ahar

iTrader: (3)

Following on from a question that I asked about oil pressure a couple of weeks ago (https://www.scoobynet.com/general-te...-standard.html) it looks like the previous owner has attached the PSi3 monitor that I have to the OEM oil pressure switch to try and monitor oil pressure.

The result is that the PSi3 displays the oil pressure but it doesn't move much. The pressure stays between 6.4 bar and 5.9 bar whatever I'm doing. Now its been doing this since I bought the car 18 months ago, and the standard oil pressure switch on the dash board does work (found that out when I changed the oil earlier in the year and disconnected the crank sensor to turn it over until the oil light went out).

Has anyone tried linking a PSi3 to the OEM oil pressure switch and what results have you had? I'll probably replace it at some point with a Defi sensor but for now do you reckon the readout on the PSi3 is useless or is it just not very accurate?

Splitpin

Are you absolutely sure that the PSi3 oil pressure connection is actually connected to anything, or are you just assuming that to be the case because you get a reading? If it is floating open circuit you will probably see a number of some sort that varies a little bit, but the reading will bear no relation to the actual oil pressure.

Haven't tried it but can tell you now there'd be no point. As you say, the OE oil pressure switch is a narrowband switch not a sensor/transducer. It reads on or off, dependent on whether the pressure it is exposed to is above or below its switchover threshold. It cannot accurately report changes in pressure beyond that threshold no matter what it is connected to.

If your original suspicion is correct, and the PSi3 oil pressure line has been teed into the wire from the OE pressure switch, the reading you get on the screen will be next to meaningless.

If you connect it to whatever type of transducer it was originally designed to work with (the Defi one IIRC) it should be pretty accurate.

ahar

iTrader: (3)

Sounds like I need to take the PSi3 out and check what is plugged in. I assume that I would see a separate cable running into it

Splitpin

Well worth doing. You would see a second cable run - there should be sockets on the back of the monitor for the oil pressure and temperature sensors.

ahar

iTrader: (3)

Aha, the mystery is solved as there are no other cables plugged into the back of the the PSI3 so the oil pressure that it displays bears no relation to the actual oil pressure.

So I may decide to get an oil pressure sensor and fit it. However, there don't seem to be any connectors on the back to plug it in that look anything like the pictures on Scoobynet of Defi connectors. With PSi3 now out of business so I can't ask them, does anyone have an idea of how I would connect a sensor to the back of it (pic below). The small connector on the right is where the ECU cable plugs in - any idea where the oil pressure cable would go?


http://i48.photobucket.com/albums/f229/PSi3/vfd3.jpg