I have a '97 Grand Cherokee 4x4 that has had a myriad of ignition problems
(well ... maybe one problem with a myriad of 'solutions'). I finally
replaced the computer and the problems stopped for a couple of months. This
week the engine died a couple of times while driving in hot weather and then
would start again after a few minutes. It then began not starting when
driven and then parked for about a half hour. It finally would not start
again. No codes, no engine light. Towed to mechanic.

He says the fuel pump and the fuel pump relay are bad. It was replaced last
year. The mechanic says the relay may have burnt out the fuel pump over time
by creating spikes and low voltage. I don't know much about the system, but
that sounds very strange for relays. Is this a likely diagnosis?

Thanks,

Joe M

 

I can tell you my fuel pump took out it's relay, it wouldn't stop
running the pump with the ignition off. It ran another couple of months with
a new relay and replaced culprit clogged filter. As a test it should run for
a couple of seconds every time you turn on the ignition key on then shut
off, if the engine is not started. But this really sounds like the
Crankshaft Position Sensor:
http://jeep.off-road.com/jeep/articl....jsp?id=257990 That's why
I asked you to test for the sound of fuel to confirm it's really not
running.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/


"Joe_M" <x24w0cg02@NOsneakSPAMemail.com> wrote in message
news:EvWki.5849$rR.1016@newsread2.news.pas.earthli nk.net...
> I have a '97 Grand Cherokee 4x4 that has had a myriad of ignition problems
> (well ... maybe one problem with a myriad of 'solutions'). I finally
> replaced the computer and the problems stopped for a couple of months.
This
> week the engine died a couple of times while driving in hot weather and
then
> would start again after a few minutes. It then began not starting when
> driven and then parked for about a half hour. It finally would not start
> again. No codes, no engine light. Towed to mechanic.
>
> He says the fuel pump and the fuel pump relay are bad. It was replaced
last
> year. The mechanic says the relay may have burnt out the fuel pump over
time
> by creating spikes and low voltage. I don't know much about the system,
but
> that sounds very strange for relays. Is this a likely diagnosis?
>
> Thanks,
>
> Joe M
>
>



--
Posted via a free Usenet account from http://www.teranews.com

 

I can tell you my fuel pump took out it's relay, it wouldn't stop
running the pump with the ignition off. It ran another couple of months with
a new relay and replaced culprit clogged filter. As a test it should run for
a couple of seconds every time you turn on the ignition key on then shut
off, if the engine is not started. But this really sounds like the
Crankshaft Position Sensor:
http://jeep.off-road.com/jeep/articl....jsp?id=257990 That's why
I asked you to test for the sound of fuel to confirm it's really not
running.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/


"Joe_M" <x24w0cg02@NOsneakSPAMemail.com> wrote in message
news:EvWki.5849$rR.1016@newsread2.news.pas.earthli nk.net...
> I have a '97 Grand Cherokee 4x4 that has had a myriad of ignition problems
> (well ... maybe one problem with a myriad of 'solutions'). I finally
> replaced the computer and the problems stopped for a couple of months.
This
> week the engine died a couple of times while driving in hot weather and
then
> would start again after a few minutes. It then began not starting when
> driven and then parked for about a half hour. It finally would not start
> again. No codes, no engine light. Towed to mechanic.
>
> He says the fuel pump and the fuel pump relay are bad. It was replaced
last
> year. The mechanic says the relay may have burnt out the fuel pump over
time
> by creating spikes and low voltage. I don't know much about the system,
but
> that sounds very strange for relays. Is this a likely diagnosis?
>
> Thanks,
>
> Joe M
>
>



--
Posted via a free Usenet account from http://www.teranews.com

 

I can tell you my fuel pump took out it's relay, it wouldn't stop
running the pump with the ignition off. It ran another couple of months with
a new relay and replaced culprit clogged filter. As a test it should run for
a couple of seconds every time you turn on the ignition key on then shut
off, if the engine is not started. But this really sounds like the
Crankshaft Position Sensor:
http://jeep.off-road.com/jeep/articl....jsp?id=257990 That's why
I asked you to test for the sound of fuel to confirm it's really not
running.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/


