'Something' is shutting down the fuel pump. Alarms can have that
feature....

You should for sure see a voltage spike at the rear junction when the
key hits run.

I would next check right at the relay. I would look for the trigger
signal when the key hits run. If I have that, then I would be thinking
the contact in the relay box might be bad.

Could you have a bad ignition switch?

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

Casper wrote:
>
> Already swapped Fuel/ABS and Start/AutoShutdown (All four) relays.
> Problem perisists.
> Tested rear junction with OHM meter while turning ignition to RUN
> position and no voltage.

 

'Something' is shutting down the fuel pump. Alarms can have that
feature....

You should for sure see a voltage spike at the rear junction when the
key hits run.

I would next check right at the relay. I would look for the trigger
signal when the key hits run. If I have that, then I would be thinking
the contact in the relay box might be bad.

Could you have a bad ignition switch?

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

Casper wrote:
>
> Already swapped Fuel/ABS and Start/AutoShutdown (All four) relays.
> Problem perisists.
> Tested rear junction with OHM meter while turning ignition to RUN
> position and no voltage.

 

'Something' is shutting down the fuel pump. Alarms can have that
feature....

You should for sure see a voltage spike at the rear junction when the
key hits run.

I would next check right at the relay. I would look for the trigger
signal when the key hits run. If I have that, then I would be thinking
the contact in the relay box might be bad.

Could you have a bad ignition switch?

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

Casper wrote:
>
> Already swapped Fuel/ABS and Start/AutoShutdown (All four) relays.
> Problem perisists.
> Tested rear junction with OHM meter while turning ignition to RUN
> position and no voltage.

 

Casper did pass the time by typing:
> Already swapped Fuel/ABS and Start/AutoShutdown (All four) relays.
> Problem perisists.
> Tested rear junction with OHM meter while turning ignition to RUN
> position and no voltage.

Let's go over the basics then.

From the front of the vehicle, remove the fuel pump relay
Looking into the hole:

7
|

6| -8- |10

-9-

With the ignition on, hole 7 should
have 12V from the power center fuses 3(20A) and 15(30A)
(same location as the relays)
Also check fuse2(20A), the ASD power fuse.

Hole 6 should also have 12V, if not check fuse 6(15A)

Hole 9 feeds the pump and the heated O2 sensor
(If you found blown fuses take a look at the O2 sensor
and follow the wire back along the engine to where a clip
holds it to the block, then follow that wire up to another
clip up above and forward of the engine mount. sometimes
that wire will melt and short out. That short can/will blow
fuses.)

If all looks good at this point then
Jumping pin 9 to pin 7 will turn the pump on.

You should be able to hear it or watch the fuel rail
pressure jump.

--
DougW

 

Casper did pass the time by typing:
> Already swapped Fuel/ABS and Start/AutoShutdown (All four) relays.
> Problem perisists.
> Tested rear junction with OHM meter while turning ignition to RUN
> position and no voltage.

Let's go over the basics then.

From the front of the vehicle, remove the fuel pump relay
Looking into the hole:

7
|

6| -8- |10

-9-

With the ignition on, hole 7 should
have 12V from the power center fuses 3(20A) and 15(30A)
(same location as the relays)
Also check fuse2(20A), the ASD power fuse.

Hole 6 should also have 12V, if not check fuse 6(15A)

Hole 9 feeds the pump and the heated O2 sensor
(If you found blown fuses take a look at the O2 sensor
and follow the wire back along the engine to where a clip
holds it to the block, then follow that wire up to another
clip up above and forward of the engine mount. sometimes
that wire will melt and short out. That short can/will blow
fuses.)

If all looks good at this point then
Jumping pin 9 to pin 7 will turn the pump on.

You should be able to hear it or watch the fuel rail
pressure jump.

--
DougW

 

Casper did pass the time by typing:
> Already swapped Fuel/ABS and Start/AutoShutdown (All four) relays.
> Problem perisists.
> Tested rear junction with OHM meter while turning ignition to RUN
> position and no voltage.

Let's go over the basics then.

From the front of the vehicle, remove the fuel pump relay
Looking into the hole:

7
|

6| -8- |10

-9-

With the ignition on, hole 7 should
have 12V from the power center fuses 3(20A) and 15(30A)
(same location as the relays)
Also check fuse2(20A), the ASD power fuse.

Hole 6 should also have 12V, if not check fuse 6(15A)

Hole 9 feeds the pump and the heated O2 sensor
(If you found blown fuses take a look at the O2 sensor
and follow the wire back along the engine to where a clip
holds it to the block, then follow that wire up to another
clip up above and forward of the engine mount. sometimes
that wire will melt and short out. That short can/will blow
fuses.)

