My truck was sitting for 10 months with a bad fuel pump. It is now replaced and running. When it started, it had very high oil pressure, around 70 psi. After warming, it dropped to 45. It used to idle at 20 psi, in gear. Oil pressure switch was replaced 9 months ago, so it has no running time on it.

The oil pressure switch is evidently running the fuel pump, for it won't shut off. The truck starts and runs without a relay.

Is it possible to over tighten the oil switch and cause this problem, or do I just need to change the oil?

Thanks for any suggestions.

 

I would change the oil and filter anyway. I would also check the wiring around the oil pressure switch to see if there is any damage to any of the wiring or electrical compnents.

 

The oil pressure senders on the tbi's are notoriously unreliable. Check with a manual guage.

 

It appears as though the oil change combined with a little leveraging on the oil pressure sender fixed the issue. It was a new sender, just hadn't been tested since the truck wouldn't run. I'll let you know if it starts acting up again.