Fuel Guage not working
05-02-2006, 11:48 PM
#1
Guest
Posts: n/a
Fuel Guage not working
I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
stopped working. It always reads zero or almost zero.The rest of the
guages working OK. My guess is the sending unit. Any other likely
possibilities. The dealer wanted nearly $250 for A new sender (not
including installation) This seems a bit high to me, more like the price
for the FI unit that includes the pump. Is there anyway to isolate the
problem to the guage itself rather than the sender. If it is important,
the guage does move slightly to the right when the power is turned on,
but only gets to empty.
So assuming it is the sender and I can find one, any tips on dropping
the tank. Also is there any way to tell the difference between the 14.5
gallon tank and the 20. Pretty sure I have the smaller tank, but I never
let it get very low, so I am not sure.
Aloha from Maui
Joe
stopped working. It always reads zero or almost zero.The rest of the
guages working OK. My guess is the sending unit. Any other likely
possibilities. The dealer wanted nearly $250 for A new sender (not
including installation) This seems a bit high to me, more like the price
for the FI unit that includes the pump. Is there anyway to isolate the
problem to the guage itself rather than the sender. If it is important,
the guage does move slightly to the right when the power is turned on,
but only gets to empty.
So assuming it is the sender and I can find one, any tips on dropping
the tank. Also is there any way to tell the difference between the 14.5
gallon tank and the 20. Pretty sure I have the smaller tank, but I never
let it get very low, so I am not sure.
Aloha from Maui
Joe
05-03-2006, 01:20 AM
#2
Guest
Posts: n/a
Re: Fuel Guage not working
Hi Joe,
Years ago there was some warranty work around the tank that
required pulling a bracket with sending unit's ground wire attached,
that was often forgotten upon reattachment, maybe yours came loose. At
least put a volt meter back there and trouble shoot.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
Joe and Joann wrote:
>
> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
> stopped working. It always reads zero or almost zero.The rest of the
> guages working OK. My guess is the sending unit. Any other likely
> possibilities. The dealer wanted nearly $250 for A new sender (not
> including installation) This seems a bit high to me, more like the price
> for the FI unit that includes the pump. Is there anyway to isolate the
> problem to the guage itself rather than the sender. If it is important,
> the guage does move slightly to the right when the power is turned on,
> but only gets to empty.
>
> So assuming it is the sender and I can find one, any tips on dropping
> the tank. Also is there any way to tell the difference between the 14.5
> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
> let it get very low, so I am not sure.
>
> Aloha from Maui
> Joe
Years ago there was some warranty work around the tank that
required pulling a bracket with sending unit's ground wire attached,
that was often forgotten upon reattachment, maybe yours came loose. At
least put a volt meter back there and trouble shoot.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
Joe and Joann wrote:
>
> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
> stopped working. It always reads zero or almost zero.The rest of the
> guages working OK. My guess is the sending unit. Any other likely
> possibilities. The dealer wanted nearly $250 for A new sender (not
> including installation) This seems a bit high to me, more like the price
> for the FI unit that includes the pump. Is there anyway to isolate the
> problem to the guage itself rather than the sender. If it is important,
> the guage does move slightly to the right when the power is turned on,
> but only gets to empty.
>
> So assuming it is the sender and I can find one, any tips on dropping
> the tank. Also is there any way to tell the difference between the 14.5
> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
> let it get very low, so I am not sure.
>
> Aloha from Maui
> Joe
05-03-2006, 01:20 AM
#3
Guest
Posts: n/a
Re: Fuel Guage not working
Hi Joe,
Years ago there was some warranty work around the tank that
required pulling a bracket with sending unit's ground wire attached,
that was often forgotten upon reattachment, maybe yours came loose. At
least put a volt meter back there and trouble shoot.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
Joe and Joann wrote:
>
> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
> stopped working. It always reads zero or almost zero.The rest of the
> guages working OK. My guess is the sending unit. Any other likely
> possibilities. The dealer wanted nearly $250 for A new sender (not
> including installation) This seems a bit high to me, more like the price
> for the FI unit that includes the pump. Is there anyway to isolate the
> problem to the guage itself rather than the sender. If it is important,
> the guage does move slightly to the right when the power is turned on,
> but only gets to empty.
>
> So assuming it is the sender and I can find one, any tips on dropping
> the tank. Also is there any way to tell the difference between the 14.5
> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
> let it get very low, so I am not sure.
>
> Aloha from Maui
> Joe
Years ago there was some warranty work around the tank that
required pulling a bracket with sending unit's ground wire attached,
that was often forgotten upon reattachment, maybe yours came loose. At
least put a volt meter back there and trouble shoot.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
Joe and Joann wrote:
>
> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
> stopped working. It always reads zero or almost zero.The rest of the
> guages working OK. My guess is the sending unit. Any other likely
> possibilities. The dealer wanted nearly $250 for A new sender (not
> including installation) This seems a bit high to me, more like the price
> for the FI unit that includes the pump. Is there anyway to isolate the
> problem to the guage itself rather than the sender. If it is important,
> the guage does move slightly to the right when the power is turned on,
> but only gets to empty.
>
> So assuming it is the sender and I can find one, any tips on dropping
> the tank. Also is there any way to tell the difference between the 14.5
> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
> let it get very low, so I am not sure.
