I am getting some strange readings from my fuel, oil pressure, and
temperature gauges on my 1977 Cherokee Chief as follows;

When I simply turn on the ignition but don'g start the engine, all
three read accurately and stay at those readings. The ammeter, of
course, operates independently of these three, and functions normally
under all conditions.

When I start the engine, they all read accurately at first, then
slowly drop to the lower readings. For example, the fuel gauge drops
almost a quarter of a tank, and the other two drop likewise. At some
point, they may return to normal for a while, especially in cooler
parts of the day (or when cooled by the AC). It makes no difference
if accessories such as the AC are operating.

If I kill the engine, then turn the ignition right back on (or wait a
while- it doesn't matter), they all three return to normal readings
and stay there, regardless of temperature.

Any ideas, anyone? This is something I haven't seen before! Thanks!

Dan

 

"Hootowl" <ELN/zooo@earthlink.net> wrote in message
news:qtpfg1h75a61c4pef9ep06nhkiesmd9kjm@4ax.com...
> I am getting some strange readings from my fuel, oil pressure, and
> temperature gauges on my 1977 Cherokee Chief as follows;
>
> When I simply turn on the ignition but don'g start the engine, all
> three read accurately and stay at those readings. The ammeter, of
> course, operates independently of these three, and functions normally
> under all conditions.
>
> When I start the engine, they all read accurately at first, then
> slowly drop to the lower readings. For example, the fuel gauge drops
> almost a quarter of a tank, and the other two drop likewise. At some
> point, they may return to normal for a while, especially in cooler
> parts of the day (or when cooled by the AC). It makes no difference
> if accessories such as the AC are operating.
>
> If I kill the engine, then turn the ignition right back on (or wait a
> while- it doesn't matter), they all three return to normal readings
> and stay there, regardless of temperature.
>
> Any ideas, anyone? This is something I haven't seen before! Thanks!

The regulator is stuck open... believe it or not, there's
a bimetallic strip that opens/closes faster or slower,
depending on the ambient temperature... the voltage
looks like it's going crazy, but it's average is regulated
over time. Either the contact is dirty, or something
else is preventing it from shorting itself and cooling
down, hence your lowered reference voltage to your
instruments when the temp is high.
__
Steve
..

 

"Hootowl" <ELN/zooo@earthlink.net> wrote in message
news:qtpfg1h75a61c4pef9ep06nhkiesmd9kjm@4ax.com...
> I am getting some strange readings from my fuel, oil pressure, and
> temperature gauges on my 1977 Cherokee Chief as follows;
>
> When I simply turn on the ignition but don'g start the engine, all
> three read accurately and stay at those readings. The ammeter, of
> course, operates independently of these three, and functions normally
> under all conditions.
>
> When I start the engine, they all read accurately at first, then
> slowly drop to the lower readings. For example, the fuel gauge drops
> almost a quarter of a tank, and the other two drop likewise. At some
> point, they may return to normal for a while, especially in cooler
> parts of the day (or when cooled by the AC). It makes no difference
> if accessories such as the AC are operating.
>
> If I kill the engine, then turn the ignition right back on (or wait a
> while- it doesn't matter), they all three return to normal readings
> and stay there, regardless of temperature.
>
> Any ideas, anyone? This is something I haven't seen before! Thanks!

The regulator is stuck open... believe it or not, there's
a bimetallic strip that opens/closes faster or slower,
depending on the ambient temperature... the voltage
looks like it's going crazy, but it's average is regulated
over time. Either the contact is dirty, or something
else is preventing it from shorting itself and cooling
down, hence your lowered reference voltage to your
instruments when the temp is high.
__
Steve
..

 

"Hootowl" <ELN/zooo@earthlink.net> wrote in message
news:qtpfg1h75a61c4pef9ep06nhkiesmd9kjm@4ax.com...
> I am getting some strange readings from my fuel, oil pressure, and
> temperature gauges on my 1977 Cherokee Chief as follows;
>
> When I simply turn on the ignition but don'g start the engine, all
> three read accurately and stay at those readings. The ammeter, of
> course, operates independently of these three, and functions normally
> under all conditions.
>
> When I start the engine, they all read accurately at first, then
> slowly drop to the lower readings. For example, the fuel gauge drops
> almost a quarter of a tank, and the other two drop likewise. At some
> point, they may return to normal for a while, especially in cooler
> parts of the day (or when cooled by the AC). It makes no difference
> if accessories such as the AC are operating.
>
> If I kill the engine, then turn the ignition right back on (or wait a
> while- it doesn't matter), they all three return to normal readings
> and stay there, regardless of temperature.
>
> Any ideas, anyone? This is something I haven't seen before! Thanks!

