The oil pressure on start up goes to the far right of the normal range, but once the engine is warm and at idle it goes to the far left of the normal (white) range. This is my first time with a cummins diesel. Is this normal to have such a fluctuation?

2003 Dodge 2500 Cummins. 29k miles approx.

 

Most (all?) the 1 st 24 isb had sender problems DONT REFLASH.. when in doubt hook up a mechanical to verify......replace sender if necessary (If you re flash your gauge becomes a idiot lite)

 

Uhhhh Thumper, read his sig....2003. It is normal. Your gauge reading is what some engineering group decided what you "want" to see in oil psi. The Cummins uses an on/off switch for oil psi. The gauge cluster sees this signal and gives you a gauge reading.

 

I have always had serious time warp issues every since I got here

 

You mean the oil pressure switch is actually an idiot light. So it's normal to fluctuate so much. It never goes in the red, but it's close at idle. as soon as rpm's pick up, then the oil goes up as well.

thanks,
John

 

Yes. The gauge cluster has no idea what oil psi you have, it just knows you have it.

 

Ok, then my next question would be: is there an aftermarket oil sending unit I can attach and Tee off the oil switch, so I can have a real gauge for oil psi at the helm?

Thank You for all your input.

 

Then how does the gauge know that there is higher psi at start up, and lower at idle or when warm, etc. Is it using input from ambient temp sensor, rpm sensor, etc. It would make much more sense to just put a real psi sender, rather than a switch.

 

That's exactly right, but more sense means more money. The best place to plumb in a real gauge is at the 1/8" NPT port directly above the oil filter. A 0-60 PSIG boost gauge works great.

 

...that's exactly how they do it. Eng temp, rpm input. Fredbert has ID'ed the location for an easy gauge tap.