>
> Aloha from Maui
> Joe
05-03-2006, 01:20 AM
#4
Guest
Posts: n/a
Re: Fuel Guage not working
Hi Joe,
Years ago there was some warranty work around the tank that
required pulling a bracket with sending unit's ground wire attached,
that was often forgotten upon reattachment, maybe yours came loose. At
least put a volt meter back there and trouble shoot.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
Joe and Joann wrote:
>
> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
> stopped working. It always reads zero or almost zero.The rest of the
> guages working OK. My guess is the sending unit. Any other likely
> possibilities. The dealer wanted nearly $250 for A new sender (not
> including installation) This seems a bit high to me, more like the price
> for the FI unit that includes the pump. Is there anyway to isolate the
> problem to the guage itself rather than the sender. If it is important,
> the guage does move slightly to the right when the power is turned on,
> but only gets to empty.
>
> So assuming it is the sender and I can find one, any tips on dropping
> the tank. Also is there any way to tell the difference between the 14.5
> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
> let it get very low, so I am not sure.
>
> Aloha from Maui
> Joe
Years ago there was some warranty work around the tank that
required pulling a bracket with sending unit's ground wire attached,
that was often forgotten upon reattachment, maybe yours came loose. At
least put a volt meter back there and trouble shoot.
God Bless America, Bill O|||||||O
mailto:-------------------- http://www.----------.com/
Joe and Joann wrote:
>
> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
> stopped working. It always reads zero or almost zero.The rest of the
> guages working OK. My guess is the sending unit. Any other likely
> possibilities. The dealer wanted nearly $250 for A new sender (not
> including installation) This seems a bit high to me, more like the price
> for the FI unit that includes the pump. Is there anyway to isolate the
> problem to the guage itself rather than the sender. If it is important,
> the guage does move slightly to the right when the power is turned on,
> but only gets to empty.
>
> So assuming it is the sender and I can find one, any tips on dropping
> the tank. Also is there any way to tell the difference between the 14.5
> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
> let it get very low, so I am not sure.
>
> Aloha from Maui
> Joe
05-03-2006, 01:26 AM
#5
Guest
Posts: n/a
Re: Fuel Guage not working
The sender unit consists of a float attached to a moveable arm, that moves a
variable resistor. The electrical resistance at the sender unit terminals
will change as the arm is moved. I can tell you right now, that the Haynes
Automotive Repair Manual that I have, part number 50030 (1777), for the 1987
through 1995 Jeep Wrangler, does not contain the resistance values, that you
need to test the sender unit. :o( A cursory scan of that section of the
manual indicates, that it may be useful for removing the tank. I suggest
removing the tank, to inspect the sender unit. :o(
The sender unit is tested electrically, by moving the arm with a DVOM (Drive
Vehicle Off Mountain or Digital Volt Ohm Meter, I can't remember which)
attached to the sender unit terminals. The resistance should change
smoothly as the arm is moved. Lacking the specifications, I can't tell you
more. If the float is saturated or full of fuel, it will feel heavy or make
a sloshing sound.
Other suspects are a faulty electrical connection at the fuel pump/sender
unit connector, a fault in the wiring to the sender unit, and a bad gauge.
If you can identify and access the wires to the sender unit (Haynes wiring
diagrams are pretty bad too) then you can check for voltage to the sender
unit with the key on. We used to short the terminal to ground, and watch
the gauge go to full, on some older vehicles, but I do not know whether this
is recommended for your vehicle. The Haynes manual is short on
troubleshooting tips in this area.
It does sound as if the price quoted, is for a sender/fuel pump unit. They
appear to be a single unit. On vehicles with a 20 gallon tank, the fuel
pump/sender unit is mounted with eight screws. The fifteen gallon tank has
a lock ring. The Haynes manual says "if the ring is difficult to remove,
tap it loose with a wood dowel or brass punch and a small mallet (DO NOT use
a steel punch, or you could cause an explosion!)" They show a steel
screwdriver being used.
The behavior of your gauge is consistent with a flooded float, but not a
100% indication. On my old Plymouth Valiant, this was a fifteen minute job,
if the tank was below one quarter full. Things sure have changed. My
advice is to get some penetrating oil on the tank mounting bolts, a couple
of days before you try dropping the tank.
Earle
"Joe and Joann" <mauijoeb@removehawaii.rr.com> wrote in message
news:EKV5g.11377$MP2.1636@tornado.socal.rr.com...
> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
> stopped working. It always reads zero or almost zero.The rest of the
> guages working OK. My guess is the sending unit. Any other likely
> possibilities. The dealer wanted nearly $250 for A new sender (not
> including installation) This seems a bit high to me, more like the price
> for the FI unit that includes the pump. Is there anyway to isolate the
> problem to the guage itself rather than the sender. If it is important,
> the guage does move slightly to the right when the power is turned on,
> but only gets to empty.
>
> So assuming it is the sender and I can find one, any tips on dropping
> the tank. Also is there any way to tell the difference between the 14.5
> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
> let it get very low, so I am not sure.
>
> Aloha from Maui
> Joe
variable resistor. The electrical resistance at the sender unit terminals
will change as the arm is moved. I can tell you right now, that the Haynes
Automotive Repair Manual that I have, part number 50030 (1777), for the 1987
through 1995 Jeep Wrangler, does not contain the resistance values, that you
need to test the sender unit. :o( A cursory scan of that section of the
manual indicates, that it may be useful for removing the tank. I suggest
removing the tank, to inspect the sender unit. :o(
The sender unit is tested electrically, by moving the arm with a DVOM (Drive
Vehicle Off Mountain or Digital Volt Ohm Meter, I can't remember which)
attached to the sender unit terminals. The resistance should change
smoothly as the arm is moved. Lacking the specifications, I can't tell you
more. If the float is saturated or full of fuel, it will feel heavy or make
a sloshing sound.
Other suspects are a faulty electrical connection at the fuel pump/sender
unit connector, a fault in the wiring to the sender unit, and a bad gauge.
