so, driving my '93 Jeep Wrangler i noticed lately that the oil-pressure goes up to max. when the car gets *low* on oil ...


anyone care to explain?

the car has the 4.0L straight 6, called "High Output" (whatever that means) ...
hauls ass (for a jeep) ...
never had any trouble with the oil pressure, always used to be around the center on the gauge when filled up nicely.
but lately, when the car gets low on oil, the pressure goes to max. on the gauge until i fill her up with oil again, then the pressure drops to normal.

this is kind of counter-intuitive. shouldn't the oil-pressure *drop* when low on oil ???

what am i missing here?
Andy

Andy ..when you figure it out let me know ...or if I figure it out I will let you know !!!! My 94 Wrangler with the same engine does the same thing .....the lower the oil, the higher the pressure !!!!

where are all the engine gurus when you need them ???

Andy

QUOTE (SirAndy @ Jun 8 2005, 10:23 PM)

this is kind of counter-intuitive. shouldn't the oil-pressure *drop* when low on oil ???

Drain out all the oil and see if you still have pressure. If you do, you can save lots of $$ on oil changes

Ok, trying to be serious here...that is quite strange. Maybe there's something flaky with the relief valve for the oil filter.

FWIW, I've known quite a few people who have owned Wranglers built in the early and mid 90's, and all of them suffered through weird electrical problems. One had to have the entire instrument cluster replaced twice b/c of speedo and tach display problems. Another had reverse lights that were always on until reverse was actually engaged. This person also had problems with the air venting system -- moving the little selector lever sometimes worked, sometimes didn't, sometimes selected outputs different from what was indicated (don't know if this is an electric system or not)....

I don't know much about 'em, but from what I do know, that generation of Wranglers were just funky This might just be another quirk that endears them to so many people (not unlike how we celebrate the 914??)

why are you going low on oil to begin with? are you burning too much oil? and i can attest to the electrical problems of wranglers. my 98's speedometer sometimes doesn't work at all, or sometimes the whole dash for that matter. sounds like you probably have a bad sensor. it may freak out when there is low oil and react the only way it knows how.

hmmm, never had any electrical gremlins with that car. gauge works when oil level is good.
a broken sending unit that reads high on low oil level but normal on normal oil level? hard to believe ...

keep 'em coming ...
Andy

QUOTE (mudfoot76 @ Jun 9 2005, 01:57 PM)

FWIW, I've known quite a few people who have owned Wranglers built in the early and mid 90's, and all of them suffered through weird electrical problems. One had to have the entire instrument cluster replaced twice b/c of speedo and tach display problems. Another had reverse lights that were always on until reverse was actually engaged. This person also had problems with the air venting system -- moving the little selector lever sometimes worked, sometimes didn't, sometimes selected outputs different from what was indicated (don't know if this is an electric system or not).... I don't know much about 'em, but from what I do know, that generation of Wranglers were just funky This might just be another quirk that endears them to so many people (not unlike how we celebrate the 914??)

BINGO! Jeep's electricals SUCK big balls....I loev the jeep but they didnt put alot of thought into the electricals. For instance, on my 94 wrangler 2.5L (with 4.88 gears--axles for trade) whenever i would wash the car, the water temp guage (which randomly stopped working) would start working for 30 minutes, fluctuate between normal temp and cold then just die.....

don't worry about it, just DRIVE the damn thing. Instrumentation.....seriously.

pretend like you live in the bermuda triangle, and that it is just normal.

Yet another reason why I prefer CJ's New cars (trucks) SUCK!! Give me rust or give me death

QUOTE (bd1308 @ Jun 9 2005, 03:29 PM)

Instrumentation.....seriously.

as i said, no electrical problems with the car. ever.
all gauges work. always. heater works. AC works. light works.
never had any trouble with the electrical ...

assuming the gauge works just fine, what could cause the oil-pressure to *rise* when the car gets low on oil ????
Andy

QUOTE (SirAndy @ Jun 9 2005, 03:10 PM)

QUOTE (bd1308 @ Jun 9 2005, 03:29 PM) Instrumentation.....seriously. as i said, no electrical problems with the car. ever. all gauges work. always. heater works. AC works. light works. never had any trouble with the electrical ... assuming the gauge works just fine, what could cause the oil-pressure to *rise* when the car gets low on oil ???? Andy

Have you changed the sending unit? Or the gauge? My guess is a bad resistor on the gauge, or the sending unit itself is bad. If you normally read around 40 lbs, that is typically in the middle of the gauge thus sending the needle north when the pressure drops.If you in fact for some reason had an increase in pressure the needle would go down, but since you don't have sudden increases in pressure you haven't seen it drop. Now onto the bridge I have for sale

why do you need a jeep in san fran anyway?

My 91 has a oddity in it also. My gas guage shows 1/2 a tank when its empty.

Now thats not the oddity. I've rebuilt it twice myself and had a jeep pro do it the last time. Still does it.

Its a Jeep thing. Other people don't understand.

QUOTE (TROJANMAN @ Jun 9 2005, 03:34 PM)

why do you need a jeep in san fran anyway?

The Jeep is the only thing thats even close in this world to a 911 for me.

Its been under construction for almost 70 years. Its changed alot but its always getting a little better, and sometimes worse.

Its totally impractical till you own one.

Its a vehicle with soul. Just as much as any porsche.

Its got some oddities, but thats why I love it.

I'll own my wrangler till I'm buried in it.

i loved my jeep....but the porsche started talking to me in the garage and I started to like it....so now i have the 914.

QUOTE (TROJANMAN @ Jun 9 2005, 04:34 PM)

why do you need a jeep in san fran anyway?

oakland, not san fran ... have you been here lately? what they call "roads" around here would pass for a dirt road anywhere else ...

i'll take it up to tahoe in the winter, lots of fun in the snow ...

i can take the hard-top of in the summer ...

and have i mentioned the dirt roads around here?
Andy

Andy

Maybe another possibility is a partially clogged inlet strainer on the oil pump pickup. I know it still seems strange but it might be worth dropping the oil pan and having a look in there. Maybe some sludge in there doing things to your oil pressure.

i love my jeep, and most people DON'T understand.