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I am sure this is a noob question, but none of my other diesels have done it and none of my co-workers seam to do it. When it is cool outside, truck starts just fine but as soon as I drive off it seems my oil presure is almost pegged, I normally let it warm a little befor I leave. The presure still does not come down untill it is almost compleatly up to temp. I try to baby it untill the presure comes down. Do I need to?
 

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what weight oil are you running? Maybe it's too heavy and doesn't flow as well as it should. I notice mine running a little high when it's cold (less than 10F) too but not pegged.
 

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what weight oil are you running? Maybe it's too heavy and doesn't flow as well as it should. I notice mine running a little high when it's cold (less than 10F) too but not pegged.
factory oil from dealership, it only pegs while driving untill it warms up than back to norm. This week is the first time my truck has seen below 10 and hopefully the last.
 

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well, I guess i don't have a good explanation as to why it would be pegged so high. My only experiance is the gauge being at about 3/4 of the way up when it's cold and then settling back to just over half of its range (I think about 40psi). Maybe someone else will chime in here.
 

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At what RPM does the gauge peg? And by peg, I assume you're saying it goes ALL the way to the right and could go no further, correct?

FWIW, I don't wind my engine out until it's up to operating temperature, keeping my oil pressure needle between the middle mark and the mark just to the right of it (high end of normal). I'm also running Rotella T6 5w40 synthetic.
 

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with the 2003 and newer diesels, the oil pressure you see on your gauge is computed oil pressure, not your actual. Hook a manual gauge up to where your oil pressure sensor is and then you will have a much better idea.
 

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with the 2003 and newer diesels, the oil pressure you see on your gauge is computed oil pressure, not your actual. Hook a manual gauge up to where your oil pressure sensor is and then you will have a much better idea.
Ummmm, no? Have any references to back that up? Any idea how the ECU would "compute" oil pressure without actually knowing what viscosity oil was being used?

It's true that the oil pressure gauge is CONTROLLED by the ECU, based on the reading it gets from the oil pressure sending unit, but it is not "computed" (aka "made up").
 
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with the 2003 and newer diesels, the oil pressure you see on your gauge is computed oil pressure, not your actual. Hook a manual gauge up to where your oil pressure sensor is and then you will have a much better idea.

^^This is correct, the in-dash factory oil pressure gauge is a fake on the 2003 & newer Dodge Cummins trucks.
All you have to do is hook up a temporary oil pressure gauge & compare.

I have Autometer oil pressure & water temp gauges.
The factory water temp gauge is not really a fake but it's very non-linear.
Water temp swings from 170F-220F barely move the factory gauge.

My Brakesmart Tow controller displays voltage & it shows that the factory voltmeter gauge is calibrated very strangely.
Small voltage changes around 14V make for large swings of the factory gauge.

I don't rely on the factory gauges at all anymore.
 

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^^This is correct, the in-dash factory oil pressure gauge is a fake on the 2003 & newer Dodge Cummins trucks.
All you have to do is hook up a temporary oil pressure gauge & compare.

I have Autometer oil pressure & water temp gauges.
The factory water temp gauge is not really a fake but it's very non-linear.
Water temp swings from 170F-220F barely move the factory gauge.

My Brakesmart Tow controller displays voltage & it shows that the factory voltmeter gauge is calibrated very strangely.
Small voltage changes around 14V make for large swings of the factory gauge.

I don't rely on the factory gauges at all anymore.
Not saying what you see is false, but I can't help but notice neither of you have a 6.7. I have a 6.7 with the Insight CTS and based on what the Insight shows compared to my gauges, they're spot on. ECT on the Insight matches the gauge perfectly. I have no reason to think that the oil pressure gauge is a "dummy."

My previous truck, a 2005 Titan, basically did EXACTLY what you are saying your truck does. I had a Bully Dog GT on the Titan and both the coolant and trans temperature gauges were very non-linear, basically they were partial dummy gauges that would barely move if the parameters were in the "normal" range and would only move at the extreme ends of the scale.

Seeing as this is the 6.7 section, I'd like to see some references and experiences with the 6.7, not the 5.9. :thumbsup:
 

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I am just going off of what my local cummins and dodge dealers informed me about 2003 and newer dodge cummins, 5.9 or 6.7
either way, it is not a bad idea to hook up a manual gauge and double check.
 

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Ummmm, no? Have any references to back that up? Any idea how the ECU would "compute" oil pressure without actually knowing what viscosity oil was being used?

It's true that the oil pressure gauge is CONTROLLED by the ECU, based on the reading it gets from the oil pressure sending unit, but it is not "computed" (aka "made up").
This is hilarious....AFAIK....all the sending units are input to the ecu, then extrapolated to what the engineers calculated the gauge reading should be....they did know best, now didn't they??? bunch of dumba**'s is what they are....
 

