02 WJ gauge reads zero oil pressure

Tradarcher

Well-Known Member
Joined
Mar 20, 2005
Location
Creedmoor, NC
Daughter's 4.0 only made it 1/2 mile up the road this morning before gauges light came on. It leaks some oil so I thought maybe I was overdue in changing it. Changed it this evening and it is still reading zero. After I changed the oil it bumped up for about 1 second and then back to zero. It's pegged left and doesn't move at all. Before this it read straight up at idle and a little high when driving.

Have you ever seen a complete failure of the oil pump so that it didn't pump any oil at all? Is there any way to verify that it is pumping oil? My ears might be playing tricks on me cause I think I hear a little top end noise that I didn't hear before.

I am aware of the sending unit issues and will be checking it as well. I've seen sending units that waver up and down with the engine rpms and I have cleaned them out with carb cleaner and put them back in and that fixed it. For zero oil pressure to suddenly show might the diaphragm be completely blown out?

I don't have an external oil gauge to work with.
 
Just noticed that the rocker arm visible through the valve cover was dry but became full of oil when I started motor. Oil appeared for be moving when looking through valve cover. When motor is turned off i can hear oil draining back into the pan.
 
only time any 4.0 I've had has read 0 oil pressure was when sending unit was bad or when I blew a piston rod through no4 cylinder but it still had pressure just only went up when in the throttle, and when I busted oil pan in mtn city and lost all my oil...
 
Oil in the connector. Diaphragm must be blown.
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Did all the oil come out of engine was it thick? I've had a oil sludge blockage on a GM 3.8 from using crap oil had to use pressure to blow oil passages free to drain all the oil!!? Just a thought
 
It's the sending unit wife's 4.7 wj does the same thing been like that for 6 mouths I am just to lazy to change it

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When I pulled the connector I heard a little pressure relief noise so I figured that was the problem. Oil is all over the connecter and the inside of the sending unit connections. Not to hard to get to unlike a crank sensor. Hope to have one in it tomorrow if I can find a good one locally.
 
Yahtzee!
 
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