If you can identify and access the wires to the sender unit (Haynes wiring
diagrams are pretty bad too) then you can check for voltage to the sender
unit with the key on. We used to short the terminal to ground, and watch
the gauge go to full, on some older vehicles, but I do not know whether this
is recommended for your vehicle. The Haynes manual is short on
troubleshooting tips in this area.
It does sound as if the price quoted, is for a sender/fuel pump unit. They
appear to be a single unit. On vehicles with a 20 gallon tank, the fuel
pump/sender unit is mounted with eight screws. The fifteen gallon tank has
a lock ring. The Haynes manual says "if the ring is difficult to remove,
tap it loose with a wood dowel or brass punch and a small mallet (DO NOT use
a steel punch, or you could cause an explosion!)" They show a steel
screwdriver being used.
The behavior of your gauge is consistent with a flooded float, but not a
100% indication. On my old Plymouth Valiant, this was a fifteen minute job,
if the tank was below one quarter full. Things sure have changed. My
advice is to get some penetrating oil on the tank mounting bolts, a couple
of days before you try dropping the tank.
Earle
"Joe and Joann" <mauijoeb@removehawaii.rr.com> wrote in message
news:EKV5g.11377$MP2.1636@tornado.socal.rr.com...
> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
> stopped working. It always reads zero or almost zero.The rest of the
> guages working OK. My guess is the sending unit. Any other likely
> possibilities. The dealer wanted nearly $250 for A new sender (not
> including installation) This seems a bit high to me, more like the price
> for the FI unit that includes the pump. Is there anyway to isolate the
> problem to the guage itself rather than the sender. If it is important,
> the guage does move slightly to the right when the power is turned on,
> but only gets to empty.
>
> So assuming it is the sender and I can find one, any tips on dropping
> the tank. Also is there any way to tell the difference between the 14.5
> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
> let it get very low, so I am not sure.
>
> Aloha from Maui
> Joe
05-03-2006, 01:26 AM
#6
Guest
Posts: n/a
Re: Fuel Guage not working
The sender unit consists of a float attached to a moveable arm, that moves a
variable resistor. The electrical resistance at the sender unit terminals
will change as the arm is moved. I can tell you right now, that the Haynes
Automotive Repair Manual that I have, part number 50030 (1777), for the 1987
through 1995 Jeep Wrangler, does not contain the resistance values, that you
need to test the sender unit. :o( A cursory scan of that section of the
manual indicates, that it may be useful for removing the tank. I suggest
removing the tank, to inspect the sender unit. :o(
The sender unit is tested electrically, by moving the arm with a DVOM (Drive
Vehicle Off Mountain or Digital Volt Ohm Meter, I can't remember which)
attached to the sender unit terminals. The resistance should change
smoothly as the arm is moved. Lacking the specifications, I can't tell you
more. If the float is saturated or full of fuel, it will feel heavy or make
a sloshing sound.
Other suspects are a faulty electrical connection at the fuel pump/sender
unit connector, a fault in the wiring to the sender unit, and a bad gauge.
If you can identify and access the wires to the sender unit (Haynes wiring
diagrams are pretty bad too) then you can check for voltage to the sender
unit with the key on. We used to short the terminal to ground, and watch
the gauge go to full, on some older vehicles, but I do not know whether this
is recommended for your vehicle. The Haynes manual is short on
troubleshooting tips in this area.
It does sound as if the price quoted, is for a sender/fuel pump unit. They
appear to be a single unit. On vehicles with a 20 gallon tank, the fuel
pump/sender unit is mounted with eight screws. The fifteen gallon tank has
a lock ring. The Haynes manual says "if the ring is difficult to remove,
tap it loose with a wood dowel or brass punch and a small mallet (DO NOT use
a steel punch, or you could cause an explosion!)" They show a steel
screwdriver being used.
The behavior of your gauge is consistent with a flooded float, but not a
100% indication. On my old Plymouth Valiant, this was a fifteen minute job,
if the tank was below one quarter full. Things sure have changed. My
advice is to get some penetrating oil on the tank mounting bolts, a couple
of days before you try dropping the tank.
Earle
"Joe and Joann" <mauijoeb@removehawaii.rr.com> wrote in message
news:EKV5g.11377$MP2.1636@tornado.socal.rr.com...
> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
> stopped working. It always reads zero or almost zero.The rest of the
> guages working OK. My guess is the sending unit. Any other likely
> possibilities. The dealer wanted nearly $250 for A new sender (not
> including installation) This seems a bit high to me, more like the price
> for the FI unit that includes the pump. Is there anyway to isolate the
> problem to the guage itself rather than the sender. If it is important,
> the guage does move slightly to the right when the power is turned on,
> but only gets to empty.
>
> So assuming it is the sender and I can find one, any tips on dropping
> the tank. Also is there any way to tell the difference between the 14.5
> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
> let it get very low, so I am not sure.
>
> Aloha from Maui
> Joe
variable resistor. The electrical resistance at the sender unit terminals
will change as the arm is moved. I can tell you right now, that the Haynes
Automotive Repair Manual that I have, part number 50030 (1777), for the 1987
through 1995 Jeep Wrangler, does not contain the resistance values, that you
need to test the sender unit. :o( A cursory scan of that section of the
manual indicates, that it may be useful for removing the tank. I suggest
removing the tank, to inspect the sender unit. :o(
The sender unit is tested electrically, by moving the arm with a DVOM (Drive
Vehicle Off Mountain or Digital Volt Ohm Meter, I can't remember which)
attached to the sender unit terminals. The resistance should change
smoothly as the arm is moved. Lacking the specifications, I can't tell you
more. If the float is saturated or full of fuel, it will feel heavy or make
a sloshing sound.
