Temp Gauge

[jaimo]

Done a few jobs today but temp gauge still not working ran new wire from sender to clocks and if you earth it out the gauge goes up but when its on sender nothing ran engine and the pipes didnt get hot so took out seized thermostat order 1 tomorow and ran again for at least 10 mins temp gauge didnt move tried a different used sender and still nothing do i have to match sender to clocks.

i have orignal sierra clocks from 1983 2.0 and the engine in hood is 1.8 both pinto so how do i know wot sender to get or cud there be orther probs

Edited May 10, 2015 by jaimo

[jaimo]

I see you can get white top, black top onescetc what's this mean

[sj-bradley]

Yes, the sender needs to match the clocks you use. This applies to fuel gauges and the temperature sensor too.

 

It depends on what the sender is doing. If it's just changing resistance. you can check this out with the Ohms setting on your meter.

I could then tell you if your sender is actually working (It probably is, but your meter is expecting something different)

 

Simon.

[sj-bradley]

Temperature sensors can be one of these

 

1) thermocouple (unlikely)

2) Thermistor (probable)

3) an active device like LM335 (if there are three wire going to it, it's probably active)

 

Each produces an entirely different type of output.

 

Simon.

[jaimo]

Its one of these Simon

http://pages.ebay.com/link/?nav=item.view&id=141561506112&alt=web

[sj-bradley]

I looked at that and it looks like a two wire job (The case is earthed - that's the second wire) so it's probably a thermistor.

 

However, it doesn't give me the specs on the temperature range or what the resistance ranges it should be. In order for me to be able to tell you if it matches your gauge, I would need to measure the resistance when cold, hot etc as well as the max current that your gauge needs when shorted to ground.

 

I did a quick search and thermistors can come in two types, positive and negative depending on whether their resistance goes up or down with increasing temperature.

 

I could design a circuit that would make that sensor work with your gauge, but I would need to see it. And don't fear the price. It would be no more than a 4 pack of beer

 

Simon.

[jaimo]

When i get new one simon i will give u a shout as shud move gauge wen hot even if reads wrong and at mo it not moving but earth wire from it to gauge and it does

[sj-bradley]

This sounds like the old style gauges which rely on a heating element inside it.

 

The sender may not be sinking enough current to work the gauge. I can make something to work between these, but I do need to see them myself.

 

Simon.

[Guest mower man]

As far as I remember [?] temp sender on fords of that era are all single wire there are colour diferences which are matchable by age to clocks but they all work in the same manner but give different scale ranges , make sure no sealant on the threads as it will stop the thing working mick

[sj-bradley]

The single wire is a misnomer really.

 

As you say Mick, the threads need to be in electrical contact to complete the circuit to the chassis. The one wire in is only 1/2 of the circuit and people do not realise that the body is the other 1/2 which needs to have an electrical connection to the chassis.

 

If this sender is mounted in a T-piece with rubber hoses, it will also not work correctly. It NEEDS a solid metal path to the chassis earth connection to work.

 

Point taken about them being colour coded - I did not know that, but I can see why.

 

Simon.

[nigelt]

Hi Jaimo,

 

When you connect the sender wire to earth/chassis, (if you haven't done this already), try grounding it against the body of the temp sender. This will instantly prove whether or not the sender is grounded, or insulated from the chassis in some way. If the gauge moves when doing this, then it is probably just a mismatch. If not then you need to look at why the sender is insulated.

 

Nige

[Guest Ian & Carole]

Even a miss-match will give a reading of some kind though.

[sj-bradley]

Not necessarily. A gross mismatch may not move the gauge at all.

 

Simon.

[jaimo]

Hi all temp gauge fixed just new sender required now just wants an electric fan instead of the vicious