When mine went last summer it was as simple as the thin paper gasket
between the pump and the block blowing out - but that left me with
about half pressure, so I made it home. Outside possibility would be
a high pressure relief valve stuck open or with a collapse spring. I
would try pulling the distributor as others suggested first but you're
probably going to have to pull the pan anyway. Good news is that it's
a one bananna job to replace the pump once the pan is off.

Here's hoping you see the blade on the end of the distributor shaft
gone/mangled (but spin the pump anyway).

On Tue, 23 Aug 2005 00:05:34 UTC "Earle Horton"
<nurse--NOSPAM--busters@msn.com> wrote:

> As Bill says, the drive mechanism can break. I have also seen the oil
> pickup break off and fall into the sump. If you stopped when there was only
> ticking from the top end, there is the possibility that you saved it.
>
> This could have been a plain old defective part, and there may be no TSB.
> My advice is pull the pan, pull the pump, and try to figure out what
> happened.
>
> Earle
>
> "matt borland" <mborland@columbus.rr.com> wrote in message
> news:xHsOe.20140$2Q3.15820@tornado.ohiordc.rr.com. ..
> > The Jeep: 48000mi 2001 Cherokee Sport, 4.0L Auto.
> >
> > The Incident: Driving along, suddenly there's engine light,
> > followed by check guages light, accompanied by ticking
> > from top end and no oil pressure reading on the guage.
> >
> > I shut it off and cruise to a good pull-off spot. Pop the hood,
> > check the oil, plenty there and not too bad looking either.
> >
> >
> > The Most Obvious Diagnosis: Oil Pump Died.
> >
> >
> > Anybody here experienced this or heard about it? It just
> > seems odd that the usually indestructible 4.0L in one of
> > it's latest and finest forms would take a dump this early
> > in it's service life. I've had others that are still running around
> > at 160k+, hence I bought another one with low miles with
> > the intention of driving it for a long time.
> >
> >
> > I'm headed to the alldata site to see if there's a TSB...
> >
> >
> >
> > -Matt-
> >
> >
>
>


--
Will Honea

 

Could it be a blocked oil filter or oil pump pickup screen?
Are you using Fram filters???
Let us know what you find!
later,
dave AKA vwdoc1

"matt borland" <mborland@columbus.rr.com> wrote in message
news:xHsOe.20140$2Q3.15820@tornado.ohiordc.rr.com. ..
> The Jeep: 48000mi 2001 Cherokee Sport, 4.0L Auto.
>
> The Incident: Driving along, suddenly there's engine light,
> followed by check guages light, accompanied by ticking
> from top end and no oil pressure reading on the guage.
>
> I shut it off and cruise to a good pull-off spot. Pop the hood,
> check the oil, plenty there and not too bad looking either.
>
>
> The Most Obvious Diagnosis: Oil Pump Died.
>
>
> Anybody here experienced this or heard about it? It just
> seems odd that the usually indestructible 4.0L in one of
> it's latest and finest forms would take a dump this early
> in it's service life. I've had others that are still running around
> at 160k+, hence I bought another one with low miles with
> the intention of driving it for a long time.

 

Could it be a blocked oil filter or oil pump pickup screen?
Are you using Fram filters???
Let us know what you find!
later,
dave AKA vwdoc1

"matt borland" <mborland@columbus.rr.com> wrote in message
news:xHsOe.20140$2Q3.15820@tornado.ohiordc.rr.com. ..
> The Jeep: 48000mi 2001 Cherokee Sport, 4.0L Auto.
>
> The Incident: Driving along, suddenly there's engine light,
> followed by check guages light, accompanied by ticking
> from top end and no oil pressure reading on the guage.
>
> I shut it off and cruise to a good pull-off spot. Pop the hood,
> check the oil, plenty there and not too bad looking either.
>
>
> The Most Obvious Diagnosis: Oil Pump Died.
>
>
> Anybody here experienced this or heard about it? It just
> seems odd that the usually indestructible 4.0L in one of
> it's latest and finest forms would take a dump this early
> in it's service life. I've had others that are still running around
> at 160k+, hence I bought another one with low miles with
> the intention of driving it for a long time.

 

Could it be a blocked oil filter or oil pump pickup screen?
Are you using Fram filters???
Let us know what you find!
later,
dave AKA vwdoc1

"matt borland" <mborland@columbus.rr.com> wrote in message
news:xHsOe.20140$2Q3.15820@tornado.ohiordc.rr.com. ..
> The Jeep: 48000mi 2001 Cherokee Sport, 4.0L Auto.
>
> The Incident: Driving along, suddenly there's engine light,
> followed by check guages light, accompanied by ticking
> from top end and no oil pressure reading on the guage.
>
> I shut it off and cruise to a good pull-off spot. Pop the hood,
> check the oil, plenty there and not too bad looking either.
>
>
> The Most Obvious Diagnosis: Oil Pump Died.
>
>
> Anybody here experienced this or heard about it? It just
> seems odd that the usually indestructible 4.0L in one of
> it's latest and finest forms would take a dump this early
> in it's service life. I've had others that are still running around
> at 160k+, hence I bought another one with low miles with
> the intention of driving it for a long time.

