2.0L Fuel Gauge Question

[jjred1977]

I wanted to know if any knew the factory OHM range for a 1988 Ford Ranger 2.0L which is carbureted?

I recently had my fuel sending unit rebuilt since they are discontinued and impossible to find. The company that rebuilt it said the unit is now calibrated for 16 ohms empty to 165 ohms full. I'm trying to determine whether the gauge is bad or the unit is miscalibrated. My gas gauge has never worked before or after the new unit.

Is there a way to test the gauge?

Thanks,

James

 

[RonD]

Pre-1989 Fords, Empty 73 Ohms - Full 10 Ohms
Most '89-up Fords, Empty 16 Ohms - Full 158 Ohms

So the newer ones work opposite of the older ones

Yes, as far as the test.
Ford usually used a yellow/white wire for the gauge to tank wire, not sure on the '88.
There are usually 4 wires to the fuel tank, two will be Grounds for fuel pump and fuel gauge sender, these could be combined into 1 wire, never worked on an '88
One will have 12volts when fuel pump is activated, for a few seconds after key is turned on.
The other one will be for the gauge.

If that gauge wire is disconnected(infinite Ohms, high) at the tank connector, and the key turned on the gauge should go to below Empty, on the '88
If that wire is grounded(0 Ohms), with key on, the gauge should go to above Full, on the '88
This would be the same test on a newer model but gauge would do the opposite.

Because of the wider range of the newer sender and the opposite Empty/Full Ohms, you would be better off adding a 3rd party gauge or seeing if you can find a newer Ford gauge that matches your dash gauges.

You can build a circuit to reverse Ohms and adjust for the wider range but............time and cost

 

[Mark_88]

The 2.0 doesn't actually have an in-tank fuel pump due to the carb so you only have to worry about the sending unit wires. I have a Haynes with a wiring diagram for that but it isn't currently handy for me to check.

If you skip what Ron said about the pump and focus on just the wires going to and from the sending unit you should be able to determine if there is a problem by testing the resistance.

That can be done by simply pulling the cluster and sticking your tester probes on the gauge wires...

But, to be honest, it might be easier to simply pull the bed off, pop the connector, and sand the prongs that are exposed and put some dielectric grease into the female ends of the connector.

The sending unit wires just happen to be (for some strange reason) exposed to the elements because of the crack between the bed and the cab. It may serve you well to find a piece of rubber matting and slide it over the sending unit to try to protect it from the elements...I did this about five years ago and the matting I used is still there...still covering the sending unit...and even though my gauge has never actually worked properly on this truck...it still works to some degree...

My gauge goes from empty to full on about $35 worth of gas...but it is a 62 litre tank and that means that, hypothetically at $1.30 a litre, I should be spending over $70 to fill my tank...haven't done that yet though...