94 Caravan - fuel pump won't run

Daniel J. Stern wrote:
>
> Remove the 60-pin connector from the SBEC and inspect the pins and
sockets
> for corrosion; clean the pins by pushing a pencil eraser straight
down
> onto each pin, and packing the sockets full of Ox-Gard or Noalox.
>
> Check all of the fusible links carefully; it sounds like one or more
of
> them may have popped. Of course if this is the case you'll have to
find
> the cause or the new link will pop, too.
>
>
> To check the computer codes:
>
> With the engine off, switch the ignition key on-off-on-off-on,
> leaving it "ON". Do not
> go to "start", just "on" during this procedure.
>
> Watch the "Check Engine" or "Power Loss" light. It will turn on,
then go
> off, then will begin to flash-out any trouble codes that have been
stored.

Update: removed the SBEC connector and cleaned it, didn't see any
signs of corrosion. While I had access, I unplugged and replugged all
the electrical connectors under the battery. Then put everything back
together. Still no fuel pump. Tried to get the codes to flash.
Several times. Nothing. Jumpered the fuel pump relay so the pump runs
whenever the key is on. Won't start. That indicates to me that
there's no spark. Verified that with a timing light. So am I down to
fusible links? The only one I saw was one to the alternator, so I must
not know where to look. Seems strange that the computer won't blink,
though - it should at least give the 55=end of codes, right? I'll go
back at it tomorrow, check any fusible links and the wiring to the
distributor.

KC

On Fri, 17 Dec 2004 wrote:

> Update: removed the SBEC connector and cleaned it, didn't see any
> signs of corrosion. While I had access, I unplugged and replugged all
> the electrical connectors under the battery. Then put everything back
> together. Still no fuel pump. Tried to get the codes to flash.
> Several times. Nothing.

Excellent indication that you've got a blown fusible link upstream of the
SBEC. Common causes of this include (but are not limited to):

-Oxygen sensor wires shorts to one another or to ground (can happen if
they fall on the hot exhaust manifold)

-Radiator or condenser fan motor seizes

> Seems strange that the computer won't blink,
> though - it should at least give the 55=end of codes, right?

Not if it's not getting power, which it evidently is not!

Let's make sure we're not jumping the gun, though -- check the pull-apart
main disconnect in the positive battery cable about 5 inches down from the
battery terminal. It feeds everything *except* the starter. Lift its
locking tab and pull it apart. If it is internally broken and/or corroded,
clean it up or replace the battery cable assembly.

DS

On Fri, 17 Dec 2004 wrote:

> Update: removed the SBEC connector and cleaned it, didn't see any
> signs of corrosion. While I had access, I unplugged and replugged all
> the electrical connectors under the battery. Then put everything back
> together. Still no fuel pump. Tried to get the codes to flash.
> Several times. Nothing.

Excellent indication that you've got a blown fusible link upstream of the
SBEC. Common causes of this include (but are not limited to):

-Oxygen sensor wires shorts to one another or to ground (can happen if
they fall on the hot exhaust manifold)

-Radiator or condenser fan motor seizes

> Seems strange that the computer won't blink,
> though - it should at least give the 55=end of codes, right?

Not if it's not getting power, which it evidently is not!

Let's make sure we're not jumping the gun, though -- check the pull-apart
main disconnect in the positive battery cable about 5 inches down from the
battery terminal. It feeds everything *except* the starter. Lift its
locking tab and pull it apart. If it is internally broken and/or corroded,
clean it up or replace the battery cable assembly.

