Oil Pressure Gauge

[Guest Ian Maycock]

the gauge has been fitted for a while. I have rewired all the gauges in order to move the fuses. it didnt happen before. i spoke with ETB who supplied the guages. they suggested it was the sender unit. this has been replaced and it is still happening. i fear i many have made an error when rewiring. i have even by-passed the loom and wired directly from the sender to the gauge, used a separate earth and live feed and it still happening??????????

 

Can anyone offer any advise???

[knights_templar]

Hi

 

ETB transmitter earth's through engine block, terminals on back are marked G for Oil gauge and WK for warning light.

 

Wire from G should connect to terminal T on the gauge. terminal B on the gauge should be ignition live through a fuse.

 

Any help?

 

Regards

[Guest Ian Maycock]

yes i tried that but the same happens!!

[sj-bradley]

Do you know what the sender is supposed to be "sending" when it's working? Sounds like somewhere between 0 and 12 Volts

 

You could then try and put a known voltage from a suitable battery pack to simulate a reading from the sender to see if the gauge reads it correctly.

 

You can also put an voltmeter instead of the gauge and see what readings you get with engine off or running.

 

I would first disconnect both ends and do a continuity check between the ends and also between wire and ground (chassis) in case you have a short there. (Before you put an ohm meter between wire and ground, put it on volts scale and check between wire and chassis then wire and Positive 12 Volts. You should NOT get any reading if that wire goes straight from sender to gauge as it should be insulated from both ground and 12 Volts)

 

I think (after re-reading your post) that if you have bypassed the loom and gone from sender to gauge, you should take a voltage reading between the sender-gauge wire and ground. It should be between 0 and battery positive. If it doesn't change with engine running or not running then you have a short somewhere. Sounds like you need to test the gauge on a separate supply off the car.

 

Simon.

[megadodo]

It is a resistance to ground not a voltage. You supply 12 volts to the gauge and the "sender"s resistance to ground dictates the the reading on the gauge. So if you set a DVM to read resistance it will vary with the oil pressure when connected to ground and I'm guessing somewhere between 50 ohms and 2000 ohms but that will depend on the manufacturer as I guess there is no standard.

[sj-bradley]

I have drawn a simple sketch to show what I meant.

 

If you attach the voltmeter as shown it should show a voltage between battery and 0v and should vary with engine off/idle/medium throttle.

 

(Pictures are worth more than words )

 

Forgot to add sender label on the resistor !

 

 

Simon.

[Longboarder]

Have you swapped the leads around on the sender? Try it.

 

Nigel

[Guest Ian Maycock]

The sender was buggered. i tested the resistance and there was non. so no alternative but to replace it with a new one. worksfine now.

 

Thanks for the advice.

[Longboarder]

Two duff senders is pretty unlucky.

 

Nigel