Jump to content
Mopar1973Man.Com LLC

  • Welcome To Mopar1973Man.Com LLC

    We are a privately owned support forum for the Dodge Ram Cummins Diesels. All information is free to read for everyone. To interact or ask questions you must have a subscription plan to enable all other features beyond reading. Please go over to the Subscription Page and pick out a plan that fits you best. At any time you wish to cancel the subscription please go back over to the Subscription Page and hit the Cancel button and your subscription will be stopped. All subscriptions are auto-renewing. 

Oil pressure gauge

The_Hammer
 Share

Recommended Posts

CSM

CSM

Posted
Posted
3 minutes ago, Nekkedbob said:

It is not a dummy gauge but the dash assy. is not high quality gauge set. What you see in mopar1973mans video is the voltage regulator on the back of the dash assy that has gone bad or a high resistance ground to the dash. The biggest problem with our dash is it takes a analog signal from the sensor and converts it to digital in the ECM and or PCM and then decodes it back to a analog value for the gauge set and if  tolerances are not kept very small (meaning more expensive ) you get just what we see. This is the biggest reason for the aftermarket gauge industry is that mfgs. put gauges that barely qualify as a useful gauge. Why do you think that you cannot find any accuracy specs for there stuff and they don't put but very few markings other "operating range". Many years ago I found the accuracy spec for speedometers ( I wish I could remember where ) from the D.O.T. and they only need to be within +or - 10 percent.

So, why does most everybodies truck do that when we fool the coolant sensor?  They are separate systems and could not be causal.  

  • Like 2
Link to comment
Share on other sites
dripley

dripley

Posted
Posted

I have to add this even if it cost me a dollar. When I took off from lunch today on a somewhat warm engine my temp spiked a little, around 193 just as I came up on a stoplight. When I stopped I guess the t stat had just opened and the temp dropped to 177, per my scan gauge. I happened to look at the oil pressure gauge and watched it rise slightly as the temp dropped. Then temp then leveled out and the oil pressure dropped slightly. That is the first time I have ever seen that. But it is the first time I ever watched them both to see if they were interacting with one another. I am going to have to watch them closer and be sure it was not just a fluke. I am just not thinking the oil pressure would change at those temps at idle.

Link to comment
Share on other sites
TFaoro

TFaoro

Posted
Posted

Everyone who can fool the coolant temp watches this happen. Dummy gauge. 

To the OP, if the sensor is in fact a pressure transducer and you could find the voltage range, in theory you could set up a system to read the pressure and display it in psi. I have done this in labs, but I don't think it's worth it in this application. If you are worried you should just pick up a mechanical gauge :thumbup2: 

  • Like 2
Link to comment
Share on other sites
  • Owner
Mopar1973Man

Mopar1973Man

Posted
  • Owner
Posted (edited)
11 hours ago, Nekkedbob said:

What you see in mopar1973mans video is the voltage regulator on the back of the dash assy that has gone bad or a high resistance ground to the dash.

There isn't any voltage regulator on the cluster like old school. There are fully digital stepper motors commanded by CCD network data sent from PCM (fuel  and volt gauge), ECM (tachometer, oil pressure and coolant temperature) and ABS (speedometer) computers. That why to test the cluster you hold the trip pin down and turn the key on look for the word CHEC in the odometer window and release. This fires the cluster computer in diagnostic mode to test all gauge functions and spit out any error codes at the end.

So as for the weird oil pressure gauge behavior that function of one of the updated flashes that Dodge created. Like another one I've seen too is once the voltage hits 12.00 exactly the voltage gauge drops to 8 volts and chimes the CHECK GAGE light. Even though the voltage isn't 8 volts it's 11.99 volts and falling.

All data to the gauges is delivered on two wires. So basically in a nutshell the cluster is its own standalone computer.

http://articles.mopar1973man.com/images/general/ccd/CCD-Network-Wiring.jpg

Edited by Mopar1973Man
Link to comment
Share on other sites
The_Hammer

The_Hammer

Posted
  • Author
Posted
11 minutes ago, Mopar1973Man said:

I'm referring to 98.5 to 02 cluster and the oil pressure gauge issues.

94-98 clusters should be oil pressure sender to cluster direct wired. Still in all I would still test with a mechanical gauge.

That's the plan, if for nothing else but peace of mind. 

Link to comment
Share on other sites
  • 3 months later...
  • Staff
AH64ID

AH64ID

Posted
  • Staff
Posted

AFIK all 1st and 2nd gens have oil pressure senders and not switches; however, there is a flash for the 24V crowd that turns the actual oil pressure gauge into a 3rd gen dummy gauge. IIRC any 24V with the latest software will get this "feature". Flashing your truck with a Smarty, and possibly other programmers, will get you the latest software. 

 

 

So you guys are all correct. Some of your gauges work and some don't. 

 

AFIK the dash gauge on all 12V's works properly. 

Link to comment
Share on other sites
  • Owner
Mopar1973Man

Mopar1973Man

Posted
  • Owner
Posted
10 minutes ago, Me78569 said:

I think the switch vs actual gauge is in the PCM not the ECM., 

 

Actually ECM.

 

PCM does nothing with the Oil Pressure value. The ECM reads the data and transmits the data on the CCD Network. It's up to the Instrument cluster to listen for the data and display the data as the cluster is programmed to. PCM doesn't have any connection to the sender so it can't process the data.

 

 

Link to comment
Share on other sites
GSX455

GSX455

Posted
Posted (edited)
20 hours ago, Mopar1973Man said:

OBDII code reader and use the ERASE feature. There is no other way to erase codes. Not even disconnecting the batteries will work.

Well, I turned the key on and erased the codes with the OBDII tool; as I drove the truck, the Check Gages light, came on, I cleared while it was running, and the light is still on, maybe I bought a bad pressure sensor, or could it be the harness pigtail?

Edited by GSX455
Link to comment
Share on other sites
 Share
Go to topic listing
×
×
  • Create New...