I have not owned my diesel but a year so excuse the question. I did a search also and I did not find the answer I was looking for. I have an 04.5 and when it is started and running about 1000 or more rpm I have normal oil pressure. Middle of the raoad on the stock gauge so about 40. When I stop the pressure drops close to the bottom of the good area. This just started not too long ago. Do I have something going out? Is the engine wore out? It does have over 100 on it and I had some fuel issues where we replaced the injectors and everything else. Please let me know your thoughts.

 

It's unlikely there's anything wrong with your engine or oil pressure, unless you ran it a long time with severe oil dilutuion from that injector problem. Thread a test gauge into the spare port on the filter head to check it. Try cleaning the connection on the oil pressure sender to see if that puts the dash gauge back where it should be.

 

NEVER trust the factory gauge the sending unit for that gauge has a 7 psi sender. meaning at 7 psi the gauge will read normal. the ecm tells the gauge what to read depending on engine temp,load and rpm's. get a manual oil pressure gauge. at highway speeds with hot oil I have 50 to 60 psi and cold oil can be as high as 80 psi. Rob

 

Yea, the factory gauge is fake. I installed a real oil pressure gauge soon as I found out.

There algorithm isn’t too bad, for it generally has the right idea, but there are times when the poser doesn't match the real gauge.

I see about 80 or so after a cold start and around 25 at idle when she’s warm.

The fake gauge shows pressure before the real gauge does. Once I installed it I started waiting a bit longer after startup before moving the truck.

 

There's nothing wrong with the factory gauge and it will NOT read normal (middle of the scale) at 7psi. It is designed to show an elecronically sampled reading for smoother appearance. Changes are slower to appear and less apparent due to it not being a full-sweep dial (smaller scale).

If there's anythng wrong with yours it's most likely related to the wiring/connections to the sender/ecm.

The 7psi pressure switch is for the idiot light, not the gauge.

 

My gauge reads ~8psi, hot idle with a load.

Tony

 

So is there a better place to put a new mechanical gauge on the engine?

 

I've read that if there is at least 6 psi it will read normal, if below 6 psi the ECM will position the needle in the red zone, light the check guages light, and sound a tone, I'll post up the info from the service manual when I get home if you'd like.

 

Yes please, I'd really like to see that!

 

I hope you are mistakenly talking about fuel pressure and not oil pressure???

8psi of oil pressure isn't a good thing.... EVER.

 

Heres what the 05 manual says, I guess it doesn't specifically say its completely fake but it is a smart assumption given what they tell you IMO. Notice what it says about the SRT-10, makes me think that one is actually functional.

 

You are making some assumptions out of that extremely vauge description of the gauge operation. It clearly fails to fully describe what is actually going on, or even explain why there is a difference in the SRT10 variant. I can tell you from experience in some activities with an oil pressure-related situation, there is alot more going on there than what you are reading out of that description.
What this doesn't tell you what is defined as "near" the middle and that the ECM is constantly sampling the pressure reading and comparing it over time, returning an appropriate gauge reading. Otherwise you'd be getting a check engine light and alarm chime every time you start the engine. The more times the sample varies in greater amounts, the more the gauge pushes away from "near" the center of the scale. That center portion or ""near" normal reading on the scale covers approximately a 50psi range, with about 80psi leaning towards the right and 30psi leaning towards the left. I guarantee you if it gets below 20 or so, you will see the gauge reading low, or at least obviously lower that you normally remember it. Where it normally rides may become variable over time due to resistance buildup in the electrics or degradation of the gauge itself. It ain't gonna sit there in the middle and all of a sudden drop off because you just lost all oil pressure. Of course, it would do that if it actually happened, it would take 3-5 seconds instead of the instant reading you'll see on a mechanical or conventional electric gauge.

This is just the way it's done nowadays with digital stuff, and there's nothing fundamentally wrong with it.

 

Well either way it seems the general consensus on this site is that it is completely fake, maybe just a bad rumor, I don't know. I would really like to find some real evidence to put it to rest, I hate giving bad info.

 

Just put on a real gauge and compare it to the stock gauge. That'll tell you tons. The pressures from my Autometer and the stock gauge are NEVER the same. I trust Autometer.

 

My guage does the same thing. When first start, it will go to the middle and stay there. After warmed up, when driving, accelerating, etc. it will move to the middle. At idle or coast, then it will drop to the bottom of the "normal" range.