No oil pressure at start up

[chevybones87]

Ok I have a 1980 k10 4.1L 250.. When I start it up cold to warm it up it has no oil pressure for about 5 mins the all of a sudden jumps to 50.. Its worrying me so any advice would be great.. Thanks guys.... ALLEN

[zieg85]

More than likely it is a sluggish gauge

[bd]

         ... or sending unit.

Unplug the sending unit wire from the sender and connect an ohmmeter between a good clean ground (such as the metal body of the sender) and the sender terminal.  Set the parking brake and have an assistant start the "cold engine" while you monitor the ohmmeter.  Stay clear of the fan and belts.  The sender should measure approximately zero at zero oil pressure, before starting the engine; 30 ohms at the center line of the gauge and 60 ohms at the maximum line of the gauge.  If the sender responds immediately when the 'cold engine' starts and measures 30 plus ohms, the issue is in the gauge or its wiring.  If the sender is sluggish to register pressure, remove the sending unit and thread in a reliable mechanical test gauge to verify the oil pressure.

[chevybones87]

Ok ill give it a shot but not to sound like a dummy but where is the sender and could you describe it I'm new to this. Its a 1980 k10 with the 4.1 i6... Thanks alot guys yall have already helped alot with various other things I've read

[bd]

Located on the passenger side of the engine block and has a single, tan colored wire connected to it.

[chevybones87]

Great thanks alot it was my gauge.. Swapped it out good to go

[bd]

Great!  Thanks for letting us know the outcome.