DS

Daniel J. Stern wrote:
>
> Excellent indication that you've got a blown fusible link upstream of
the
> SBEC. Common causes of this include (but are not limited to):

>
> Let's make sure we're not jumping the gun, though -- check the
pull-apart
> main disconnect in the positive battery cable about 5 inches down
from the
> battery terminal. It feeds everything *except* the starter. Lift its
> locking tab and pull it apart. If it is internally broken and/or
corroded,
> clean it up or replace the battery cable assembly.
>
> DS

I don't find that on mine. The clamp has 2 cables - one goes to the
starter, the other to the fuse block, with a junction there to another
large wire that goes to the alternator. So everything but the starter
must be fed from the fuse block. Sounds like I should look between the
fuse block and the SBEC for a fusible link, somewhere inside that wire
bundle. Or does it run to the fuse block under the dash before it
comes back to the SBEC? Seems like a bit of a mess until I look under
the dash of my 95 Isuzu Trooper, then it seems like a model of
simplicity by comparison!

KC

Daniel J. Stern wrote:
>
> Excellent indication that you've got a blown fusible link upstream of
the
> SBEC. Common causes of this include (but are not limited to):

>
> Let's make sure we're not jumping the gun, though -- check the
pull-apart
> main disconnect in the positive battery cable about 5 inches down
from the
> battery terminal. It feeds everything *except* the starter. Lift its
> locking tab and pull it apart. If it is internally broken and/or
corroded,
> clean it up or replace the battery cable assembly.
>
> DS

I don't find that on mine. The clamp has 2 cables - one goes to the
starter, the other to the fuse block, with a junction there to another
large wire that goes to the alternator. So everything but the starter
must be fed from the fuse block. Sounds like I should look between the
fuse block and the SBEC for a fusible link, somewhere inside that wire
bundle. Or does it run to the fuse block under the dash before it
comes back to the SBEC? Seems like a bit of a mess until I look under
the dash of my 95 Isuzu Trooper, then it seems like a model of
simplicity by comparison!

KC

On Fri, 17 Dec 2004 wrote:

> > Let's make sure we're not jumping the gun, though -- check the
> > pull-apart
> > main disconnect in the positive battery cable about 5 inches down
> > from the
> > battery terminal.

> I don't find that on mine.

It's possible someone replaced the cable in the past with a non-factory
item. The factory cable assembly has the plastic pull-apart disconnect.

> starter, the other to the fuse block, with a junction there to another
> large wire that goes to the alternator. So everything but the starter
> must be fed from the fuse block.

Check for power at the fuse block!

> Sounds like I should look between the
> fuse block and the SBEC for a fusible link, somewhere inside that wire
> bundle.

Yep. Probably orange or white.

DS

On Fri, 17 Dec 2004 wrote:

> > Let's make sure we're not jumping the gun, though -- check the
> > pull-apart
> > main disconnect in the positive battery cable about 5 inches down
> > from the
> > battery terminal.

> I don't find that on mine.

It's possible someone replaced the cable in the past with a non-factory
item. The factory cable assembly has the plastic pull-apart disconnect.

> starter, the other to the fuse block, with a junction there to another
> large wire that goes to the alternator. So everything but the starter
> must be fed from the fuse block.

Check for power at the fuse block!

> Sounds like I should look between the
> fuse block and the SBEC for a fusible link, somewhere inside that wire
> bundle.

Yep. Probably orange or white.

DS

wrote:

> Daniel J. Stern wrote:
>
>>Excellent indication that you've got a blown fusible link upstream of
>
> the
>
>>SBEC. Common causes of this include (but are not limited to):
>
>
>>Let's make sure we're not jumping the gun, though -- check the
>
> pull-apart
>
>>main disconnect in the positive battery cable about 5 inches down
>
> from the
>
>>battery terminal. It feeds everything *except* the starter. Lift its
>>locking tab and pull it apart. If it is internally broken and/or
>
> corroded,
>
>>clean it up or replace the battery cable assembly.
>>
>>DS
>
>
> I don't find that on mine. The clamp has 2 cables - one goes to the
> starter, the other to the fuse block, with a junction there to another
> large wire that goes to the alternator. So everything but the starter
> must be fed from the fuse block. Sounds like I should look between the
> fuse block and the SBEC for a fusible link, somewhere inside that wire
> bundle. Or does it run to the fuse block under the dash before it
> comes back to the SBEC? Seems like a bit of a mess until I look under
> the dash of my 95 Isuzu Trooper, then it seems like a model of
> simplicity by comparison!
>
> KC
>

Might be faster to first use a multimeter to check for voltage on the
supply pin to the computer. That is faster than tearing into a bundle
of wires.


