I have a 1994 Dodge Ram 1500 with a rebuild 360 I have a new oil pump in it and the gauge ill read fine for about 5 mins then the light comes on for low oil. I have a new cluster in the truck and a new oil pressure sensor. What is causing it to be dumb

 

Does it drop off, and stay down? Or does it just drop at idle, when engine is up to temp?

Best bet is to put a mechanical gauge on it, and see what it is REALLY doing.....

 

+1 on mechanical Gauge. I have one in the tool box to diagnosing problems like this. If it actually does drop, there may be too loose a fit on bearings.

 

It drop even before the temp goes up. I did hook up a mechanical gauge and it read fine. when u get up in the high rpms the pressure goes up then u let off it drops instantly

 

Pressure increasing with rpm is normal. How low does it drop off to? Mine never gets lower than about 45psi. Dash gauge is on the money with mechanical gauge.

 

Mine sits at 35-40 at low rpms and above 55 at higher rpms or when ever i stomp on it.

 

+1 on the question "how far does it drop?" My pressure drops to 35 when hot at idle and then back up to 65 when at or above 1250 rpm.

 

by wat i meant on my last post was when i do a cold start just about 5mins into is at idle the needle drops showing no pressure, when it the gas just about 1500 rpms the it goes up to normal on the gauge. I wont mind a mechincal gauge but I try to keep most of the orginal equipment in it. the mechinical oil gauge when i hooked it up was reading about 25. I already change to another oil pump thinking it my have been a bad one but it read the same

 

If the mechanical gauge showed no drop, it is more than likely the sending unit. They can be picked up for about 20 bucks from summit. Question, when the pressure drops on your gauge you didn't hear any knocking did you? As long as the mechanical gauge registers pressure I would swap out the sending unit.

 

On cold start the gauge should be HIGH up there, I mean HIGH like 75-100 or more. Make sure you NEVER use fram oil filters. I spend the big bucks on the K&N oil filters. Hope this helps. Take a look at the oil filter thread and do some reading. It will help you pick a an oil filter that suits your needs.