2000 Jeep Grand Cherokee 4.7 Engine stalling

I have a 2000 Jeep Grand Cherokee, 4.7 liter engine. 205,000 miles.
Engine has been literally perfect until last six months or so.

In the last week, engine has stalled three times, at very slow idle, or very
low speed. I have NO problems starting the engine. Today, while
traveling
on the interstate at 70 mph, my engine shuts off entirely, and all of my
gauges
go down to zero. It was as though some one unhooked the battery and the
alternator at the same time. I allowed the car to slow down to about 50
mph
and all of a sudden, the gauges snap back into "normal" positions, and the
engine resumes
normal running, and I drive 300 more miles home without mishap, except that
it again stalled twice at very low idle speeds (at red lights).

Other than these rather serious quirks, I have good engine performance. No
noises, etc.
I am not a mechanic, but I would have suspected a fuel delivery problem
were it not for
the fact that my gauges went dead, which makes me wonder about the computer
module
or something like that. I have done the ignition switch on and off three
times in sequence, but I get no error code. Just reads "done" after the
third switch. I hope to get an OBD done asap.


Within past six months I had some slow idle stalling and slow cranking
problems. Based
on advice here, I had the throttle body cleaned and the iac cleaned out.
That took care of those
problems at the time. Again, no problems starting now, just slow idle
stalling, and the very weird engine and gauge shutdown at 70 mph (occurred
once).


Any commnents or advice will be appreciated. What should I be checking ?

James

Sorry, I forgot to leave out what could be an important fact....

When the shutdown occurred at high speed, and then the engine restarted on
its own, a special light came on the dash that I don't recall ever noticing
before. I looked it up in my manual, and it was for the keyless sentry
system of the Jeep. Hmmmm..... could a malfunction of this key cause a
complete electrical and engine shutdown ??

Could I have two very different things going on at the same time ? The high
speed shutdown caused by one problem, and the slow idle stall caused by
another ??

James

James wrote:
> I have a 2000 Jeep Grand Cherokee, 4.7 liter engine. 205,000 miles.

> In the last week, engine has stalled three times, at very slow idle,
> or very low speed. I have NO problems starting the engine. Today,

> Within past six months I had some slow idle stalling and slow cranking
> problems.

> Any commnents or advice will be appreciated. What should I be
> checking ?

First wiggle the battery terminals to make sure they aren't loose
or broken.

High on my list as next culprit is the CPS (Crankshaft Position Sensor)
although a failing coil, coil rail, or coil on plug (depends on your
system) will also cause these issues without setting codes.

At higher RPM a failed spark will generally not be noticable. I had a
run-in with a bad coil in my 93.

Fuel delivery will show up as a power sag or ping at wide open throttle.

--
DougW

James wrote:
> Sorry, I forgot to leave out what could be an important fact....
>
> When the shutdown occurred at high speed, and then the engine
> restarted on its own, a special light came on the dash that I don't
> recall ever noticing before. I looked it up in my manual, and it was
> for the keyless sentry system of the Jeep. Hmmmm..... could a
> malfunction of this key cause a complete electrical and engine
> shutdown ??

Failed SKIM won't shut the engine down once it has started. I think
it's a restart gremlin. Starting to point towards a bad connection
at the battery or a bad engine ground.

> Could I have two very different things going on at the same time ?
> The high speed shutdown caused by one problem, and the slow idle
> stall caused by another ??

You can. But usually one problem tends to cause others.
Oddly though the battery issue usually sets all sorts of codes.

This is starting to sound like a CPS issue.

--
DougW

Doug, you think a bad CPS could cause a total electrical and engine failure
at high speed / 70 mph ????

I had thought that the CPS problem only related to starting issues........
but I am not a mechanic.


James

James wrote:
> Doug, you think a bad CPS could cause a total electrical and engine
> failure at high speed / 70 mph ????

It can. The CPS is used to tell the computer when the engine gets to TDC
so it can set timing. Loose that signal and the engine will shut down to
prevent misfire.

> I had thought that the CPS problem only related to starting
> issues........ but I am not a mechanic.

CPS usually gives grief at low speeds causing a stall as the vehicle
comes to a stop. But it's been known to fail at other times.

Check the plug. CPS is on the transmission 11:00 position and usually
routs up the passenger side of the engine to the harness.

--
DougW

Thank you so much Doug !!

James

James wrote:
> Thank you so much Doug !!
>
> James

no problem.. hope the info helps.

It's nice to actually see somethign other
than the usual noise in this group.

--
DougW

In article > ,
"James" > wrote:

> Sorry, I forgot to leave out what could be an important fact....
>
> When the shutdown occurred at high speed, and then the engine restarted on
> its own, a special light came on the dash that I don't recall ever noticing
> before. I looked it up in my manual, and it was for the keyless sentry
> system of the Jeep. Hmmmm..... could a malfunction of this key cause a
> complete electrical and engine shutdown ??
>
> Could I have two very different things going on at the same time ? The high
> speed shutdown caused by one problem, and the slow idle stall caused by
> another ??
>
> James

Just shoot it, and bury it under your roses. At least your roses will be
getting some iron, while you are listening Rush on your AM squawk radio.
--
- Billy
"Fascism should more properly be called corporatism because it is the
merger of state and corporate power." - Benito Mussolini.
http://www.youtube.com/watch?v=Arn3lF5XSUg
http://www.thirdworldtraveler.com/Zinn/HZinn_page.html

On Wed, 2 Jun 2010 21:30:50 -0500, "James" <no >
wrote:

>Since I first posted this problem, I installed the CPS , about a month ago.
>So, for a full month, I have had NO problem. But today, at slow speeds of
>20-30 mph, the engine shut down completely. Then, the starter would turn
>over and over, but the engine would not crank. All gauges remained at
>zero.

Sounds like an ignition switch problem...

>After some time, and turning the ignition on and off, the gauges went back
>to
>normal, and the engine started right up. I am not a mechanic, but it seems
>to
>me that this HAS to be an electrical problem.

Probably, given the gauge problems...

>
>Yes, I will have a mechanic do the ODC codes asap, but what kind of things
>are left, that I should be looking for ??
>

Check the connections/plugs to the PCM.