Oil Pressure Gauge/sender Issues

[timb1046 1]

I have a 1.9 MI16 in a 205, today, I was trying to get all of the gauges working, I identified the oil pressure gauge wire, by putting the ignition to stage 2, touchin the sender wire to eath and watching the pressure reading gauge the top, however, when the wire is attatched to the gauge I don't get a reading, I just get the gauge sitting at the top, I've checked some voltages, and with the engine running I'm getting a heathy 12+V to the sender wire BUT I'm also getting 12V+ from the sender itself! AFAIK the sender unit should just be a variable resisor to earth?

[Normski 1]

When I did my Mi16 conversion I had to run a seperate wire from the sender into the car as the Mi wiring loom didn't have a gauge wire (405 Mi16 don't have a pressure gauge but do have the sender).

So maybe the wire you have found is the low oil pressure warning switch?

[timb1046 1]

I've found two senders on the front of the engine, one (the larger one I belive is the pressure sender and the other is the low pressure warning sender IIRC however, one, when the engine is running has full resistance, so when plugged into either dash gauge wire gives no reaction to anything, the other, when plugged into the warning side of the loom causes the STOP light to illuminate and the oil pressure gauge light to illuminate too, and when in the other wire just gives a full high pressure reading. I'm very confused, alot of fiddling to be done tomorrow I feel!

[Normski 1]

The larger round sensor is indeed the pressure gauge sendor, it has just one spade terminal coming from it (as does the smaller pressure switch next to it). What wiring loom do you have in your car?

[timb1046 1]

the loom I'm running is very much a combination, it's got a partial dash side of the original 1.9, and a partial citereon BX loom engine side, with lots of my own added in bits etc. yesterday in the nicer weather I put a meter across from 12v+ to each gauge, both show the full battery voltage across them (engine off) showing that they are both earthy, this to me says that they're both completly kuput as they should have a high resistance when the engine is off, and then lower their resistance as the engine pressure rises.

[ade 4wd 11]

With ignition on disconnect oil pressure gauge and connect the wire to an earth. If the pressure gauge goes to maximum then the gauge and wiring is all good and its the sender unit that is faulty.

[timb1046 1]

that's what I've done, the gauge does go to max, and then when connected to the sender it again, goes to max, showing that the gauge has a full earth on it, I just wanted to check that my thinking was correct.

 

Many thanks