Oil pressure? Follow up

[Jim Haseltine]

I wrote:-
>The sender that failed is #035 919 561 A 0-5/1.8Bar and the old one which
>I've refitted is #035 919 561 0-5/0.3Bar. Now I'm not too certain whats
>happening here, it could well be that my engine is suffering low (<1.8 bar)
>pressure but not low enough for the 0.3 bar to switch. I figure that I need
>to hook up a pressure gauge directly to the engine and also to try another
>1.8 bar sender. Luckily, there's a 1.8 sender on my parts cgt, so I can try
>it this weekend.


What a dummy. These senders have TWO terminals but only one (marked 'G') is
used on the ur-q. On my cgt BOTH terminals are used, one for the 1.8bar
warning switch and the other to feed the oil pressure gauge.
The instructions for checking the sender on an ur-q say that the 'G'
terminal should have the following resistance figures
With the engine off, the reading should be 5 to 10 ohms.

With the engine idling, the reading should be 70 to 120 ohms.

With the engine at 3000rpm, the reading should be 170 to 200 ohms.
(when I increased the revs, the resistance gradually climbed)
The other terminal,
With the engine idling, the resistance should be zero to 0.5 ohm.

With the engine off, the resistance should be infinite.
(so its a switch)