oil gauge issue it reads low pressure when pressure is good

[OldToys]

I have A 69 Super Bee (A-12) 440 with ralley gauges. the Oil pressure gauge only moves to about 0 or 10 psi and thats it. I installed a mechanical secondary guage and it reads about 30 psi. If the gauge was bad I wouldn't think it would move at all. I also tried 3 different sending units and all act the same. any ideas? (the engine is new and the oil pressure is fine)

 

[1967coronet]

You say {sending units} I would try a mechanical gauge on it before moving any farther. Post results

 

[OldToys]

maybe I wasn't clear i added a second mechanical gauge and it reads 30+ psi

 

[yella71]

maybe I wasn't clear i added a second mechanical gauge and it reads 30+ psi

You were not clear. you did not say a mechanical gauge was used. anyway looks like you have low oil pressure. dig in to the engine let us know what you find.

 

[OldToys]

You were not clear. you did not say a mechanical gauge was used. anyway looks like you have low oil pressure. dig in to the engine let us know what you find.

do you consider 30 PSI low? and thats at idle.

 

[R413]

You were clear to me. 30 at idle is fine, what about Pressure going down the freeway at 2500-3000 rpm? What weight oil in that engine.

what is the car you have? So we know something about your dash.

 

[OldToys]

You were clear to me. 30 at idle is fine, what about Pressure going down the freeway at 2500-3000 rpm? What weight oil in that engine.

what is the car you have? So we know something about your dash.

I corrected the original post to hopfully cover everything.

 

[1967coronet]

With the new info I would guess the problem is with the dash gauge.
In 70 i know mopar had a voltage limiter for the electric dash gauges. I'm not sure what year that limiter shows up.
Check grounds also , factory service manual with a good wire schematic and multi meter prob will be helpful.
30psi at idle is fine as long as it comes up with rpms.

 

[Wietse]

Other gauges read normal?
If only the oil pressure gauge it could be a bad grond on the pressure sensor on the engine, it normally grounds by the threads.
Using too much thread sealant could cause a bad ground.

You can remove the oil pressure gauge and test it by using 1.5Volt batteries.
0Volt = 0PSI and 5Volt is max, so 2 1.5Volt batteries in series gives 3Volts, with some electrical wire connect them to the gauge and it should should show more than half.....if it doesn't the gauge is probably bad.

The circuit board indeed has a voltage limiter that tries to maintain 5Volt to feed the gauges, but if this is faulty none of the gauges will work.

 

[66Satellite47]

A new rebuild with 30 psi at idle is on the low side, but what do you see at 2500-3000 rpm? The electric gauge needs work like others suggest.