Re: re:oil pressure
 

Jbs,
Here's what I posted a month or so ago. It's still working great.

(old post below)
97 TJ 4.0 85,000 miles

My oil pressure would momentarily drop to zero sometimes when slowing to a
stop.
The check gauges light would illuminate and the warning beeper would beep.

I know this problem has been discussed on this newsgroup before.
What I found out (below) should help those still having the problem.

It happens so fast sometimes that by the time you hear it beep the oil
pressure is already back up to 20 or so.

So, I find an old aircraft oil pressure gauge I have laying around and I
take it to work and check it against a test gauge we use. It's right on. So
I install a tee so I can screw in the gauge and the sender and fire up the
engine. It turns out the TJ's gauge reads 10-15 psi. lower than I actually
have. The TJ's sender sends it's signal to the computer and this signal is
"adjusted" and sent to the gauge. I think the computer was seeing the oil
pressure dropping and would actually make the gauge continue to show a drop
for a couple of seconds after it started to rise.

Anyway, I order a new oil pressure sender from AutoZone for I think $29.
Stealership wanted $85.
By the way, AutoZone calls it a pressure "switch" so don't let that fool
you.
It comes in and looks just like the old one. I install it and presto, I'm
good to go.
It's reading 10 - 15 psi higher than the old gauge did. And I haven't seen
the oil pressure go below 20 psi.

My oil pressure reads 50 at highway speeds now. It was 40.
I have a factory service manual and it says the minimum oil pressure is 13
psi @ 600 rpm.
And the maximum is 75 psi @ 1600 rpm or above.
I've heard a good rule of thumb is you need at least 10 psi for each 1,000
rpm.

Just wanted to share my this with you guys. This little nagging problem is
now gone.

Mark


"smit" <noveta@shaw.ca> wrote in message
news:QICYa.669962$3C2.15781992@news3.calgary.shaw. ca...
> My 97 jeep tj after driving for awhile, when you idle the oil pressure
> gauge drops to 0 and sets off the check gauges light and alert bell.
> I'm wondering if anyone else has experienced this problem and or know
> what to do about it
> Tks Jbs
>