Part no148677 Ferrari

We are a bit backward in the US but we do have kitchen stoves and pots of water. Just need wife to leave the house for a couple of hours... Battery charger will provide 12v

 

One way to check over 100C temps is to heat oil as boiling point is much higher than water. Cooking oil will do if checking needs to be done in kitchen with wife approved ingredients.

 

Wife just left. I have a 2hr window. Here we go.

 

Results with a big "but."

27.2 = 2260 (room temperature)
40 = 1800
80 = 292
100 = 163

Circuit is normally closed and opened somewhere just after boiling.

The big but is the water started to boil before 100 somewhere past 95. So the sender does work but I am not confident with the readings above as I do not believe the temperature is exact enough for comparison.

I think I could live with the output of the chinese gauge as the numbers seem relative and the thermal circuit closed somewhere around boiling.

I used a laser tester and I am not certain of its accuracy.

 

I got that backwards. The circuit is normally open and closed somewhere just after boiling.

 

It looks to me that the thread size of the original sender is 3/8 NPT and not M16 (3/8 NPT is/was one of the standard threads for senders).

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Strange. You would think that 127C would be much higher than boiling.... if the Ferrari sensor is triggered at 127C. Was the sensor sitting in the bottom of the pan, touching the pan, or was suspended above the bottom of the pan?

I'll take some measurements when the Fiat sensor comes*. I've also purchased some resistors which I can attach to the gauge wiring to see what values are produced on the gauge.

*(EDIT: I just found some metric thread gauges, so I should be able to see if the Fiat sender is metric or something else)

I have a laser tester, but I might try a food thermometer.

 

I checked the coolant temperature sensor for the F355 engine ECU and the thread looked metric (1.5 pitch x 12mm). The thread angles looked the same and when I held the sensor and thread gauge up to the light, there was almost no light leakage. The gauge sensor, of course, might be completely different.

 

It's M16x1.5. I measured it.

 

I tried a food thermometer. One for measuring meat. Worse results. Jumped around a lot.

I am not sure where you are getting 127c. The chinese specs say 117c. I suspended the sensor between two wires (ground and sensor lead and just dipped the tip into the water like the housing.

 

Not sure either. I got it right earlier.

117C is still quite far from 95C (as you said earlier)

 

Agreed, but I do think my 95c is 95. I think it is closer to 100c and the circuit closed well before 117c on my laser reader. My point is that everything seemed relatively correct and the circuit closed just after boil. So the chinese specs I could live with.

 

I still don't understand how you could get 117C from an open pan of boiling water. I thought the water had to be pressurised to reach that.

I'll see what numbers I get with my gun from an open pan/pot.

 

Ian- It does. Will stay at 212° F or 100° C at sea level until it boils off.

 

Wouldn't the metal sensor continue to gain heat, thereby increasing even though the water limited at 100? Maybe it tripped at 100?

 

The metal is relying on heat transfer from the water. If the water doesn't go above 100C, then I can't see how the metal can. I think one of the laws of thermodynamics covers this. Heat will transfer from the hot to cold. The metal can't get hotter than the water because the heat will flow from the metal to the water.

Not related, but I was testing a new F430 radiator fan switch today with two internal (different) temperature switches. One is 92C, one is 97C. At least I know the water can get hot enough to reach 97C to trigger the switch. Took a while to reach the second temperature, though.

 

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As mentioned above, I bought some resistors pretty close to the 40C, 80C and 100C resistance values shown on the chart.

I don't know why I bought a 1500 ohm resistor, because I don't have 40C on my gauge. The needle didn't even move from the stop.
The 330 ohm resistor (close enough to 350 +/-35 ohms) registered about 60C (the next increment above 50C)
The 200 ohm resistor (close enough to 190 +/-19 ohms) registered only 80C (the third increment above 50C)... see photo

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Either my gauge is broken or the Chinese values don't represent the Fiat sender.... or the Fiat sender is different from the Ferrari sender.

I think I'll invest in a "decade box" so that I can check the values across the whole range of the gauge.

 

If you're wondering why my oil pressure gauge is pegged to the right, it's because when I was doing the tests, I disconnected a harness which carries a lot of engine data. High resistance/open circuit causes the oil pressure to go high.

 

My decade box arrived today. Here are my resistance vs water temperature values (gauge readings):

50 deg = 470 ohms
60 deg = 350 ohms
70 deg = 270 ohms
80 deg = 200 ohms
90 deg = 150 ohms
100 deg = 125 ohms
110 deg = 90 ohms
120 deg = 70 ohms
130 deg = 55 ohms

I'd say give or take 10~20 ohms (at the lower temperature end).

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So basically nothing like the Chinese values.

The Fiat sender hasn't arrived yet, so I don't know if it will match up with my values or the Chinese values.

 

Interesting. Did you buy a new or used Fiat sender?

 

The seller claims new. It's been about 3 weeks since it was posted, but I have no tracking information to tell me where it is at the moment.

 

Update... 6 weeks later... Fiat sender lost in the mail. Seller is looking into it.

Oh well.

 

Best laid plans of mice and men.

 

Hi guys, just wondering if the fabled trst of the fiat part ever happened? I have the gauge dancing about on my 355; usually just spikes up to max temperature as soon as it registers anything, even when the engine is hardly warm at all (I could literally put my fingers in the coolant tank ). Be interested to know if there is an alternative to the rather pricey options on Eurospares.

 

No luck.

I assumed they were NLA, but Scuderia Car Parts seems to have one for UKP83.23 plus VAT?