If all looks good at this point then
Jumping pin 9 to pin 7 will turn the pump on.

You should be able to hear it or watch the fuel rail
pressure jump.

--
DougW

 

Casper did pass the time by typing:
> Already swapped Fuel/ABS and Start/AutoShutdown (All four) relays.
> Problem perisists.
> Tested rear junction with OHM meter while turning ignition to RUN
> position and no voltage.

Let's go over the basics then.

From the front of the vehicle, remove the fuel pump relay
Looking into the hole:

7
|

6| -8- |10

-9-

With the ignition on, hole 7 should
have 12V from the power center fuses 3(20A) and 15(30A)
(same location as the relays)
Also check fuse2(20A), the ASD power fuse.

Hole 6 should also have 12V, if not check fuse 6(15A)

Hole 9 feeds the pump and the heated O2 sensor
(If you found blown fuses take a look at the O2 sensor
and follow the wire back along the engine to where a clip
holds it to the block, then follow that wire up to another
clip up above and forward of the engine mount. sometimes
that wire will melt and short out. That short can/will blow
fuses.)

If all looks good at this point then
Jumping pin 9 to pin 7 will turn the pump on.

You should be able to hear it or watch the fuel rail
pressure jump.

--
DougW

 

Ok, here's the current situation...

Tested all the relays and engine compartment fuse/relay box and they
are all fine. Checked the interior fuse panel and all is fine.
Everything in these places is getting voltage.

Here is something we (my good neighbor and I) noticed during this
testing and starting attempts...

If you turn the ignition to the RUN position, four dash lights should
come on. 1) ABS, 2) Check Engine, 3)Airbag and 4) Seatbelt.

If you turn the key to RUN, and the "Check Engine" light comes on, the
jeep will start. If the "Check Engine" light does not come on, the
jeep will NOT start. If you put the key in the RUN position and the
"check engine" light does not come on, AND you leave the key in the
RUN position, eventually the "Check Engine" light comes on and the
jeep starts. Every time the "Check Engine" light comes on, you can
hear the fuel pump prime and start the jeep, usually on the first try.

We repeated this pattern for a good 30-60 minutes, giving different
time intervals inbetween because sometimes the dash lights all come on
as they should on the first trr, and we wanted to make sure it wasn't
initial luck. We confirmed there is a definite pattern.

On the very last attempt, it took longer for the light to come on.. at
least another 20 seconds than all the other previous attempts, AND
when the "Check Engine" light came on, so did the Security light. The
Security light remains on for about 3-5 seconds and then went off.

I know the system is running checks when the light is on, and
sometimes something isn't letting it come on, ergo no checks and
nofuel priming. Anyone ever see this before?

Last note.. sometimes, and only sometimes, I hear a clicking when I
turn the key to RUN. It sounds like a circuit switching on/off. During
all this testing, I did not hear it once.



>On Fri, 17 Feb 2006 16:54:11 -0600, "DougW" wrote:
>Let's go over the basics then.
>
>From the front of the vehicle, remove the fuel pump relay
>Looking into the hole:
>
> 7
> |
>
>6| -8- |10
>
> -9-
>
>With the ignition on, hole 7 should
>have 12V from the power center fuses 3(20A) and 15(30A)
>(same location as the relays)
>Also check fuse2(20A), the ASD power fuse.
>
>Hole 6 should also have 12V, if not check fuse 6(15A)
>
>Hole 9 feeds the pump and the heated O2 sensor
>(If you found blown fuses take a look at the O2 sensor
>and follow the wire back along the engine to where a clip
>holds it to the block, then follow that wire up to another
>clip up above and forward of the engine mount. sometimes
>that wire will melt and short out. That short can/will blow
>fuses.)
>
>If all looks good at this point then
>Jumping pin 9 to pin 7 will turn the pump on.
>
>You should be able to hear it or watch the fuel rail
>pressure jump.

 

Ok, here's the current situation...

Tested all the relays and engine compartment fuse/relay box and they
are all fine. Checked the interior fuse panel and all is fine.
Everything in these places is getting voltage.

Here is something we (my good neighbor and I) noticed during this
testing and starting attempts...

If you turn the ignition to the RUN position, four dash lights should
come on. 1) ABS, 2) Check Engine, 3)Airbag and 4) Seatbelt.

If you turn the key to RUN, and the "Check Engine" light comes on, the
jeep will start. If the "Check Engine" light does not come on, the
jeep will NOT start. If you put the key in the RUN position and the
"check engine" light does not come on, AND you leave the key in the
RUN position, eventually the "Check Engine" light comes on and the
jeep starts. Every time the "Check Engine" light comes on, you can
hear the fuel pump prime and start the jeep, usually on the first try.

