FUEL Gauge
my Duster the gauge needle will get to about 3/4 drop back to around 1/2 and stay there as I drive it drops to MT but
i can still go 100 mile b4 I run out. Is it gauge ground or what LOST
The gauge going to 3/4 then to 1/2 ( IMHO) rules out leaky float. If float was filling it would not empty itself then start refilling
The IVR (if mechanical and the RT Engineering unit) has a warm up period where 12 volts is fed to the guages for a few seconds. This gets the needle moving pretty fast, then it starts it's on off dance to regulate the voltage to the 5 to 6 volts square wave needed by the gauges.
What you might be seeing is the initial warm up period of the IVR.
As for the empty and still have 100 miles on the tank ( not a bad thing!)
My guess is there is exsess resistance in the path from body ground to the sender, to the wire, to the gauge. This extra resistance will fool the gauge into thinking it is lower than it really is.
As mentioned before you need to get some resisters ( 1 watt) in the 10, 23 and 72 ohm range and then go between good body ground and the wire at the sender.
And report back what the gauge does.
Other issues might be:
- a failing IVR, sticking closed,
- a failing gauge (post a photo of the gauge with the key in the off position)
- If you removed the sender you might have messed up the adjustment (at some point between 67 and 76 the design of the sender changed and messing up the adjustment is harder)
- And as mentioned be sure you have a good ground from the sender to the car body. A temporary jumper cable will work for testing.
