thorneycroft T90

[fiddle]

Im having trouble with my oil pressure guage, or the sender.

When I swich on the ignition, the guage wizzes over to the other side and stays there until I switch off. This is before I crank the engine so I know its not related to the oil pump and real pressure. It is affecting my ability to measure the pressure.


Also, where is my sender? At the back of the engine, close to the bell housing on the starboard side, by the injectors, is a device with a pos and a neg connection. I have another device similarly connected though a different shape, in a similar place but on the port side. Now I know where my water temp sender is, and one of these two must be my oil press sender, so whats the other doing

The engine is based on the BMC 1500 of about 1983

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[cliff]

If I remember correctly one is oil pressure and the other is oil temperature. Easy way to find out which is which is turn on your ignition and disconnect the leads from one of the units - is your gauge still reading full pressure? if yes then reconnect the leads and disconnect the leads from the other unit. - is your gauge still reading full pressure? if no then reconnect and see what happens - now reading full pressure? if yes you have found the pressure sender and logic says it is duff. If you remove leads from both units and the guage still reads full pressure I would suspect a short somewhere in the wireing between the sender and the gauge. I personally prefer the old fashioned hydraulic gauge - no sender or electrics to worry about.

Hope this helps

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[brianhumber]

A good reliable DIY engine. Your problem sounds like a short or more unlikely sender/gauge fault. If the wiring loom is 1983 try to check by removing leads on unknown sender units one by one, till you identify pressure sender. Then check out wires insulation for touching/wearing through. not a big job, new senders, gauges are still available and wiring is auto grade with auto spade connections.

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[PeteMcK]

One unit is rev counter, the other is the pressure sender: can't remember which side's which, but the bigger unit is the rev sender. I think full scale means you've an open circuit - remake the connections.

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