I think I might have an answer - I will try grounding the sender on the
body of the sender - and not directly where the sender wire is also
attached.

BT

On Thu, Jun 24, 2021 at 8:53 AM Bruce Todd <beeceetee@gmail.com> wrote:

>
> So - I am having some issues getting an aftermarket digital oil temp gauge
> to work.
>
> The sender connects to a threaded adaptor that replaces the oil
> relief plug - which I imagine many of you folks likely have in place on
> your beloved vans.  First question - if this is your set up, have you had
> to ground the sender since the bottom of the block is aluminum?  When I
> jumper a ground to the sender the gauge reads -18C which equates to 0
> Fahrenheit...(I opted for Celcius over Fahrenheit).  Without the jumper to
> the ground, the gauge reads full scale - 181C or 300 F.  Note - This is
> just with the ignition on without any temp being generated from the motor.
>
> When I run the motor with the sender jumped to ground and the sender wire
> attached to the gauge the gauge just stays on -18C and there is no
> fluctuation - so somewhere in this equation the resistance isn't dropping
> as the oil temp rises....which is how I believe things work with temp
> gauges.
>
> If I drive the van without the sender grounded - the gauge at full scale
> (181C)  begins to slowly decrease as the motor warms up - but continues to
> drop until it reaches -18C and then stays there - it doesn't set on a
> temperature.
>
> This gauge is from Intellitronix (M9108) and came with a sender.  I had
> originally installed a GW sender but then exchanged that earlier this week
> thinking it might be the issue as it may not be matched correctly with the
> gauge.
>
> When looking at GW (as a resource) they don't seem to mention grounding
> the sender - nor did the instructions I received for the gauge and sender -
> however I imagine they typically sell these units to vehicles that don't
> have an aluminum cases and the sender grounds directly to the motor.
>
> Any thoughts appreciated as I am running out of ideas here.
>
>
> Bruce
>