200Tdi Oil Pressure Gauge sender unit

[varleym]

Just got round to fitting a new oil pressure gauge (not switch) sender unit after the old one broke on Mudmaster last year. Got a sender unit from T'bay, fitted it OK, but when the ignition is turned on the gauge (Sunpro) flicks right over to the right and when the engine starts comes back to the middle (settles at about 60 psi when idling). In addition, when you rev the engine the gauge actually moves down slightly.

Now I assume that with all things in life - there are some combinations of gauge/sender unit which work with the voltage going one way and some which work the other way. I've obviously got a mismatch between the sender unit and the gauge.

Anyone know how to tell which is which? If I've got to change anything I'd rather get a new sender unit 'cos that'll probably be cheaper but if the Sunpro gauge runs the other way round to most units I guess I'll have to change that.

Any advice?

Cheers

Mark

[Bo]

Hi Mark, sender should just alter resistance as pressure rises. Try putting a multi across earth and the terminal in off, idle and at pressure.
Bad earth will increase resistance and give low reading so might be worth while double checking connections.
Manual are here:
http://www.sunpro.com/user_manuals.php

Failing that search "Sunpro CP7577 Oil Pressure Sender" on fleebay or Amazon.