P-12 Tommy Posted June 25, 2009 Report Posted June 25, 2009 What would cause a fuel gauge to go to 3/4 then to 1/4 then back? It does the same on Acc. or On. I put a new sending unit in and another dash gauge. All connections are tight and I even hooked a ground from the sending unit to the trunk floor. Tom Quote
TodFitch Posted June 25, 2009 Report Posted June 25, 2009 What would cause a fuel gauge to go to 3/4 then to 1/4 then back? It does the same on Acc. or On. I put a new sending unit in and another dash gauge. All connections are tight and I even hooked a ground from the sending unit to the trunk floor.Tom I'd have to double check the manual, but that sounds like one of the two wires that goes from the dash to the sending unit is either shorting out or opening up. Quote
BobT-47P15 Posted June 25, 2009 Report Posted June 25, 2009 My gas gauge does some goofy things too. It has new wires from sender, a new sender, cleaned the connections and grounds. Sometimes it goes to E, other times is more toward F which is what I know to be correct. So, I just live with it and know when it's working right. Better than the non working system I had for years. Quote
Plymouthy Adams Posted June 25, 2009 Report Posted June 25, 2009 the sender may very well be hitting something inside and preventing it's full arc or the unit itself could very well have issues where the wiper will be intermittant during the sweep. The guage in itself is a very slow to respond dampened unit that is designed not to move erratically even if the tank is subjected to spolshing the gas around inside..baffles or no baffles To test this unit you may want to use an ohm meter and check for erratic behavior and ensure that there is proper tension of the wiper to the resister body during its full travel..to try and view this with your guage will take a long time and a steady hand for the guage to respond to the new position of the float along its travel arc.. Quote
P-12 Tommy Posted June 25, 2009 Author Report Posted June 25, 2009 the sender may very well be hitting something inside and preventing it's full arc or the unit itself could very well have issues where the wiper will be intermittant during the sweep. The guage in itself is a very slow to respond dampened unit that is designed not to move erratically even if the tank is subjected to spolshing the gas around inside..baffles or no bafflesTo test this unit you may want to use an ohm meter and check for erratic behavior and ensure that there is proper tension of the wiper to the resister body during its full travel..to try and view this with your guage will take a long time and a steady hand for the guage to respond to the new position of the float along its travel arc.. Tim, I'll pull it out and check it again. To tell you the truth, I don't like the looks of the Andy B. unit. Kinda cheap. Tanks had me call a company they deal with that has sending units. They sold me one that's adjustable and comes with full instructions. It don't hurt to try I guess.Tom Quote
TodFitch Posted June 25, 2009 Report Posted June 25, 2009 Tim, I'll pull it out and check it again. To tell you the truth, I don't like the looks of the Andy B. unit. Kinda cheap. Tanks had me call a company they deal with that has sending units. They sold me one that's adjustable and comes with full instructions. It don't hurt to try I guess.Tom All the adjustable ones I have seen are single wire senders. I think your P-12 dash unit requires a two wire sender. Quote
Plymouthy Adams Posted June 25, 2009 Report Posted June 25, 2009 verification of the correct sender installed would be an ideal place to start...if a two wire as Tod says..it will never read correctly as the guage is pulled in both directions electrically to ground by the common ground of the wiper... Quote
P-12 Tommy Posted June 25, 2009 Author Report Posted June 25, 2009 All the adjustable ones I have seen are single wire senders. I think your P-12 dash unit requires a two wire sender. Yeah, I've got the two wire sender. I told them I need a two wire sender and that's what they're (Yogi's) supposingly sending me. If not I'll return it. BTW: I ran the car for about 10 minutes a little bit ago and now it's reading constant between 1/2 and 3/4 which is close with 9 gallons in the tank. Weird.Tom Quote
P-12 Tommy Posted June 25, 2009 Author Report Posted June 25, 2009 verification of the correct sender installed would be an ideal place to start...if a two wire as Tod says..it will never read correctly as the guage is pulled in both directions electrically to ground by the common ground of the wiper... Makes sense to meTom Quote
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