resistance needed for a reading?

pmc_3 - 30/5/05 at 04:44 PM

quote:
Originally posted by Peteff
Is the gauge earthed as well? Doesn't the gauge earth through the sender giving the variable resistance needed for a reading?


That was my understanding too

mangogrooveworkshop - 30/5/05 at 04:50 PM

quote:
Originally posted by carlgeldard
I have VDO Gauges and I did somthing silly with mine. I built the sender unit wrong and stuck the float arm on the wrong way around. Result of this was showing max fuel with none in the tank and no fuel when i filled it up.

Carl


Thats easy to fix........F for finnished and E for enough !

rayward - 30/5/05 at 05:34 PM

Sounds like the cable from you sender to gauge could be shorted to -ve(or earth)somewhere along the way.

If you disconnect the wire at the sender end(the one that goes to your gauge) and see if the gauge drops, if it it doesn't then the problems not with your sender.

this page may help...

link

Ray

[Edited on 30/5/05 by rayward]

john_p_b - 30/5/05 at 06:27 PM

quote:
Originally posted by Peteff
Is the gauge earthed as well? Doesn't the gauge earth through the sender giving the variable resistance needed for a reading?


the guage is earthed as it shows on the wiring diagram for the guages, i have also tried disconecting that earth but then it all just stops working.