"Joe_M" <x24w0cg02@NOsneakSPAMemail.com> wrote in message
news:EvWki.5849$rR.1016@newsread2.news.pas.earthli nk.net...
> I have a '97 Grand Cherokee 4x4 that has had a myriad of ignition problems
> (well ... maybe one problem with a myriad of 'solutions'). I finally
> replaced the computer and the problems stopped for a couple of months.
This
> week the engine died a couple of times while driving in hot weather and
then
> would start again after a few minutes. It then began not starting when
> driven and then parked for about a half hour. It finally would not start
> again. No codes, no engine light. Towed to mechanic.
>
> He says the fuel pump and the fuel pump relay are bad. It was replaced
last
> year. The mechanic says the relay may have burnt out the fuel pump over
time
> by creating spikes and low voltage. I don't know much about the system,
but
> that sounds very strange for relays. Is this a likely diagnosis?
>
> Thanks,
>
> Joe M
>
>



--
Posted via a free Usenet account from http://www.teranews.com

 

I can tell you my fuel pump took out it's relay, it wouldn't stop
running the pump with the ignition off. It ran another couple of months with
a new relay and replaced culprit clogged filter. As a test it should run for
a couple of seconds every time you turn on the ignition key on then shut
off, if the engine is not started. But this really sounds like the
Crankshaft Position Sensor:
http://jeep.off-road.com/jeep/articl....jsp?id=257990 That's why
I asked you to test for the sound of fuel to confirm it's really not
running.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/


"Joe_M" <x24w0cg02@NOsneakSPAMemail.com> wrote in message
news:EvWki.5849$rR.1016@newsread2.news.pas.earthli nk.net...
> I have a '97 Grand Cherokee 4x4 that has had a myriad of ignition problems
> (well ... maybe one problem with a myriad of 'solutions'). I finally
> replaced the computer and the problems stopped for a couple of months.
This
> week the engine died a couple of times while driving in hot weather and
then
> would start again after a few minutes. It then began not starting when
> driven and then parked for about a half hour. It finally would not start
> again. No codes, no engine light. Towed to mechanic.
>
> He says the fuel pump and the fuel pump relay are bad. It was replaced
last
> year. The mechanic says the relay may have burnt out the fuel pump over
time
> by creating spikes and low voltage. I don't know much about the system,
but
> that sounds very strange for relays. Is this a likely diagnosis?
>
> Thanks,
>
> Joe M
>
>



--
Posted via a free Usenet account from http://www.teranews.com

 

Joe_M wrote:
> I have a '97 Grand Cherokee 4x4 that has had a myriad of ignition problems
> (well ... maybe one problem with a myriad of 'solutions'). I finally
> replaced the computer and the problems stopped for a couple of months. This
> week the engine died a couple of times while driving in hot weather and then
> would start again after a few minutes. It then began not starting when
> driven and then parked for about a half hour. It finally would not start
> again. No codes, no engine light. Towed to mechanic.
>
> He says the fuel pump and the fuel pump relay are bad. It was replaced last
> year. The mechanic says the relay may have burnt out the fuel pump over time
> by creating spikes and low voltage. I don't know much about the system, but
> that sounds very strange for relays. Is this a likely diagnosis?
>
> Thanks,
>
> Joe M
>
>
You are still describing a code 12 issue I think.....

I would be making 'really' sure the body of the vehicle had full power.

To do this, I take a multimeter and read the volts at the battery posts
with the engine running and the headlights and heater fan and wipers on.
I then move the negative meter probe to the body with the positive
still on the battery positive and compare the voltages.

If the voltages are different, your body ground path is bad.

Good luck!

