So I bought my 2000 XJ Sport last summer.

I took it in for an oil change the other day for it's first oil change since I got it and now my oil pressure guage rides at 80 when I start it after it sits in the cold for long periods of time. I checked the oil and it was in the safe area on the dipstick. The guy did mention that the oil was in bad shape, even though it had only been something like 3000 miles since the last change.

I can run it for 10-15 min and it stays at 80. Let it sit for like 10-15 min start it again and it will go back to normal readings of 20ish.

I am thinking maybe the sending unit or something of the likes. Just looking for any other ideas to look into.

Thanks for your help! You guys always have good answers.

 

The pump has an internal bypass that opens at 75psi. I'd suggest a new sensor.

 

Not that it hurts having a high pressure for 15 minutes...
anyway how cold does it get in the morning where you are? what kind of oil are u using?

 

x2 check the pressure manually if you have a gauge.

 

My oil is black like tar after "only" 3000 miles. It's nothing to worry about. As for the pressure, I would bet that your sending unit is toast...

 

If you're oil is getting that bad after only 3,000 miles I'd suggest that your car is running very rich or there's a problem with your air filtration, and IMHO is something to worry about. Do you get poor fuel economy too? These things aren't diesels, and the oil shouldn't be black after just 3k miles. My oil is what you'd expect in any gas vehicle after 3k miles, but I only have 90k miles on my Jeep too.

 

My jeep is running perfectly, good fuel economy (low to mid 20's mixed driving...), the filter is good (it's a K&N that I clean regularly), there's no coolant issues (like coolant getting in to the oil), compression is good...

It's just they way things work in the desert, we drive in dust all day long, every day, and it's flipping hot more months than it's not in the year. My jeep only has 160,000 miles on it, but I drive it hard.

It's the same with all my other vehicles, that's just the way they are some times...

 

It has 10w30 in it.

I am going to swap the sending unit.

Its been cold here in the mornings 20's-30's. The thing is it runs at 80 until you shut the car off and let it cool. They other night I drove 40 min with it just sitting at 80 the whole time.

 

Mines runs at about 60 when accelerating or highway speeds then drops to about 20 at idol. I thought mine was a bit high too. What's the normal PSI range?

 

My jeep is running perfectly, good fuel economy (low to mid 20's mixed driving...), no hesitation or stumbeling, both oil and air filters are well maintained, there's no coolant issues, compression is good...

It's just they way things work in the desert, we drive in dust all day long, every day. My jeep has 180,000 miles on it, and with 4.56's and 33's runs up handy 3000rpm 8 hours a week.

It's the same with my WJ wich never leaves the pavement and only turns 2200rpm on the highway.

Additionally, oils contain detergents... the oil should be black if it's doing it's job.

 

From FSM:

accidentally had "PSI" highlighted...

 

Did you get your sending unit swaped? Did it fix it? Mine is doing the exact same thing. Just started last night, drove it home and parked it. If that didn't fix it where are you going from there?

FrankZ suggested that it's likely your sending unit because of the bypass in the oil pump. I agree with him but suppose the bypass was faulty, could cause the issue as well? I'm thinking of buying the sending unit on my way home from curch this afternoon.

Thanks guys for all of your imput you not only helped jfgreco but likelly me as well!

 

I went ahead and replaced the sensor. Sure enough everything is back to normal. Thank you again for you help guys!