The regulator is stuck open... believe it or not, there's
a bimetallic strip that opens/closes faster or slower,
depending on the ambient temperature... the voltage
looks like it's going crazy, but it's average is regulated
over time. Either the contact is dirty, or something
else is preventing it from shorting itself and cooling
down, hence your lowered reference voltage to your
instruments when the temp is high.
__
Steve
..

 

"Hootowl" <ELN/zooo@earthlink.net> wrote in message
news:qtpfg1h75a61c4pef9ep06nhkiesmd9kjm@4ax.com...
> I am getting some strange readings from my fuel, oil pressure, and
> temperature gauges on my 1977 Cherokee Chief as follows;
>
> When I simply turn on the ignition but don'g start the engine, all
> three read accurately and stay at those readings. The ammeter, of
> course, operates independently of these three, and functions normally
> under all conditions.
>
> When I start the engine, they all read accurately at first, then
> slowly drop to the lower readings. For example, the fuel gauge drops
> almost a quarter of a tank, and the other two drop likewise. At some
> point, they may return to normal for a while, especially in cooler
> parts of the day (or when cooled by the AC). It makes no difference
> if accessories such as the AC are operating.
>
> If I kill the engine, then turn the ignition right back on (or wait a
> while- it doesn't matter), they all three return to normal readings
> and stay there, regardless of temperature.
>
> Any ideas, anyone? This is something I haven't seen before! Thanks!

The regulator is stuck open... believe it or not, there's
a bimetallic strip that opens/closes faster or slower,
depending on the ambient temperature... the voltage
looks like it's going crazy, but it's average is regulated
over time. Either the contact is dirty, or something
else is preventing it from shorting itself and cooling
down, hence your lowered reference voltage to your
instruments when the temp is high.
__
Steve
..

 

On Tue, 23 Aug 2005 01:13:53 GMT, "Stephen Cowell"
<scowell@sbcglobal.net> wrote:

>
>"Hootowl" <ELN/zooo@earthlink.net> wrote in message
>news:qtpfg1h75a61c4pef9ep06nhkiesmd9kjm@4ax.com.. .
>> I am getting some strange readings from my fuel, oil pressure, and
>> temperature gauges on my 1977 Cherokee Chief as follows;
>>
>> When I simply turn on the ignition but don'g start the engine, all
>> three read accurately and stay at those readings. The ammeter, of
>> course, operates independently of these three, and functions normally
>> under all conditions.
>>
>> When I start the engine, they all read accurately at first, then
>> slowly drop to the lower readings. For example, the fuel gauge drops
>> almost a quarter of a tank, and the other two drop likewise. At some
>> point, they may return to normal for a while, especially in cooler
>> parts of the day (or when cooled by the AC). It makes no difference
>> if accessories such as the AC are operating.
>>
>> If I kill the engine, then turn the ignition right back on (or wait a
>> while- it doesn't matter), they all three return to normal readings
>> and stay there, regardless of temperature.
>>
>> Any ideas, anyone? This is something I haven't seen before! Thanks!
>
>The regulator is stuck open... believe it or not, there's
>a bimetallic strip that opens/closes faster or slower,
>depending on the ambient temperature... the voltage
>looks like it's going crazy, but it's average is regulated
>over time. Either the contact is dirty, or something
>else is preventing it from shorting itself and cooling
>down, hence your lowered reference voltage to your
>instruments when the temp is high.

