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04 Ram, 4.7L, zero "oil pressure"

32K views 10 replies 5 participants last post by  Gatorlawman 
#1 ·
Hi people.

I've got an 04 Ram with about 30k miles on it. Mobil 1 oil since new. I go to start the truck up on saturday and drive it out of my driveway and around the block, while I jockey the position of a couple other cars in my driveway.

When I'm done, I notice that the beeping I've been hearing is not solely due to me not wearing my seatbelt, but also that there is a "check gages" light on and my "oil pressure gage" is reading zero (at this point, I've driven the truck about 1/3rd of a mile while cold, engine sounds normal).

I stop the engine immediately, and check the dipstick. It reads a little low, so I dump a quart in. Start the truck up and still no "oil pressure" (engine still sounds normal).

So, I immediately shut it down, and scrap the trip that I had planned (going to pick up some furniture).

Anyhoo, some internet research shows that there are definitely oiling problems with these engines (plugged pickups, bad oil pumps), but also some oil pressure sending unit problems. I'm hoping it's the sender, obviously.

So my question is, is the oil pressure sender that is shown in the service manual I obtained the only one? It's shown to be right near the oil filter. Additionally, the manual claims that this sender is a variable voltage sender, which outputs a different voltage based on the actual oil pressure. However the behavior of the "gage" lead me to believe (and some internet research seemed to confirm) that the "gage" was actually just an "on-off" display (basically and idiot light in gage disguise). If this were true, then why would the oil pressure sender be a variable voltage output? Perhaps the ECU converts the voltage to a binary output?

Regardless, of all of this, is this oil pressure sensor by the oil filter the only one? Any simple way of testing it, other than hooking up my multimeter and some compressed air?

Any info greatly appreciated.
 
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#2 ·
Welcome to Dodgetalk!
Yes, there is only one pressure sensor & it's near the oil filter. Output of the sensor is variable, you can pull up the sensor output on a scan tool and read actual oil pressure. The signal to the instrument cluster is filtered to eliminate the large variation you would typically see in cold vs. hot oil & high speed vs. low speed operation. All automakers do this now because customers tend to freak out if the oil pressure is to near the high or low point on the gage. So to answer your question, yes it's a step up from an idiot light. The sensor probably went bad, internally there is a plastic disk that eventually fatigues from pressure pulses leaving the unit "waterlogged".
 
#4 ·
Happen to me today!! Coldest outside at 8... I run my truck for about 15 mines to warm up before leaving the driveway and I notice oil pressuer is at 0!! I freak out and i wasnt sure what is problem with it. I turn the engine off and start it again and check gage and oil pressure went back on normal. Why is that?
 
#5 ·
I'm having the same problem now. Replaced the sensor 2 times and still does the same
thing. check gauges light comes on and the pressure drops to "0" and when the light goes out it returns to normal. Today it stayed on "0" for about 20-25 miles. My temp never moved to hot. I can't figure it out.
 
#7 ·
Found the Problem

Well, there's your problem right there!



Apparently something chewed through the cable (oil pressure sending plug), or it got caught in something and shredded up.

*note - the site won't let me post a picture of the problem because I don't have 5 posts - so ignore next 2 posts.
 
#11 ·
After reading many problems with the Chrysler v-6 problems in early Sebrings, it was suggested to put a real oil pressure gauge to read the pressures. That was the only way to know if the clogging was starting and to try and fix it before the engine burned up. Might be a good idea for the 4.7
 
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