Wrangler starts, runs for 3 seconds?

Hi Bill,
Pull the codes: http://www.wjjeeps.com/faultcodes.htm
God Bless America, ßill O|||||||O
http://www.billhughes.com/

ElAlumbrado wrote:
>
> I've got a 2000 4-cylinder manual Wrangler. The other day, after
> stopping for a bit in the back-country of Big Bend National Park, we
> started experiencing a problem. The Jeep would start and run normally
> for roughly 3 seconds, then quit as if the ignition were turned off. I
> checked everything I could at the time, including fuses, relays, fuel
> delivery, and airflow. Fuel was near full and oil pressure read normal
> before the engine cut off. Problem is reliably repeatable (meaning I
> still can't get the blasted thing to run for more than 3 seconds).
> Couldn't find anything obviously wrong, which makes me suspect it's an
> "electronic" problem. Does anybody have any ideas what to look for?
>
> After waiting for about 8 hours, the Border Patrol finally found us and
> dispatched a *very* expensive tow truck to haul us back to our RV. With
> the Jeep malfunctioning, we cut our little vacation short, hooked it up
> to the RV and drove home. I'm reluctant to take the Jeep off-road again
> until (1) I know what caused the problem and (2) have a way to fix it
> (at least temporarily) in the field should it happen again.
>
> Thanks for your help,
> Bill
>
>

It won't even start without a good CPS signal which is the engine's
Master timing signal that provides timing for everything. Without the
CPS, it has no idea even when to send spark to the spark plugs. Yes the
PDC shuts the ASD relay down in 3 seconds if any of lots of signals are
not there but the engine won't even start without a good CPS timing signal.

L.W.(ßill) Hughes III wrote:
> Could be, if the Auto Shutdown relay doesn't get a signal from the
> Crank Position Sensor it will shut down at three seconds, as per:
> http://www.billhughes.com/TJshutdown.pdf
> God Bless America, ßill O|||||||O
>
>
> ISellJeeps wrote:
>
>>try the crank position sensor

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.cox.net/jerrypb/

Jerry, the link Bill gives says if the PCM does not receive a signal
from the CPS within 3 seconds of cranking it will shut down the
injectors.

That does imply the engine will start fine and then up and quit.

It sure wouldn't hurt to give the CPS plug and socket a quick clean with
a contact cleaner spray.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Jerry Bransford wrote:
>
> It won't even start without a good CPS signal which is the engine's
> Master timing signal that provides timing for everything. Without the
> CPS, it has no idea even when to send spark to the spark plugs. Yes the
> PDC shuts the ASD relay down in 3 seconds if any of lots of signals are
> not there but the engine won't even start without a good CPS timing signal.
>
> L.W.(ßill) Hughes III wrote:
> > Could be, if the Auto Shutdown relay doesn't get a signal from the
> > Crank Position Sensor it will shut down at three seconds, as per:
> > http://www.billhughes.com/TJshutdown.pdf
> > God Bless America, ßill O|||||||O
> >
> >
> > ISellJeeps wrote:
> >
> >>try the crank position sensor
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.cox.net/jerrypb/

Yes of course Mike but the engine will not actually start without the
CPS signal. If the CPS signal is not present, it will not start and
then within 3 seconds the ASD will shut the fuel flow off to the injectors.

Mike Romain wrote:
> Jerry, the link Bill gives says if the PCM does not receive a signal
> from the CPS within 3 seconds of cranking it will shut down the
> injectors.
>
> That does imply the engine will start fine and then up and quit.
>
> It sure wouldn't hurt to give the CPS plug and socket a quick clean with
> a contact cleaner spray.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> Jerry Bransford wrote:
>
>>It won't even start without a good CPS signal which is the engine's
>>Master timing signal that provides timing for everything. Without the
>>CPS, it has no idea even when to send spark to the spark plugs. Yes the
>>PDC shuts the ASD relay down in 3 seconds if any of lots of signals are
>>not there but the engine won't even start without a good CPS timing signal.
>>
>>L.W.(ßill) Hughes III wrote:
>>
>>> Could be, if the Auto Shutdown relay doesn't get a signal from the
>>>Crank Position Sensor it will shut down at three seconds, as per:
>>>http://www.billhughes.com/TJshutdown.pdf
>>> God Bless America, ßill O|||||||O

>>>
>>>ISellJeeps wrote:
>>>
>>>
>>>>try the crank position sensor
>>
>>--
>>Jerry Bransford
>>PP-ASEL N6TAY
>>See the Geezer Jeep at
>>http://members.cox.net/jerrypb/

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.cox.net/jerrypb/

I just read it again carefully and it says it only 'looks' for the CPS
signal on starter turning. If it doesn't get it after 3 seconds it
shuts off the fuel.