Steve,

Are you talking about the cluster voltage regulator (CVR) that fits
down on two posts beside the temperature gauge? Doesn't it provide a
constant 3.2 volts to the cluster gauges? If so, it is no longer
available. The dealer (whom I know personally) can't get it anymore.
NAPA no longer handles them for any make. Another local parts house
does, but not for Jeep. The two or three they do carry looked like
they might fit, if all gauges use the same voltage. A Jeep mechanic I
know said I've lost the ground to the dash. Someone in another Jeep
news group also thinks it's a ground problem. Anyway, my friend is
going to be checking out a rear joint for me later this morning (I
have no safe place to raise two wheels), and he can look at the gauge
problem, too, if it doesn't get too hot for him. He has heart
problems and a previous stroke.

That CVR would be a salvage yard item now, and I figure they would
want to sell me the entire circuit board and cluster.

Dan
>__
>Steve
>.
>

 

On Tue, 23 Aug 2005 01:13:53 GMT, "Stephen Cowell"
<scowell@sbcglobal.net> wrote:

>
>"Hootowl" <ELN/zooo@earthlink.net> wrote in message
>news:qtpfg1h75a61c4pef9ep06nhkiesmd9kjm@4ax.com.. .
>> I am getting some strange readings from my fuel, oil pressure, and
>> temperature gauges on my 1977 Cherokee Chief as follows;
>>
>> When I simply turn on the ignition but don'g start the engine, all
>> three read accurately and stay at those readings. The ammeter, of
>> course, operates independently of these three, and functions normally
>> under all conditions.
>>
>> When I start the engine, they all read accurately at first, then
>> slowly drop to the lower readings. For example, the fuel gauge drops
>> almost a quarter of a tank, and the other two drop likewise. At some
>> point, they may return to normal for a while, especially in cooler
>> parts of the day (or when cooled by the AC). It makes no difference
>> if accessories such as the AC are operating.
>>
>> If I kill the engine, then turn the ignition right back on (or wait a
>> while- it doesn't matter), they all three return to normal readings
>> and stay there, regardless of temperature.
>>
>> Any ideas, anyone? This is something I haven't seen before! Thanks!
>
>The regulator is stuck open... believe it or not, there's
>a bimetallic strip that opens/closes faster or slower,
>depending on the ambient temperature... the voltage
>looks like it's going crazy, but it's average is regulated
>over time. Either the contact is dirty, or something
>else is preventing it from shorting itself and cooling
>down, hence your lowered reference voltage to your
>instruments when the temp is high.

Steve,

Are you talking about the cluster voltage regulator (CVR) that fits
down on two posts beside the temperature gauge? Doesn't it provide a
constant 3.2 volts to the cluster gauges? If so, it is no longer
available. The dealer (whom I know personally) can't get it anymore.
NAPA no longer handles them for any make. Another local parts house
does, but not for Jeep. The two or three they do carry looked like
they might fit, if all gauges use the same voltage. A Jeep mechanic I
know said I've lost the ground to the dash. Someone in another Jeep
news group also thinks it's a ground problem. Anyway, my friend is
going to be checking out a rear joint for me later this morning (I
have no safe place to raise two wheels), and he can look at the gauge
problem, too, if it doesn't get too hot for him. He has heart
problems and a previous stroke.

That CVR would be a salvage yard item now, and I figure they would
want to sell me the entire circuit board and cluster.

Dan
>__
>Steve
>.
>

 

On Tue, 23 Aug 2005 01:13:53 GMT, "Stephen Cowell"
<scowell@sbcglobal.net> wrote:

>
>"Hootowl" <ELN/zooo@earthlink.net> wrote in message
>news:qtpfg1h75a61c4pef9ep06nhkiesmd9kjm@4ax.com.. .
>> I am getting some strange readings from my fuel, oil pressure, and
>> temperature gauges on my 1977 Cherokee Chief as follows;
>>
>> When I simply turn on the ignition but don'g start the engine, all
>> three read accurately and stay at those readings. The ammeter, of
>> course, operates independently of these three, and functions normally
>> under all conditions.
>>
>> When I start the engine, they all read accurately at first, then
>> slowly drop to the lower readings. For example, the fuel gauge drops
>> almost a quarter of a tank, and the other two drop likewise. At some
>> point, they may return to normal for a while, especially in cooler
>> parts of the day (or when cooled by the AC). It makes no difference
>> if accessories such as the AC are operating.
>>
>> If I kill the engine, then turn the ignition right back on (or wait a
>> while- it doesn't matter), they all three return to normal readings
>> and stay there, regardless of temperature.
>>
>> Any ideas, anyone? This is something I haven't seen before! Thanks!
>
>The regulator is stuck open... believe it or not, there's
>a bimetallic strip that opens/closes faster or slower,
>depending on the ambient temperature... the voltage
>looks like it's going crazy, but it's average is regulated
>over time. Either the contact is dirty, or something
>else is preventing it from shorting itself and cooling
>down, hence your lowered reference voltage to your
>instruments when the temp is high.