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This is hilarious....AFAIK....all the sending units are input to the ecu, then extrapolated to what the engineers calculated the gauge reading should be....they did know best, now didn't they??? bunch of dumba**'s is what they are....
Not quite sure what you think happens in the ECU. Some vehicles do have dummy or partial dummy gauges based on what's programmed into the ECU, others do not. Based on what I've seen, the oil pressure gauge (and other gauges in the cluster) in the 6.7 is not calculated or extrapolated using some magic formula. The sending unit sends a voltage signal that's calibrated based on PSI, the ECU translates that into a signal to the gauge since the gauge has a motor whose position is controlled by the ECU, it's not simply a gauge that's been calibrated to the voltages supplied by the sending unit like the older vehicles.

You knew that, right? That the gauges in the dash cluster are operated by stepper motors? Stepper motors require a microcontroller...guess what the ECU is.

If not, then I guess you really have no place trying to insult someone that has a better understanding of the system than you do.
 
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My understanding was that the 6.7L engines only had an oil pressure switch like the 5.9L trucks & that OBDII monitors wouldn't display oil pressure readings.


Yahooligan, does your Edge OBDII Insight give actual oil pressure readings?
 

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My understanding was that the 6.7L engines only had an oil pressure switch like the 5.9L trucks & that OBDII monitors wouldn't display oil pressure readings.


Yahooligan, does your Edge OBDII Insight give actual oil pressure readings?
It doesn't, but it doesn't show all the OBDII PIDs that are available, either. There are a number that are missing.

Also, there are a couple of P-codes for the oil pressure sensor that do apply to the 6.7, I don't know if these apply to the 5.9 or not:

P0521 Engine Oil Pressure Sensor/Switch Circuit Range/Performance
P0524 Engine Oil Pressure Too Low

I could see only P0524 if it were a simple on-off switch, but P0521 tells me it does more.

Those of you with a 5.9, does the gauge actually change with RPM or does it always stay steady?

It seems like an awful lot of work to make the oil pressure gauge on the 6.7 be fake but perform like a real gauge that does have different positions based on cold or hot oil temp as well as RPM. Sure would be simpler to just translate the sensor reading into a signal to be sent to the stepper motor in the gauge cluster like the ECU does for the other gauges.
 
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If your Edge Insight doesn't show oil pressure, it is highly likely that the 6.7L does not have an actual oil pressure sensor.

The definitive proof for the 5.9L engines was the wiring diagram that showed that the oil pressure sensor was actually a switch.

As I mentioned for my 5.9L, I have an Autometer oil pressure gauge. It's tapped into one of the oil filter head ports.

The in dash gauge has a small range while the Autometer gauge shows full range.

For example, when my engine in cold my Autometer gauge shows 75PSI while the in dash gauge shows a little high.
When my engine is warmed up my Autometer gauge goes from 20PSI at hot idle to 70PSI at higher RPM. The factory oil pressure gauge barely moves.
 

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If your Edge Insight doesn't show oil pressure, it is highly likely that the 6.7L does not have an actual oil pressure sensor.
The Insight is known to not show a number of PIDs that do exist, the lack of an oil pressure PID means nothing.

The definitive proof for the 5.9L engines was the wiring diagram that showed that the oil pressure sensor was actually a switch.

As I mentioned for my 5.9L, I have an Autometer oil pressure gauge. It's tapped into one of the oil filter head ports.

The in dash gauge has a small range while the Autometer gauge shows full range.

For example, when my engine in cold my Autometer gauge shows 75PSI while the in dash gauge shows a little high.
When my engine is warmed up my Autometer gauge goes from 20PSI at hot idle to 70PSI at higher RPM. The factory oil pressure gauge barely moves.
I'm not questioning the 5.9, I'm saying the 6.7 appears to be different. Couple that with the fact that you can easily find a replacement oil pressure switch for the 5.9 all the way up to 2006...but there's a mysterious lack of one for the 6.7.

All I'm asking is for someone with a 6.7 to tell me they have a mechanical gauge installed that doesn't match the dash gauge, then I'll shut up. :D Everything I can find, and everything stated here, relates to the 5.9 and yes, they use a switch.
 
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Don't be confused yahooligan....the engineers that followed the direction of their superiors are the ones I have a problem with....way to many guys have put real guages on their rigs and found the stock ones to be pretty much junk....6.7 or 5.9 no difference..sounds like some other posters got your interest up enough to dig deeper and prove my point
 

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Don't be confused yahooligan....the engineers that followed the direction of their superiors are the ones I have a problem with....way to many guys have put real guages on their rigs and found the stock ones to be pretty much junk....6.7 or 5.9 no difference..sounds like some other posters got your interest up enough to dig deeper and prove my point
Ultimately that's always what I'm after, verifiable proof or references, though sometimes my instigation may not make it look that way. :D Everyone can afford to learn something new, nobody knows everything about everything.

In my field, "because I said so", "I've been doing it this way for years", etc doesn't qualify. :D So I'll keep looking until I find the truth or someone gets fired up enough to provide data to back up their claims. If all I get back are insult attempts then I think it's pretty clear what the other person is full of, and it's not knowledge! :thumbsup:

I'm hoping Edge will augment their EAS with an oil pressure sensor so I can get an accurate readout on the Insight. They say they'll be adding more accessories (sensors, etc) when they can.
 
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