 

Could it be a blocked oil filter or oil pump pickup screen?
Are you using Fram filters???
Let us know what you find!
later,
dave AKA vwdoc1

"matt borland" <mborland@columbus.rr.com> wrote in message
news:xHsOe.20140$2Q3.15820@tornado.ohiordc.rr.com. ..
> The Jeep: 48000mi 2001 Cherokee Sport, 4.0L Auto.
>
> The Incident: Driving along, suddenly there's engine light,
> followed by check guages light, accompanied by ticking
> from top end and no oil pressure reading on the guage.
>
> I shut it off and cruise to a good pull-off spot. Pop the hood,
> check the oil, plenty there and not too bad looking either.
>
>
> The Most Obvious Diagnosis: Oil Pump Died.
>
>
> Anybody here experienced this or heard about it? It just
> seems odd that the usually indestructible 4.0L in one of
> it's latest and finest forms would take a dump this early
> in it's service life. I've had others that are still running around
> at 160k+, hence I bought another one with low miles with
> the intention of driving it for a long time.

 

"One out of many daves" <PLEASEvwdoc1@NOSPAMhotmail.com> wrote in message
news:rWFOe.802$u_6.295@newssvr17.news.prodigy.com. ..
> Could it be a blocked oil filter or oil pump pickup screen?
> Are you using Fram filters???
> Let us know what you find!
> later,
> dave AKA vwdoc1


Thanks to everyone who replied.


Mystery solved! The cam position sensor sheared the
drive gear (as Bill suggested) and jammed up the works.


Everything else is fine since I got it shut down so quick.


I'd have shut it down immediately if it hadn't taken 20
seconds or so to convince myself that my 48000 mile
Jeep was indeed showing no oil pressure and ticking.


As for the oil change questions I use Napa filters and
this trip I tried the Mobil 5000 mile stuff. The oil has
about 3200 miles on it and while it does look pretty
clean it still smells gassy and looks a little thin so I'll
be changing it sooner rather than later. I bought it
because it was on sale and Mobil is usually good
oil, but I won't be extending my change interval using
this stuff... A true synthetic, sure I'll go 5000 miles
on a change but not this...


Thanks again for the input.


-Matt-

 

"One out of many daves" <PLEASEvwdoc1@NOSPAMhotmail.com> wrote in message
news:rWFOe.802$u_6.295@newssvr17.news.prodigy.com. ..
> Could it be a blocked oil filter or oil pump pickup screen?
> Are you using Fram filters???
> Let us know what you find!
> later,
> dave AKA vwdoc1


Thanks to everyone who replied.


Mystery solved! The cam position sensor sheared the
drive gear (as Bill suggested) and jammed up the works.


Everything else is fine since I got it shut down so quick.


I'd have shut it down immediately if it hadn't taken 20
seconds or so to convince myself that my 48000 mile
Jeep was indeed showing no oil pressure and ticking.


As for the oil change questions I use Napa filters and
this trip I tried the Mobil 5000 mile stuff. The oil has
about 3200 miles on it and while it does look pretty
clean it still smells gassy and looks a little thin so I'll
be changing it sooner rather than later. I bought it
because it was on sale and Mobil is usually good
oil, but I won't be extending my change interval using
this stuff... A true synthetic, sure I'll go 5000 miles
on a change but not this...


Thanks again for the input.


-Matt-

 

"One out of many daves" <PLEASEvwdoc1@NOSPAMhotmail.com> wrote in message
news:rWFOe.802$u_6.295@newssvr17.news.prodigy.com. ..
> Could it be a blocked oil filter or oil pump pickup screen?
> Are you using Fram filters???
> Let us know what you find!
> later,
> dave AKA vwdoc1


Thanks to everyone who replied.


Mystery solved! The cam position sensor sheared the
drive gear (as Bill suggested) and jammed up the works.


Everything else is fine since I got it shut down so quick.


I'd have shut it down immediately if it hadn't taken 20
seconds or so to convince myself that my 48000 mile
Jeep was indeed showing no oil pressure and ticking.


As for the oil change questions I use Napa filters and
this trip I tried the Mobil 5000 mile stuff. The oil has
about 3200 miles on it and while it does look pretty
clean it still smells gassy and looks a little thin so I'll
be changing it sooner rather than later. I bought it
because it was on sale and Mobil is usually good
oil, but I won't be extending my change interval using
this stuff... A true synthetic, sure I'll go 5000 miles
on a change but not this...


Thanks again for the input.


-Matt-

 

"One out of many daves" <PLEASEvwdoc1@NOSPAMhotmail.com> wrote in message
news:rWFOe.802$u_6.295@newssvr17.news.prodigy.com. ..
> Could it be a blocked oil filter or oil pump pickup screen?
> Are you using Fram filters???
> Let us know what you find!
> later,
> dave AKA vwdoc1


Thanks to everyone who replied.


Mystery solved! The cam position sensor sheared the
drive gear (as Bill suggested) and jammed up the works.


Everything else is fine since I got it shut down so quick.


I'd have shut it down immediately if it hadn't taken 20
seconds or so to convince myself that my 48000 mile
Jeep was indeed showing no oil pressure and ticking.


As for the oil change questions I use Napa filters and
this trip I tried the Mobil 5000 mile stuff. The oil has
about 3200 miles on it and while it does look pretty
clean it still smells gassy and looks a little thin so I'll
be changing it sooner rather than later. I bought it
because it was on sale and Mobil is usually good
oil, but I won't be extending my change interval using
this stuff... A true synthetic, sure I'll go 5000 miles
on a change but not this...


Thanks again for the input.


-Matt-