1991Jeep_Man

As the title says, I think its tossing in the towel. Wierd thing is, its only 'failing' mid-range it seems. Meaning, when I start the Jeep and she's cold, the oil pressure gauge reads about 60 psi, which is normal. However, this evening when everything was at op temp, I could not seem to get it to go over 40 psi. At hot idle, I had 22-25 psi, again normal. Accelerating to 1500+ rpm, about 30-32 psi. Normal. But then at 2000 rpm, and even 2500 rpm, the gauge stops at 35-38 psi. It won't go any further.

So, do you all agree in thinking the sender is dying?

If so, what replacement do you recommend, and how is it done?

Thanks!

freegdr

oil pressure will be high at first start motor cold ,after motor warms up oil thins a decrease in pressure will occur this is perfectly normal if a new sensor is on your mind it wont hurt there only like 20 dollars at auto zone

1991Jeep_Man

Yeah, the sensor works when the engine is cold. Cold oil = higher pressure, which is about 60 psi in my case. I'm just trying to figure out if it's possible for a sender to fail mid-range, meaning it won't read a certain input voltage.

As for the A/Z sender, are they good? I've heard some aftermarket senders don't work well with our XJ's.

freegdr

its very possible

1991Jeep_Man

Thanks for the help! So, are these A/Z senders realiable? They have a lifetime warranty, but still I've heard hit and miss reviews. Also, is it hard to replace?

freegdr

its auto zone i dont care to much for them either but its the only place that has it in stock if you can wait order one on line if a better quality can be found,and its very simlpe on the 4.0

00-buck

replaced my oil sending unit a year ago with an autozone unit she still working!

tjwalker

Failure of the sending unit is not uncommon. It is located right above the oil filter. Just unplug the connector, unscrew the old one, screw in the new one, reconnect connector.

I recommend purchasing this sensor directly from Jeep for best reliability/accuracy/mating with your factory gauge. Aftermarket oil pressure sending units are hit and miss, so I won't recommend them any longer. An OEM one is worth the extra $25.