Should my oil pressure gauge ever be this low?
- Thread starter Kathy
- Start date
chattycheech
New Member
I reset the ECU by Disconnecting the battery for 15 min as I forgot to do so after replacing the sensors. That made a big difference. No Check Engine Lights or Irradic Idling (still seems a little high on start up and does fluctuate a few hundred RPM still) HOWEVER, the Oil Pressure is still fluctuating and dropping and bouncing back up quite a bit. I Am beside myself as to what could be causing this problem. The Oil pressure sender is from Napa, so Its NOT Mopar. Maybe its bad, so I guess I have to rule that out. Any OTHER Ideas?? I really hate to replace the Oil Pump since my pressure was really good the TWO times I hooked up a Snap-On Mechanical Gauge and ran it for 20 minutes each time.
C.J. Roberts
TJ Addict
Are you not reading the comments from other posters? IT'S NORMAL!!
If you don't listen to anybody else, listen to Jerry Branford. He has virtually written the book on All Things TJ. He is the living embodiment of Been There, Done That.
TrailYacht
Member
chattycheech
New Member
Wow...Relax Mr. Trail Yacht; What do you have to prove? Let me be more specific. I hardly think its 'NORMAL' for the Gauge to drop to ZERO (not mid-range lows) intermittently, the Red CHECK GAUGES light to come on with a concomitant BEEP BEEP BEEP that all of a sudden started happening that has never happened in 15 years prior??
C.J. Roberts
TJ Addict
In your second post, (the first post I'm quoting), you don't say anything about dropping to zero, the check gauges light, or BEEP BEEP BEEP. You specifically say NO check engine light.
What you describe in that post is, by any definition, normal. You do say that a "my pressure was really good the TWO times I hooked up a Snap-On Mechanical Gauge." Other posters have described the factory gauge/ sender as not particularly accurate. Try replacing the NAPA sender with a Mopar unit. Some owners have also added a separate mechanical gauge for their own piece of mind.
I've BTDT hunting for a problem, (two years and over a thousand dollars for a small evap leak), so I understand the frustration, and only want you to understand the problem so as to fix it.
I thought I read normal for the 4.0 was from 14 at idle to 45 while driving.
I had an XJ that got over 280k on the clock and read around 18 at stop lights
I had an XJ that got over 280k on the clock and read around 18 at stop lights
chattycheech
New Member
Thanks Mr. Roberts. I wasn't being as specific as possible. The YELLOW check engine light I believe was associated with the Bad Coolant Temp. Sensor that I replaced and forgot to reset the ECU. I believe this oil gauge/pressure problem is unrelated, as it started at a separate time, even though I was having them both concomitantly for a short time. The dash light that comes on when the pressure drops all the way to ZERO is actually the Red "Check Gauges" light which has the audible BEEPING when its illuminated. I hooked up the mechanical pressure gauge to confirm or deny whether the pressure itself was actually dropping, which it was not. So, This is why I'm baffled. I was prepared to drop in a new oil pump drive, but don't believe its faulty. My only explanation is that my new NAPA Oil Pressure sending unit is bad.
chattycheech
New Member
Just curious if some can tell me what I should expect the gauge to do if I unplug the oil pressure sensor wire while the engine is running assuming the sensor is functioning properly...
Where is the best place to buy mopar parts online?
Where is the best place to buy mopar parts online?
Last edited:
Brianj5600
TJ Expert
Brianj5600
TJ Expert
While it's no longer the case for all or even many vehicles any more, engine designers sometimes set the cold engine rpms to be a little higher to help the engine warm up more quickly.
chattycheech
New Member
I guess its safe to say that I have offended some folks in my efforts to get some help with my problems. That was not my intention at all. I should have been more specific with my symptoms, but I feel that if someone was genuinely interested in helping me, they would have asked me a few more leading questions in an effort to better understand the situation, rather than keep saying its normal and spelling out the definition of normal. I dont know what that accomplished, but I guess this group of enthusiasts is not somewhere I belong. Since no one is extending an olive branch with my last couple of posts, I am going to bow out and apologize for my insults to you. Thanks for the help.
C.J. Roberts
TJ Addict
I would guess that unplugging the sensor would simply cause the gauge to read zero. As for online parts, look at www.wermopar.com, www.moparpartswebstore.com, or www.wholesalemopar.com.
CUEngineer
New Member
you guys do understand that the long pole warming up (even when it is hot outside) when you start an engine is not the oil being run through the engine. You're waiting for your piston rings to properly expand and fill the gap and make a proper seal in your combustion chamber. There is no time rule you should do it based on RPM drop only.
19sahara97
New Member
I’ve checked out this thread before as I have a 97 sahara that’s new to me as of about a year and a half ago. The pressure did what the op’s was doing but I wrote it off as normal because of the replies here. Recently however it was dropping much lower and not even coming back up to 35 at speed. I ran seafoam through the crankcase for a couple hundred miles and then changed the oil. The pressure is now much more consistent, maintaining between 35 and 40. I’m so happy with the results I thought I would share with anyone else suffering from low pressure. The seafoam really cleaned it out.
That is also temperature related. At 40 below and not plugged in every vehicle I've owned starts with no oil reaching the tappets. You listen to the tappets clattering for a minute or two even if you use synthetic oil. Then you drive a couple of blocks on the tire flat spots before the rubber starts flexing and the ride smooths out. And another 5 miles before you feel any heat from the defroster.
Living in the arctic and having several vehicles survive 300K miles with no issues, I'd say the engine warms better under way than idling. Not freeway speeds but start it and pull away slow until everything warms up. Tires, shocks, all the fluids need to warm up, not just the engine.
LONGJP2
TJ Expert
Isn't this true for the other gauges as well. They stay centered; only moving to the right or left when something is not normal?
Yep, the gauges on modern cars are for entertainment value only, lol.
It fixed one problem, people complaining about gauges moving, and caused another. Now they see the needle move and think it's fine as long as it doesn't go too high. But for coolant temp anyway if that needle starts to go up you're in trouble.
Get one of those Bluetooth OBD2 code readers connected to your phone and monitor the actual sensor data if you want to see what's really going on.