Matt

wrote:

> Daniel J. Stern wrote:
>
>>Excellent indication that you've got a blown fusible link upstream of
>
> the
>
>>SBEC. Common causes of this include (but are not limited to):
>
>
>>Let's make sure we're not jumping the gun, though -- check the
>
> pull-apart
>
>>main disconnect in the positive battery cable about 5 inches down
>
> from the
>
>>battery terminal. It feeds everything *except* the starter. Lift its
>>locking tab and pull it apart. If it is internally broken and/or
>
> corroded,
>
>>clean it up or replace the battery cable assembly.
>>
>>DS
>
>
> I don't find that on mine. The clamp has 2 cables - one goes to the
> starter, the other to the fuse block, with a junction there to another
> large wire that goes to the alternator. So everything but the starter
> must be fed from the fuse block. Sounds like I should look between the
> fuse block and the SBEC for a fusible link, somewhere inside that wire
> bundle. Or does it run to the fuse block under the dash before it
> comes back to the SBEC? Seems like a bit of a mess until I look under
> the dash of my 95 Isuzu Trooper, then it seems like a model of
> simplicity by comparison!
>
> KC
>

Might be faster to first use a multimeter to check for voltage on the
supply pin to the computer. That is faster than tearing into a bundle
of wires.


Matt

(((Just curious - what is it that tells the fuel pump to quit pumping
before the engine starts?))) If the PCM doesnt see that the engine is
running after 3 seconds, it shuts down fuel and spark thru the ASD relay,
You know that you are getting fuel but possibly loosin spark, go to the
windshiled wiper resorvoir and under neath it is where you will locate the
fusible links, look at them and gently pull on each one to see if any are
broken/burnt.If all ok
Check b+ to PCM with a test light for voltage.If ok Check the 5 volt power
supply to the sensors for a short to ground. A short to ground on the 5 volt
power supply to sensors such as: MAP, TPS, A/C PRESSURE TRANSDUCER, EGR
POSITION, etc. will cause the vehicle to die out and may cause the PCM to be
a no response. All this of course would be easier using a scan tool to see
acuall values and be able to acuate spark and fuel systems, so taking it to
a repair facility may be the next option. Good Luck
Glenn Beasley
Chrysler Tech


> wrote in message
oups.com...
>
> Daniel J. Stern wrote:
> >
> > Remove the 60-pin connector from the SBEC and inspect the pins and
> sockets
> > for corrosion; clean the pins by pushing a pencil eraser straight
> down
> > onto each pin, and packing the sockets full of Ox-Gard or Noalox.
> >
> > Check all of the fusible links carefully; it sounds like one or more
> of
> > them may have popped. Of course if this is the case you'll have to
> find
> > the cause or the new link will pop, too.
> >
> > Check the codes and report what you find.
>
> Thanks for the tips, Daniel. I'll try these tonight and hopefully get
> it going. I wanted to donate it to my church (they in turn donate it
> to those who need cars but can't afford them), but they won't take it
> if it isn't running. And since I can't sell it (tried twice, can't
> even get an offer at $800, and it's in pretty good shape), and it's not
> doing me any good sitting in my driveway, this seemed like a good
> option.
>
> Just curious - what is it that tells the fuel pump to quit pumping
> before the engine starts? The pressure regulator only holds the
> pressure at a certain level and returns the excess back to the tank,
> right? But that's with the pump running continuously. Something tells
> it to stop when the key is on but the engine's not running.
>
> KC
>