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

 

Joe_M wrote:
> I have a '97 Grand Cherokee 4x4 that has had a myriad of ignition problems
> (well ... maybe one problem with a myriad of 'solutions'). I finally
> replaced the computer and the problems stopped for a couple of months. This
> week the engine died a couple of times while driving in hot weather and then
> would start again after a few minutes. It then began not starting when
> driven and then parked for about a half hour. It finally would not start
> again. No codes, no engine light. Towed to mechanic.
>
> He says the fuel pump and the fuel pump relay are bad. It was replaced last
> year. The mechanic says the relay may have burnt out the fuel pump over time
> by creating spikes and low voltage. I don't know much about the system, but
> that sounds very strange for relays. Is this a likely diagnosis?
>
> Thanks,
>
> Joe M
>
>
You are still describing a code 12 issue I think.....

I would be making 'really' sure the body of the vehicle had full power.

To do this, I take a multimeter and read the volts at the battery posts
with the engine running and the headlights and heater fan and wipers on.
I then move the negative meter probe to the body with the positive
still on the battery positive and compare the voltages.

If the voltages are different, your body ground path is bad.

Good luck!

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

 

Joe_M wrote:
> I have a '97 Grand Cherokee 4x4 that has had a myriad of ignition problems
> (well ... maybe one problem with a myriad of 'solutions'). I finally
> replaced the computer and the problems stopped for a couple of months. This
> week the engine died a couple of times while driving in hot weather and then
> would start again after a few minutes. It then began not starting when
> driven and then parked for about a half hour. It finally would not start
> again. No codes, no engine light. Towed to mechanic.
>
> He says the fuel pump and the fuel pump relay are bad. It was replaced last
> year. The mechanic says the relay may have burnt out the fuel pump over time
> by creating spikes and low voltage. I don't know much about the system, but
> that sounds very strange for relays. Is this a likely diagnosis?
>
> Thanks,
>
> Joe M
>
>
You are still describing a code 12 issue I think.....

I would be making 'really' sure the body of the vehicle had full power.

To do this, I take a multimeter and read the volts at the battery posts
with the engine running and the headlights and heater fan and wipers on.
I then move the negative meter probe to the body with the positive
still on the battery positive and compare the voltages.

If the voltages are different, your body ground path is bad.

Good luck!

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

 

Joe_M wrote:
> I have a '97 Grand Cherokee 4x4 that has had a myriad of ignition problems
> (well ... maybe one problem with a myriad of 'solutions'). I finally
> replaced the computer and the problems stopped for a couple of months. This
> week the engine died a couple of times while driving in hot weather and then
> would start again after a few minutes. It then began not starting when
> driven and then parked for about a half hour. It finally would not start
> again. No codes, no engine light. Towed to mechanic.
>
> He says the fuel pump and the fuel pump relay are bad. It was replaced last
> year. The mechanic says the relay may have burnt out the fuel pump over time
> by creating spikes and low voltage. I don't know much about the system, but
> that sounds very strange for relays. Is this a likely diagnosis?
>
> Thanks,
>
> Joe M
>
>
You are still describing a code 12 issue I think.....

I would be making 'really' sure the body of the vehicle had full power.

To do this, I take a multimeter and read the volts at the battery posts
with the engine running and the headlights and heater fan and wipers on.
I then move the negative meter probe to the body with the positive
still on the battery positive and compare the voltages.

If the voltages are different, your body ground path is bad.

Good luck!

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's - Gone to the rust pile...
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

 

Thanks Bill,

Already replaced the crank position sensor when previously chasing P0351
codes. Did not seem to have any impact, but I hear it often accounts for
strange problems.

"L.W. (Bill) ------ III" <LWBill------@------.net> wrote in message
news:46944946$0$16366$88260bb3@free.teranews.com.. .
> I can tell you my fuel pump took out it's relay, it wouldn't stop
> running the pump with the ignition off. It ran another couple of months
> with
> a new relay and replaced culprit clogged filter. As a test it should run
> for
> a couple of seconds every time you turn on the ignition key on then shut
> off, if the engine is not started. But this really sounds like the
> Crankshaft Position Sensor:
> http://jeep.off-road.com/jeep/articl....jsp?id=257990 That's
> why
> I asked you to test for the sound of fuel to confirm it's really not
> running.
> God Bless America, Bill O|||||||O
> mailto:-------------------- http://www.----------.com/
>