Other suspects are a faulty electrical connection at the fuel pump/sender
unit connector, a fault in the wiring to the sender unit, and a bad gauge.
If you can identify and access the wires to the sender unit (Haynes wiring
diagrams are pretty bad too) then you can check for voltage to the sender
unit with the key on. We used to short the terminal to ground, and watch
the gauge go to full, on some older vehicles, but I do not know whether this
is recommended for your vehicle. The Haynes manual is short on
troubleshooting tips in this area.
It does sound as if the price quoted, is for a sender/fuel pump unit. They
appear to be a single unit. On vehicles with a 20 gallon tank, the fuel
pump/sender unit is mounted with eight screws. The fifteen gallon tank has
a lock ring. The Haynes manual says "if the ring is difficult to remove,
tap it loose with a wood dowel or brass punch and a small mallet (DO NOT use
a steel punch, or you could cause an explosion!)" They show a steel
screwdriver being used.
The behavior of your gauge is consistent with a flooded float, but not a
100% indication. On my old Plymouth Valiant, this was a fifteen minute job,
if the tank was below one quarter full. Things sure have changed. My
advice is to get some penetrating oil on the tank mounting bolts, a couple
of days before you try dropping the tank.
Earle
"Joe and Joann" <mauijoeb@removehawaii.rr.com> wrote in message
news:EKV5g.11377$MP2.1636@tornado.socal.rr.com...
> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
> stopped working. It always reads zero or almost zero.The rest of the
> guages working OK. My guess is the sending unit. Any other likely
> possibilities. The dealer wanted nearly $250 for A new sender (not
> including installation) This seems a bit high to me, more like the price
> for the FI unit that includes the pump. Is there anyway to isolate the
> problem to the guage itself rather than the sender. If it is important,
> the guage does move slightly to the right when the power is turned on,
> but only gets to empty.
>
> So assuming it is the sender and I can find one, any tips on dropping
> the tank. Also is there any way to tell the difference between the 14.5
> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
> let it get very low, so I am not sure.
>
> Aloha from Maui
> Joe
05-03-2006, 01:26 AM
#7
Guest
Posts: n/a
Re: Fuel Guage not working
The sender unit consists of a float attached to a moveable arm, that moves a
variable resistor. The electrical resistance at the sender unit terminals
will change as the arm is moved. I can tell you right now, that the Haynes
Automotive Repair Manual that I have, part number 50030 (1777), for the 1987
through 1995 Jeep Wrangler, does not contain the resistance values, that you
need to test the sender unit. :o( A cursory scan of that section of the
manual indicates, that it may be useful for removing the tank. I suggest
removing the tank, to inspect the sender unit. :o(
The sender unit is tested electrically, by moving the arm with a DVOM (Drive
Vehicle Off Mountain or Digital Volt Ohm Meter, I can't remember which)
attached to the sender unit terminals. The resistance should change
smoothly as the arm is moved. Lacking the specifications, I can't tell you
more. If the float is saturated or full of fuel, it will feel heavy or make
a sloshing sound.
Other suspects are a faulty electrical connection at the fuel pump/sender
unit connector, a fault in the wiring to the sender unit, and a bad gauge.
If you can identify and access the wires to the sender unit (Haynes wiring
diagrams are pretty bad too) then you can check for voltage to the sender
unit with the key on. We used to short the terminal to ground, and watch
the gauge go to full, on some older vehicles, but I do not know whether this
is recommended for your vehicle. The Haynes manual is short on
troubleshooting tips in this area.
It does sound as if the price quoted, is for a sender/fuel pump unit. They
appear to be a single unit. On vehicles with a 20 gallon tank, the fuel
pump/sender unit is mounted with eight screws. The fifteen gallon tank has
a lock ring. The Haynes manual says "if the ring is difficult to remove,
tap it loose with a wood dowel or brass punch and a small mallet (DO NOT use
a steel punch, or you could cause an explosion!)" They show a steel
screwdriver being used.
The behavior of your gauge is consistent with a flooded float, but not a
100% indication. On my old Plymouth Valiant, this was a fifteen minute job,
if the tank was below one quarter full. Things sure have changed. My
advice is to get some penetrating oil on the tank mounting bolts, a couple
of days before you try dropping the tank.
Earle
"Joe and Joann" <mauijoeb@removehawaii.rr.com> wrote in message
news:EKV5g.11377$MP2.1636@tornado.socal.rr.com...
> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
> stopped working. It always reads zero or almost zero.The rest of the
> guages working OK. My guess is the sending unit. Any other likely
> possibilities. The dealer wanted nearly $250 for A new sender (not
> including installation) This seems a bit high to me, more like the price
> for the FI unit that includes the pump. Is there anyway to isolate the
> problem to the guage itself rather than the sender. If it is important,
> the guage does move slightly to the right when the power is turned on,
> but only gets to empty.
>
> So assuming it is the sender and I can find one, any tips on dropping
> the tank. Also is there any way to tell the difference between the 14.5
> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
> let it get very low, so I am not sure.
>
> Aloha from Maui
> Joe
variable resistor. The electrical resistance at the sender unit terminals
will change as the arm is moved. I can tell you right now, that the Haynes
Automotive Repair Manual that I have, part number 50030 (1777), for the 1987
through 1995 Jeep Wrangler, does not contain the resistance values, that you
need to test the sender unit. :o( A cursory scan of that section of the
manual indicates, that it may be useful for removing the tank. I suggest
removing the tank, to inspect the sender unit. :o(
The sender unit is tested electrically, by moving the arm with a DVOM (Drive
Vehicle Off Mountain or Digital Volt Ohm Meter, I can't remember which)
attached to the sender unit terminals. The resistance should change
smoothly as the arm is moved. Lacking the specifications, I can't tell you
more. If the float is saturated or full of fuel, it will feel heavy or make
a sloshing sound.