I would think the same as you do, but that document seems to imply
otherwise.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's

Jerry Bransford wrote:
>
> Yes of course Mike but the engine will not actually start without the
> CPS signal. If the CPS signal is not present, it will not start and
> then within 3 seconds the ASD will shut the fuel flow off to the injectors.
>
> Mike Romain wrote:
> > Jerry, the link Bill gives says if the PCM does not receive a signal
> > from the CPS within 3 seconds of cranking it will shut down the
> > injectors.
> >
> > That does imply the engine will start fine and then up and quit.
> >
> > It sure wouldn't hurt to give the CPS plug and socket a quick clean with
> > a contact cleaner spray.
> >
> > Mike
> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> > 88 Cherokee 235 BFG AT's
> >
> > Jerry Bransford wrote:
> >
> >>It won't even start without a good CPS signal which is the engine's
> >>Master timing signal that provides timing for everything. Without the
> >>CPS, it has no idea even when to send spark to the spark plugs. Yes the
> >>PDC shuts the ASD relay down in 3 seconds if any of lots of signals are
> >>not there but the engine won't even start without a good CPS timing signal.
> >>
> >>L.W.(ßill) Hughes III wrote:
> >>
> >>> Could be, if the Auto Shutdown relay doesn't get a signal from the
> >>>Crank Position Sensor it will shut down at three seconds, as per:
> >>>http://www.billhughes.com/TJshutdown.pdf
> >>> God Bless America, ßill O|||||||O
>
> >>>
> >>>ISellJeeps wrote:
> >>>
> >>>
> >>>>try the crank position sensor
> >>
> >>--
> >>Jerry Bransford
> >>PP-ASEL N6TAY
> >>See the Geezer Jeep at
> >>http://members.cox.net/jerrypb/
>
> --
> Jerry Bransford
> PP-ASEL N6TAY
> See the Geezer Jeep at
> http://members.cox.net/jerrypb/

I see where you're coming from Mike but without that timing signal, the
engine cannot start since no spark can/will be generated.

Jerry

Mike Romain wrote:
> I just read it again carefully and it says it only 'looks' for the CPS
> signal on starter turning. If it doesn't get it after 3 seconds it
> shuts off the fuel.
>
> I would think the same as you do, but that document seems to imply
> otherwise.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's
>
> Jerry Bransford wrote:
>
>>Yes of course Mike but the engine will not actually start without the
>>CPS signal. If the CPS signal is not present, it will not start and
>>then within 3 seconds the ASD will shut the fuel flow off to the injectors.
>>
>>Mike Romain wrote:
>>
>>>Jerry, the link Bill gives says if the PCM does not receive a signal
>>>from the CPS within 3 seconds of cranking it will shut down the
>>>injectors.
>>>
>>>That does imply the engine will start fine and then up and quit.
>>>
>>>It sure wouldn't hurt to give the CPS plug and socket a quick clean with
>>>a contact cleaner spray.
>>>
>>>Mike
>>>86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>>>88 Cherokee 235 BFG AT's
>>>
>>>Jerry Bransford wrote:
>>>
>>>
>>>>It won't even start without a good CPS signal which is the engine's
>>>>Master timing signal that provides timing for everything. Without the
>>>>CPS, it has no idea even when to send spark to the spark plugs. Yes the
>>>>PDC shuts the ASD relay down in 3 seconds if any of lots of signals are
>>>>not there but the engine won't even start without a good CPS timing signal.
>>>>
>>>>L.W.(ßill) Hughes III wrote:
>>>>
>>>>
>>>>> Could be, if the Auto Shutdown relay doesn't get a signal from the
>>>>>Crank Position Sensor it will shut down at three seconds, as per:
>>>>>http://www.billhughes.com/TJshutdown.pdf
>>>>> God Bless America, ßill O|||||||O

>>>>>
>>>>>ISellJeeps wrote:
>>>>>
>>>>>
>>>>>
>>>>>>try the crank position sensor
>>>>
>>>>--
>>>>Jerry Bransford
>>>>PP-ASEL N6TAY
>>>>See the Geezer Jeep at
>>>>http://members.cox.net/jerrypb/
>>
>>--
>>Jerry Bransford
>>PP-ASEL N6TAY
>>See the Geezer Jeep at
>>http://members.cox.net/jerrypb/

--
Jerry Bransford
PP-ASEL N6TAY
See the Geezer Jeep at
http://members.cox.net/jerrypb/

Hi Mike,
I can tell you there are varying degrees of Crank Position Sensor
failure that have happened to every one of my Brother's Cherokees,
except for the last WJ, one of the failures threw the computer into a
safe mode with a top speed of twenty miles an hour.
God Bless America, ßill O|||||||O
http://www.billhughes.com/

Mike Romain wrote:
>
> I just read it again carefully and it says it only 'looks' for the CPS
> signal on starter turning. If it doesn't get it after 3 seconds it
> shuts off the fuel.
>
> I would think the same as you do, but that document seems to imply
> otherwise.
>
> Mike
> 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> 88 Cherokee 235 BFG AT's

either the skim key or skim module is falling need to pull fault codes

ElAlumbrado wrote:

> "Jerry Bransford" > wrote in message
> news:Gk4_d.72020$Tt.69316@fed1read05...
> > Do you have a security "Sentry" key system? If so, I'm betting it's
> > related to that.
>
> Key is the same key I've been using for 5 years. Perhaps a sensor
> failure of some kind?
>
> Bill