oil pressure gague pegged all the time?
#1
Junior Member
Thread Starter
Join Date: Jan 2011
Location: Milton WA
Posts: 43
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1999
Model: Cherokee
Engine: 4.0
oil pressure gague pegged all the time?
bought a 99 cherokee classic last month, the oil pressure gague in the cluster is pegged all the time (shows 80lb pressure) weather the engine is running or not. does anyone know the nominal resting resistance of the oil pressure sending unit is so that i can check to see if the sender is nuked like on a chevy or VDO brand gague, if there is no wire hooked to a VDO the gague will pegg and also if the sender is toast. if the resistance checks out it'll probably be the connection in the dash or somewhere along the circuit, and also what is the average running pressure range of a 4.0?
#2
Senior Member
Join Date: May 2010
Location: MI 48642
Posts: 882
Likes: 0
Received 1 Like
on
1 Post
Year: 1996
Model: Cherokee
Engine: 4.0
EXACT thing happened to me. I just replaced the sending unit and it was good to go. I was very confused why it stayed pegged even after disconnecting the wire also. I had managed to crack the plastic from the metal during an oil change and the thing was pegged no matter what I tried to fix it.
I know you want to diagnose it first, but the part is $20 and not worth testing, imo.
Just make sure you get the sending unit, some places try to sell you a part that looks identical but is a (switch?) that goes on the other side of the engine.
Edit: the oil pressure should run between 40-60 when heated up, and can drop to about 20 at idle.
I know you want to diagnose it first, but the part is $20 and not worth testing, imo.
Just make sure you get the sending unit, some places try to sell you a part that looks identical but is a (switch?) that goes on the other side of the engine.
Edit: the oil pressure should run between 40-60 when heated up, and can drop to about 20 at idle.
Last edited by Fsher21; 01-25-2011 at 07:39 PM.
#3
Junior Member
Thread Starter
Join Date: Jan 2011
Location: Milton WA
Posts: 43
Likes: 0
Received 0 Likes
on
0 Posts
Year: 1999
Model: Cherokee
Engine: 4.0
totally awesome thanks man, yea since i bought my xj i figured it was the sending unit but $20 is cheap, thanks for the average running pressures too. the other paret "switch" must be for an idiot light or buzzer.
#4
Senior Member
Join Date: May 2010
Location: MI 48642
Posts: 882
Likes: 0
Received 1 Like
on
1 Post
Year: 1996
Model: Cherokee
Engine: 4.0
yeah I learned the hard way, bought the switch and it fit in perfect, wire plugged right in, but my pressure stayed pegged. I was scratching my head until i came here and someone told me the possible mistake. So i paid $20 twice lol
#6
CF Veteran
Join Date: Nov 2010
Location: In the middle of Minnesota!
Posts: 5,804
Received 99 Likes
on
88 Posts
Year: 1999
Model: Cherokee
Engine: 4.0
I've had best luck with the sending units directly from Jeep. Some (not all) aftermarket sensors are a bit off in accuracy and not long in the longevity department. Worth the extra $20 in my opinion.
Oil pressure spec for the 4.0 is as follows:
*Not less than 13 psi at HOT idle
*Between 37-75 over 1600 rpms
Good luck!
Oil pressure spec for the 4.0 is as follows:
*Not less than 13 psi at HOT idle
*Between 37-75 over 1600 rpms
Good luck!
Thread
Thread Starter
Forum
Replies
Last Post
Blackcherokee290
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
27
07-26-2022 07:52 PM
ammonllewis1
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
9
08-31-2015 11:27 AM
EBowen95
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
49
08-25-2015 08:44 PM
jeeper albert
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
3
08-24-2015 01:17 PM
kjdad
Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go here
12
08-21-2015 08:11 PM
Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)