Other suspects are a faulty electrical connection at the fuel pump/sender
unit connector, a fault in the wiring to the sender unit, and a bad gauge.
If you can identify and access the wires to the sender unit (Haynes wiring
diagrams are pretty bad too) then you can check for voltage to the sender
unit with the key on. We used to short the terminal to ground, and watch
the gauge go to full, on some older vehicles, but I do not know whether this
is recommended for your vehicle. The Haynes manual is short on
troubleshooting tips in this area.
It does sound as if the price quoted, is for a sender/fuel pump unit. They
appear to be a single unit. On vehicles with a 20 gallon tank, the fuel
pump/sender unit is mounted with eight screws. The fifteen gallon tank has
a lock ring. The Haynes manual says "if the ring is difficult to remove,
tap it loose with a wood dowel or brass punch and a small mallet (DO NOT use
a steel punch, or you could cause an explosion!)" They show a steel
screwdriver being used.
The behavior of your gauge is consistent with a flooded float, but not a
100% indication. On my old Plymouth Valiant, this was a fifteen minute job,
if the tank was below one quarter full. Things sure have changed. My
advice is to get some penetrating oil on the tank mounting bolts, a couple
of days before you try dropping the tank.
Earle
"Joe and Joann" <mauijoeb@removehawaii.rr.com> wrote in message
news:EKV5g.11377$MP2.1636@tornado.socal.rr.com...
> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
> stopped working. It always reads zero or almost zero.The rest of the
> guages working OK. My guess is the sending unit. Any other likely
> possibilities. The dealer wanted nearly $250 for A new sender (not
> including installation) This seems a bit high to me, more like the price
> for the FI unit that includes the pump. Is there anyway to isolate the
> problem to the guage itself rather than the sender. If it is important,
> the guage does move slightly to the right when the power is turned on,
> but only gets to empty.
>
> So assuming it is the sender and I can find one, any tips on dropping
> the tank. Also is there any way to tell the difference between the 14.5
> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
> let it get very low, so I am not sure.
>
> Aloha from Maui
> Joe
05-03-2006, 01:32 AM
#8
Guest
Posts: n/a
Re: Fuel Guage not working
Thanks Earl
Since I have the carb 4.2 L with the mechanical pump, I sure don't need
the in the tank pump used on the FI model. Hard to believe that price
isn't for the combined pump/sender unit as you said. Thanks again for
the ideas.
Earle Horton wrote:
> The sender unit consists of a float attached to a moveable arm, that moves a
> variable resistor. The electrical resistance at the sender unit terminals
> will change as the arm is moved. I can tell you right now, that the Haynes
> Automotive Repair Manual that I have, part number 50030 (1777), for the 1987
> through 1995 Jeep Wrangler, does not contain the resistance values, that you
> need to test the sender unit. :o( A cursory scan of that section of the
> manual indicates, that it may be useful for removing the tank. I suggest
> removing the tank, to inspect the sender unit. :o(
>
> The sender unit is tested electrically, by moving the arm with a DVOM (Drive
> Vehicle Off Mountain or Digital Volt Ohm Meter, I can't remember which)
> attached to the sender unit terminals. The resistance should change
> smoothly as the arm is moved. Lacking the specifications, I can't tell you
> more. If the float is saturated or full of fuel, it will feel heavy or make
> a sloshing sound.
>
> Other suspects are a faulty electrical connection at the fuel pump/sender
> unit connector, a fault in the wiring to the sender unit, and a bad gauge.
> If you can identify and access the wires to the sender unit (Haynes wiring
> diagrams are pretty bad too) then you can check for voltage to the sender
> unit with the key on. We used to short the terminal to ground, and watch
> the gauge go to full, on some older vehicles, but I do not know whether this
> is recommended for your vehicle. The Haynes manual is short on
> troubleshooting tips in this area.
>
> It does sound as if the price quoted, is for a sender/fuel pump unit. They
> appear to be a single unit. On vehicles with a 20 gallon tank, the fuel
> pump/sender unit is mounted with eight screws. The fifteen gallon tank has
> a lock ring. The Haynes manual says "if the ring is difficult to remove,
> tap it loose with a wood dowel or brass punch and a small mallet (DO NOT use
> a steel punch, or you could cause an explosion!)" They show a steel
> screwdriver being used.
>
> The behavior of your gauge is consistent with a flooded float, but not a
> 100% indication. On my old Plymouth Valiant, this was a fifteen minute job,
> if the tank was below one quarter full. Things sure have changed. My
> advice is to get some penetrating oil on the tank mounting bolts, a couple
> of days before you try dropping the tank.
>
> Earle
>
> "Joe and Joann" <mauijoeb@removehawaii.rr.com> wrote in message
> news:EKV5g.11377$MP2.1636@tornado.socal.rr.com...
>> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
>> stopped working. It always reads zero or almost zero.The rest of the
>> guages working OK. My guess is the sending unit. Any other likely
>> possibilities. The dealer wanted nearly $250 for A new sender (not
>> including installation) This seems a bit high to me, more like the price
>> for the FI unit that includes the pump. Is there anyway to isolate the
>> problem to the guage itself rather than the sender. If it is important,
>> the guage does move slightly to the right when the power is turned on,
>> but only gets to empty.
>>
>> So assuming it is the sender and I can find one, any tips on dropping
>> the tank. Also is there any way to tell the difference between the 14.5
>> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
>> let it get very low, so I am not sure.
