Oil pressure gauge/sender issues

[texas30cal]

When I got this deuce going a few weeks ago the oil press gauge didn't work. When I went to work on it the second time I took a new gauge and sender with me, installed just the sender and the gauge worked fine for about 3-4 days. Now the gauge pegs out when I turn on the main switch and works somewhat normally as the engine warms up. I know it works off resistance and is basically a variable ground so my question is could Teflon tape on the threads be insulating it causing a problem?

 

[texas30cal]

I forgot to mention that I tried the new gauge with same results and I had the whole dash out over the weekend for cleaning/painting. While it was out I looked at every connector, found none dirty but blew them out and put nyogel in every one. I did find one with a bit of insulation missing but not much, cleaned it and taped it up. Where can I find a replacement for the grommet/protector where the main harness comes through the firewall?

 

[rosco]

Check too for bad insulation on the sending unit wire to the gauge. Partial grounding will do the same.

 

[MG2936]

I was having the same problem. I finally bypassed the harness and ran a wire directly from the sending unit to the gage. Bingo...problem solved. As Rosco suggested, the wire in the harness was grounding out someplace.

 

[dmetalmiki]

The best solution is to replace that gauge (and the water temperature gauge) with capillory type devices. wysiwug! And actually both (all on every truck) are the alternative notification circuit type. All the time 'on' (then 'off') OR all the time 'off' then 'on'.
I use them all the time 'off' and if no oil pressure then a buzzer sounds and a red light flashes.
If temperature climbs too high A flashing light comes on and a buzzer sounds.
Google the type, as they came from the U.S.A. originally,ohio I believe, Ive had them fitted for over 10 years,

 

[66m35a26x6]

I would just run a mechanical oil guage and be done with it..
thats what ive done no issue's.
will never lie to you

 

[texas30cal]

I just got finished, the wire was grounding somewhere, disconnected both ends and checked to ground, Es no Bueno. Used the original ends and ran a new wire, works like a champ. Also fixed my poor charging issue, cleaned all connections and still no good. It helps A LOT if the belts are tight!! UGHHH On to the parking brake next