We repeated this pattern for a good 30-60 minutes, giving different
time intervals inbetween because sometimes the dash lights all come on
as they should on the first trr, and we wanted to make sure it wasn't
initial luck. We confirmed there is a definite pattern.

On the very last attempt, it took longer for the light to come on.. at
least another 20 seconds than all the other previous attempts, AND
when the "Check Engine" light came on, so did the Security light. The
Security light remains on for about 3-5 seconds and then went off.

I know the system is running checks when the light is on, and
sometimes something isn't letting it come on, ergo no checks and
nofuel priming. Anyone ever see this before?

Last note.. sometimes, and only sometimes, I hear a clicking when I
turn the key to RUN. It sounds like a circuit switching on/off. During
all this testing, I did not hear it once.



>On Fri, 17 Feb 2006 16:54:11 -0600, "DougW" wrote:
>Let's go over the basics then.
>
>From the front of the vehicle, remove the fuel pump relay
>Looking into the hole:
>
> 7
> |
>
>6| -8- |10
>
> -9-
>
>With the ignition on, hole 7 should
>have 12V from the power center fuses 3(20A) and 15(30A)
>(same location as the relays)
>Also check fuse2(20A), the ASD power fuse.
>
>Hole 6 should also have 12V, if not check fuse 6(15A)
>
>Hole 9 feeds the pump and the heated O2 sensor
>(If you found blown fuses take a look at the O2 sensor
>and follow the wire back along the engine to where a clip
>holds it to the block, then follow that wire up to another
>clip up above and forward of the engine mount. sometimes
>that wire will melt and short out. That short can/will blow
>fuses.)
>
>If all looks good at this point then
>Jumping pin 9 to pin 7 will turn the pump on.
>
>You should be able to hear it or watch the fuel rail
>pressure jump.

 

Ok, here's the current situation...

Tested all the relays and engine compartment fuse/relay box and they
are all fine. Checked the interior fuse panel and all is fine.
Everything in these places is getting voltage.

Here is something we (my good neighbor and I) noticed during this
testing and starting attempts...

If you turn the ignition to the RUN position, four dash lights should
come on. 1) ABS, 2) Check Engine, 3)Airbag and 4) Seatbelt.

If you turn the key to RUN, and the "Check Engine" light comes on, the
jeep will start. If the "Check Engine" light does not come on, the
jeep will NOT start. If you put the key in the RUN position and the
"check engine" light does not come on, AND you leave the key in the
RUN position, eventually the "Check Engine" light comes on and the
jeep starts. Every time the "Check Engine" light comes on, you can
hear the fuel pump prime and start the jeep, usually on the first try.

We repeated this pattern for a good 30-60 minutes, giving different
time intervals inbetween because sometimes the dash lights all come on
as they should on the first trr, and we wanted to make sure it wasn't
initial luck. We confirmed there is a definite pattern.

On the very last attempt, it took longer for the light to come on.. at
least another 20 seconds than all the other previous attempts, AND
when the "Check Engine" light came on, so did the Security light. The
Security light remains on for about 3-5 seconds and then went off.

I know the system is running checks when the light is on, and
sometimes something isn't letting it come on, ergo no checks and
nofuel priming. Anyone ever see this before?

Last note.. sometimes, and only sometimes, I hear a clicking when I
turn the key to RUN. It sounds like a circuit switching on/off. During
all this testing, I did not hear it once.



>On Fri, 17 Feb 2006 16:54:11 -0600, "DougW" wrote:
>Let's go over the basics then.
>
>From the front of the vehicle, remove the fuel pump relay
>Looking into the hole:
>
> 7
> |
>
>6| -8- |10
>
> -9-
>
>With the ignition on, hole 7 should
>have 12V from the power center fuses 3(20A) and 15(30A)
>(same location as the relays)
>Also check fuse2(20A), the ASD power fuse.
>
>Hole 6 should also have 12V, if not check fuse 6(15A)
>
>Hole 9 feeds the pump and the heated O2 sensor
>(If you found blown fuses take a look at the O2 sensor
>and follow the wire back along the engine to where a clip
>holds it to the block, then follow that wire up to another
>clip up above and forward of the engine mount. sometimes
>that wire will melt and short out. That short can/will blow
>fuses.)
>
>If all looks good at this point then
>Jumping pin 9 to pin 7 will turn the pump on.
>
>You should be able to hear it or watch the fuel rail
>pressure jump.