>>
>> Aloha from Maui
>> Joe
>
>
Since I have the carb 4.2 L with the mechanical pump, I sure don't need
the in the tank pump used on the FI model. Hard to believe that price
isn't for the combined pump/sender unit as you said. Thanks again for
the ideas.
Earle Horton wrote:
> The sender unit consists of a float attached to a moveable arm, that moves a
> variable resistor. The electrical resistance at the sender unit terminals
> will change as the arm is moved. I can tell you right now, that the Haynes
> Automotive Repair Manual that I have, part number 50030 (1777), for the 1987
> through 1995 Jeep Wrangler, does not contain the resistance values, that you
> need to test the sender unit. :o( A cursory scan of that section of the
> manual indicates, that it may be useful for removing the tank. I suggest
> removing the tank, to inspect the sender unit. :o(
>
> The sender unit is tested electrically, by moving the arm with a DVOM (Drive
> Vehicle Off Mountain or Digital Volt Ohm Meter, I can't remember which)
> attached to the sender unit terminals. The resistance should change
> smoothly as the arm is moved. Lacking the specifications, I can't tell you
> more. If the float is saturated or full of fuel, it will feel heavy or make
> a sloshing sound.
>
> Other suspects are a faulty electrical connection at the fuel pump/sender
> unit connector, a fault in the wiring to the sender unit, and a bad gauge.
> If you can identify and access the wires to the sender unit (Haynes wiring
> diagrams are pretty bad too) then you can check for voltage to the sender
> unit with the key on. We used to short the terminal to ground, and watch
> the gauge go to full, on some older vehicles, but I do not know whether this
> is recommended for your vehicle. The Haynes manual is short on
> troubleshooting tips in this area.
>
> It does sound as if the price quoted, is for a sender/fuel pump unit. They
> appear to be a single unit. On vehicles with a 20 gallon tank, the fuel
> pump/sender unit is mounted with eight screws. The fifteen gallon tank has
> a lock ring. The Haynes manual says "if the ring is difficult to remove,
> tap it loose with a wood dowel or brass punch and a small mallet (DO NOT use
> a steel punch, or you could cause an explosion!)" They show a steel
> screwdriver being used.
>
> The behavior of your gauge is consistent with a flooded float, but not a
> 100% indication. On my old Plymouth Valiant, this was a fifteen minute job,
> if the tank was below one quarter full. Things sure have changed. My
> advice is to get some penetrating oil on the tank mounting bolts, a couple
> of days before you try dropping the tank.
>
> Earle
>
> "Joe and Joann" <mauijoeb@removehawaii.rr.com> wrote in message
> news:EKV5g.11377$MP2.1636@tornado.socal.rr.com...
>> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
>> stopped working. It always reads zero or almost zero.The rest of the
>> guages working OK. My guess is the sending unit. Any other likely
>> possibilities. The dealer wanted nearly $250 for A new sender (not
>> including installation) This seems a bit high to me, more like the price
>> for the FI unit that includes the pump. Is there anyway to isolate the
>> problem to the guage itself rather than the sender. If it is important,
>> the guage does move slightly to the right when the power is turned on,
>> but only gets to empty.
>>
>> So assuming it is the sender and I can find one, any tips on dropping
>> the tank. Also is there any way to tell the difference between the 14.5
>> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
>> let it get very low, so I am not sure.
>>
>> Aloha from Maui
>> Joe
>
>
05-03-2006, 01:32 AM
#9
Guest
Posts: n/a
Re: Fuel Guage not working
Thanks Earl
Since I have the carb 4.2 L with the mechanical pump, I sure don't need
the in the tank pump used on the FI model. Hard to believe that price
isn't for the combined pump/sender unit as you said. Thanks again for
the ideas.
Earle Horton wrote:
> The sender unit consists of a float attached to a moveable arm, that moves a
> variable resistor. The electrical resistance at the sender unit terminals
> will change as the arm is moved. I can tell you right now, that the Haynes
> Automotive Repair Manual that I have, part number 50030 (1777), for the 1987
> through 1995 Jeep Wrangler, does not contain the resistance values, that you
> need to test the sender unit. :o( A cursory scan of that section of the
> manual indicates, that it may be useful for removing the tank. I suggest
> removing the tank, to inspect the sender unit. :o(
>
> The sender unit is tested electrically, by moving the arm with a DVOM (Drive
> Vehicle Off Mountain or Digital Volt Ohm Meter, I can't remember which)
> attached to the sender unit terminals. The resistance should change
> smoothly as the arm is moved. Lacking the specifications, I can't tell you
> more. If the float is saturated or full of fuel, it will feel heavy or make
> a sloshing sound.
>
> Other suspects are a faulty electrical connection at the fuel pump/sender
> unit connector, a fault in the wiring to the sender unit, and a bad gauge.
> If you can identify and access the wires to the sender unit (Haynes wiring
> diagrams are pretty bad too) then you can check for voltage to the sender
> unit with the key on. We used to short the terminal to ground, and watch
> the gauge go to full, on some older vehicles, but I do not know whether this
> is recommended for your vehicle. The Haynes manual is short on
> troubleshooting tips in this area.
>
> It does sound as if the price quoted, is for a sender/fuel pump unit. They
> appear to be a single unit. On vehicles with a 20 gallon tank, the fuel
> pump/sender unit is mounted with eight screws. The fifteen gallon tank has
> a lock ring. The Haynes manual says "if the ring is difficult to remove,
> tap it loose with a wood dowel or brass punch and a small mallet (DO NOT use
> a steel punch, or you could cause an explosion!)" They show a steel
> screwdriver being used.
