3200 Oil Pressure Sender

allandwf

Member
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10,958
Listed is as much detail as I have on the 3200 Oil Pressure Sender.
Thread M14 x 1.5
Range 0 - 8.0 Bar
Internals Jaegar Marked 339031
Measured Resistance range, 3 ohm to 277 ohm, ( seems odd to me.)
Markings on nut flats, 8B , 12V, 30F6, 401, 981, 01. ( First two are range and supply voltage.)

I will post a picture of the internals so you will see where the main problem lies with the interference connection between internals and socket.
 

allandwf

Member
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10,958
DSC_2068[1].jpgDSC_2069[1].jpg
In the first picture you can see how the electrical connection is made purely by the pin in the socket pressing against the flat spring. Not a good design for reliability.
The second shows the resistor and wiper, which will wear out eventually, but the majority of cases of bad/fluctuating readings will be the connection problem. If someone finds a way of opening and sealing them again neatly and the connections were soldered, then the majority of problems would be solved.
 

StuartW

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9,306
... and they seem to have a life of not much over a year in some cases, a very fragile bit of kit
 

Moz1000

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820
And it's all grossly subject to changes in temperature. Mine would be fine when the engine was cold/warm, but once full operating temperature was reached, it would become erratic. And now I can see why with all those moving parts. However, I think the main culprit is the 'touch' connection between the connector pin and the internal contact. If these parts can be soldered (the parts would need to be copper, brass or plated with nickel or tin) then a wire could be soldered and the assembly remade somehow (Epoxy?).
Dave
 

allandwf

Member
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10,958
And it's all grossly subject to changes in temperature. Mine would be fine when the engine was cold/warm, but once full operating temperature was reached, it would become erratic. And now I can see why with all those moving parts. However, I think the main culprit is the 'touch' connection between the connector pin and the internal contact. If these parts can be soldered (the parts would need to be copper, brass or plated with nickel or tin) then a wire could be soldered and the assembly remade somehow (Epoxy?).
Dave

Correct, soldering will sort about 90% of the issues, it's getting it opened and sealed again neatly that's the issue.
 

Zep

Moderator
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9,110
Interesting. Looks like a lot of Fiat and Lancia cars use a similar item. Lancia Delta integrate is the same range (I think) with an M14 fitting but is still an expensive item. An Alfa 155 (or Landcover Defender!) have a 0-8 bar range but is an M10 fitting - I have found a bush to adapt it off the shelf for about £7. I assume the 277 ohm is at 8 bar and 3 ohm is at zero?
 

Arvid

Member
Messages
158
I assume the 277 ohm is at 8 bar and 3 ohm is at zero?

It's the other way around. Close to 0 ohm at full indication on instrument and 277 ohm at 0 bar. If you earth the sensor lead,the instrument would read maximum bar.

A big thanks to Allan for helping out with good information.
 

Zep

Moderator
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9,110
Oh yes, I got it the wrong way round! The Alfa 155 sender would work then, just needs a £7 bush to fit.
 

Arvid

Member
Messages
158
Allan,

Can you see if the arm uses the whole resistor plate for its movement or just 2/3 ? If so,could you measure the resistance from the point where the arm stops,where it most likely stops at max pressure ?

These are 8 bar senders but possibly the pressure isn't that high. It may be possible to use a sender with another internal resistance since the 0-277/280 ohm is almost impossible to find. 240 ohm is a more available part from several vendors.

Arvid
 

Zep

Moderator
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9,110
My understanding of the available ranges is that the Alfa / Lancia units are 240-33 ohm. The gauge only goes to 5 bar so the crucial question is whether 240 ohms reads as 0 on the gauge.
 

allandwf

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10,958
If I can find an adapter here I will check. If not it will need to wait until I am back at work. That was my worry, I don't know what range the ECU looks at in voltage, and obviously more than 5B as it is usually hard upscale. I will try and find out what 8 Bar equates to resistance wise. Watch this space.