>
> The behavior of your gauge is consistent with a flooded float, but not a
> 100% indication. On my old Plymouth Valiant, this was a fifteen minute job,
> if the tank was below one quarter full. Things sure have changed. My
> advice is to get some penetrating oil on the tank mounting bolts, a couple
> of days before you try dropping the tank.
>
> Earle
>
> "Joe and Joann" <mauijoeb@removehawaii.rr.com> wrote in message
> news:EKV5g.11377$MP2.1636@tornado.socal.rr.com...
>> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
>> stopped working. It always reads zero or almost zero.The rest of the
>> guages working OK. My guess is the sending unit. Any other likely
>> possibilities. The dealer wanted nearly $250 for A new sender (not
>> including installation) This seems a bit high to me, more like the price
>> for the FI unit that includes the pump. Is there anyway to isolate the
>> problem to the guage itself rather than the sender. If it is important,
>> the guage does move slightly to the right when the power is turned on,
>> but only gets to empty.
>>
>> So assuming it is the sender and I can find one, any tips on dropping
>> the tank. Also is there any way to tell the difference between the 14.5
>> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
>> let it get very low, so I am not sure.
>>
>> Aloha from Maui
>> Joe
>
>
Since I have the carb 4.2 L with the mechanical pump, I sure don't need
the in the tank pump used on the FI model. Hard to believe that price
isn't for the combined pump/sender unit as you said. Thanks again for
the ideas.
Earle Horton wrote:
> The sender unit consists of a float attached to a moveable arm, that moves a
> variable resistor. The electrical resistance at the sender unit terminals
> will change as the arm is moved. I can tell you right now, that the Haynes
> Automotive Repair Manual that I have, part number 50030 (1777), for the 1987
> through 1995 Jeep Wrangler, does not contain the resistance values, that you
> need to test the sender unit. :o( A cursory scan of that section of the
> manual indicates, that it may be useful for removing the tank. I suggest
> removing the tank, to inspect the sender unit. :o(
>
> The sender unit is tested electrically, by moving the arm with a DVOM (Drive
> Vehicle Off Mountain or Digital Volt Ohm Meter, I can't remember which)
> attached to the sender unit terminals. The resistance should change
> smoothly as the arm is moved. Lacking the specifications, I can't tell you
> more. If the float is saturated or full of fuel, it will feel heavy or make
> a sloshing sound.
>
> Other suspects are a faulty electrical connection at the fuel pump/sender
> unit connector, a fault in the wiring to the sender unit, and a bad gauge.
> If you can identify and access the wires to the sender unit (Haynes wiring
> diagrams are pretty bad too) then you can check for voltage to the sender
> unit with the key on. We used to short the terminal to ground, and watch
> the gauge go to full, on some older vehicles, but I do not know whether this
> is recommended for your vehicle. The Haynes manual is short on
> troubleshooting tips in this area.
>
> It does sound as if the price quoted, is for a sender/fuel pump unit. They
> appear to be a single unit. On vehicles with a 20 gallon tank, the fuel
> pump/sender unit is mounted with eight screws. The fifteen gallon tank has
> a lock ring. The Haynes manual says "if the ring is difficult to remove,
> tap it loose with a wood dowel or brass punch and a small mallet (DO NOT use
> a steel punch, or you could cause an explosion!)" They show a steel
> screwdriver being used.
>
> The behavior of your gauge is consistent with a flooded float, but not a
> 100% indication. On my old Plymouth Valiant, this was a fifteen minute job,
> if the tank was below one quarter full. Things sure have changed. My
> advice is to get some penetrating oil on the tank mounting bolts, a couple
> of days before you try dropping the tank.
>
> Earle
>
> "Joe and Joann" <mauijoeb@removehawaii.rr.com> wrote in message
> news:EKV5g.11377$MP2.1636@tornado.socal.rr.com...
>> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
>> stopped working. It always reads zero or almost zero.The rest of the
>> guages working OK. My guess is the sending unit. Any other likely
>> possibilities. The dealer wanted nearly $250 for A new sender (not
>> including installation) This seems a bit high to me, more like the price
>> for the FI unit that includes the pump. Is there anyway to isolate the
>> problem to the guage itself rather than the sender. If it is important,
>> the guage does move slightly to the right when the power is turned on,
>> but only gets to empty.
>>
>> So assuming it is the sender and I can find one, any tips on dropping
>> the tank. Also is there any way to tell the difference between the 14.5
>> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
>> let it get very low, so I am not sure.
>>
>> Aloha from Maui
>> Joe
>
>
05-03-2006, 01:32 AM
#10
Guest
Posts: n/a
Re: Fuel Guage not working
Thanks Earl
Since I have the carb 4.2 L with the mechanical pump, I sure don't need
the in the tank pump used on the FI model. Hard to believe that price
isn't for the combined pump/sender unit as you said. Thanks again for
the ideas.
Earle Horton wrote:
> The sender unit consists of a float attached to a moveable arm, that moves a
> variable resistor. The electrical resistance at the sender unit terminals
> will change as the arm is moved. I can tell you right now, that the Haynes
> Automotive Repair Manual that I have, part number 50030 (1777), for the 1987
> through 1995 Jeep Wrangler, does not contain the resistance values, that you
> need to test the sender unit. :o( A cursory scan of that section of the
> manual indicates, that it may be useful for removing the tank. I suggest
> removing the tank, to inspect the sender unit. :o(
>
> The sender unit is tested electrically, by moving the arm with a DVOM (Drive
> Vehicle Off Mountain or Digital Volt Ohm Meter, I can't remember which)
> attached to the sender unit terminals. The resistance should change
> smoothly as the arm is moved. Lacking the specifications, I can't tell you
> more. If the float is saturated or full of fuel, it will feel heavy or make
> a sloshing sound.
>
> Other suspects are a faulty electrical connection at the fuel pump/sender
> unit connector, a fault in the wiring to the sender unit, and a bad gauge.
> If you can identify and access the wires to the sender unit (Haynes wiring
> diagrams are pretty bad too) then you can check for voltage to the sender
> unit with the key on. We used to short the terminal to ground, and watch
> the gauge go to full, on some older vehicles, but I do not know whether this
> is recommended for your vehicle. The Haynes manual is short on
> troubleshooting tips in this area.
>
> It does sound as if the price quoted, is for a sender/fuel pump unit. They
> appear to be a single unit. On vehicles with a 20 gallon tank, the fuel
> pump/sender unit is mounted with eight screws. The fifteen gallon tank has
> a lock ring. The Haynes manual says "if the ring is difficult to remove,
> tap it loose with a wood dowel or brass punch and a small mallet (DO NOT use
> a steel punch, or you could cause an explosion!)" They show a steel
> screwdriver being used.
>
> The behavior of your gauge is consistent with a flooded float, but not a
> 100% indication. On my old Plymouth Valiant, this was a fifteen minute job,
> if the tank was below one quarter full. Things sure have changed. My
> advice is to get some penetrating oil on the tank mounting bolts, a couple
> of days before you try dropping the tank.
>
> Earle
>
> "Joe and Joann" <mauijoeb@removehawaii.rr.com> wrote in message
> news:EKV5g.11377$MP2.1636@tornado.socal.rr.com...
>> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
>> stopped working. It always reads zero or almost zero.The rest of the
>> guages working OK. My guess is the sending unit. Any other likely
>> possibilities. The dealer wanted nearly $250 for A new sender (not
>> including installation) This seems a bit high to me, more like the price
>> for the FI unit that includes the pump. Is there anyway to isolate the
>> problem to the guage itself rather than the sender. If it is important,
>> the guage does move slightly to the right when the power is turned on,
>> but only gets to empty.
>>
>> So assuming it is the sender and I can find one, any tips on dropping
>> the tank. Also is there any way to tell the difference between the 14.5
>> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
>> let it get very low, so I am not sure.
>>
>> Aloha from Maui
>> Joe
>
>
Since I have the carb 4.2 L with the mechanical pump, I sure don't need
the in the tank pump used on the FI model. Hard to believe that price
isn't for the combined pump/sender unit as you said. Thanks again for
the ideas.
Earle Horton wrote:
> The sender unit consists of a float attached to a moveable arm, that moves a
> variable resistor. The electrical resistance at the sender unit terminals
> will change as the arm is moved. I can tell you right now, that the Haynes
> Automotive Repair Manual that I have, part number 50030 (1777), for the 1987
> through 1995 Jeep Wrangler, does not contain the resistance values, that you
> need to test the sender unit. :o( A cursory scan of that section of the
> manual indicates, that it may be useful for removing the tank. I suggest
> removing the tank, to inspect the sender unit. :o(
>
> The sender unit is tested electrically, by moving the arm with a DVOM (Drive
> Vehicle Off Mountain or Digital Volt Ohm Meter, I can't remember which)
> attached to the sender unit terminals. The resistance should change
> smoothly as the arm is moved. Lacking the specifications, I can't tell you
> more. If the float is saturated or full of fuel, it will feel heavy or make
> a sloshing sound.
>
> Other suspects are a faulty electrical connection at the fuel pump/sender
> unit connector, a fault in the wiring to the sender unit, and a bad gauge.
> If you can identify and access the wires to the sender unit (Haynes wiring
> diagrams are pretty bad too) then you can check for voltage to the sender
> unit with the key on. We used to short the terminal to ground, and watch
> the gauge go to full, on some older vehicles, but I do not know whether this
> is recommended for your vehicle. The Haynes manual is short on
> troubleshooting tips in this area.
>
> It does sound as if the price quoted, is for a sender/fuel pump unit. They
> appear to be a single unit. On vehicles with a 20 gallon tank, the fuel
> pump/sender unit is mounted with eight screws. The fifteen gallon tank has
> a lock ring. The Haynes manual says "if the ring is difficult to remove,
> tap it loose with a wood dowel or brass punch and a small mallet (DO NOT use
> a steel punch, or you could cause an explosion!)" They show a steel
> screwdriver being used.
>
> The behavior of your gauge is consistent with a flooded float, but not a
> 100% indication. On my old Plymouth Valiant, this was a fifteen minute job,
> if the tank was below one quarter full. Things sure have changed. My
> advice is to get some penetrating oil on the tank mounting bolts, a couple
> of days before you try dropping the tank.
>
> Earle
>
> "Joe and Joann" <mauijoeb@removehawaii.rr.com> wrote in message
> news:EKV5g.11377$MP2.1636@tornado.socal.rr.com...
>> I have a 90 YJ Sahara 4.2 L with about 70K miles. The fuel guage just
>> stopped working. It always reads zero or almost zero.The rest of the
>> guages working OK. My guess is the sending unit. Any other likely
>> possibilities. The dealer wanted nearly $250 for A new sender (not
>> including installation) This seems a bit high to me, more like the price
>> for the FI unit that includes the pump. Is there anyway to isolate the
>> problem to the guage itself rather than the sender. If it is important,
>> the guage does move slightly to the right when the power is turned on,
>> but only gets to empty.
>>
>> So assuming it is the sender and I can find one, any tips on dropping
>> the tank. Also is there any way to tell the difference between the 14.5
>> gallon tank and the 20. Pretty sure I have the smaller tank, but I never
>> let it get very low, so I am not sure.
>>
>> Aloha from Maui
>> Joe
>
>