Steve,

Are you talking about the cluster voltage regulator (CVR) that fits
down on two posts beside the temperature gauge? Doesn't it provide a
constant 3.2 volts to the cluster gauges? If so, it is no longer
available. The dealer (whom I know personally) can't get it anymore.
NAPA no longer handles them for any make. Another local parts house
does, but not for Jeep. The two or three they do carry looked like
they might fit, if all gauges use the same voltage. A Jeep mechanic I
know said I've lost the ground to the dash. Someone in another Jeep
news group also thinks it's a ground problem. Anyway, my friend is
going to be checking out a rear joint for me later this morning (I
have no safe place to raise two wheels), and he can look at the gauge
problem, too, if it doesn't get too hot for him. He has heart
problems and a previous stroke.

That CVR would be a salvage yard item now, and I figure they would
want to sell me the entire circuit board and cluster.

Dan
>__
>Steve
>.
>

 

On Tue, 23 Aug 2005 01:13:53 GMT, "Stephen Cowell"
<scowell@sbcglobal.net> wrote:

>
>"Hootowl" <ELN/zooo@earthlink.net> wrote in message
>news:qtpfg1h75a61c4pef9ep06nhkiesmd9kjm@4ax.com.. .
>> I am getting some strange readings from my fuel, oil pressure, and
>> temperature gauges on my 1977 Cherokee Chief as follows;
>>
>> When I simply turn on the ignition but don'g start the engine, all
>> three read accurately and stay at those readings. The ammeter, of
>> course, operates independently of these three, and functions normally
>> under all conditions.
>>
>> When I start the engine, they all read accurately at first, then
>> slowly drop to the lower readings. For example, the fuel gauge drops
>> almost a quarter of a tank, and the other two drop likewise. At some
>> point, they may return to normal for a while, especially in cooler
>> parts of the day (or when cooled by the AC). It makes no difference
>> if accessories such as the AC are operating.
>>
>> If I kill the engine, then turn the ignition right back on (or wait a
>> while- it doesn't matter), they all three return to normal readings
>> and stay there, regardless of temperature.
>>
>> Any ideas, anyone? This is something I haven't seen before! Thanks!
>
>The regulator is stuck open... believe it or not, there's
>a bimetallic strip that opens/closes faster or slower,
>depending on the ambient temperature... the voltage
>looks like it's going crazy, but it's average is regulated
>over time. Either the contact is dirty, or something
>else is preventing it from shorting itself and cooling
>down, hence your lowered reference voltage to your
>instruments when the temp is high.

Steve,

Are you talking about the cluster voltage regulator (CVR) that fits
down on two posts beside the temperature gauge? Doesn't it provide a
constant 3.2 volts to the cluster gauges? If so, it is no longer
available. The dealer (whom I know personally) can't get it anymore.
NAPA no longer handles them for any make. Another local parts house
does, but not for Jeep. The two or three they do carry looked like
they might fit, if all gauges use the same voltage. A Jeep mechanic I
know said I've lost the ground to the dash. Someone in another Jeep
news group also thinks it's a ground problem. Anyway, my friend is
going to be checking out a rear joint for me later this morning (I
have no safe place to raise two wheels), and he can look at the gauge
problem, too, if it doesn't get too hot for him. He has heart
problems and a previous stroke.

That CVR would be a salvage yard item now, and I figure they would
want to sell me the entire circuit board and cluster.

Dan
>__
>Steve
>.
>

 

It's a good thing for you, it's not a Chrysler product of the same vintage.
If you lost the ground to the dash on one of those, you would fry your fuel
gauge. Ouch!

Before you do anything, try fixing the instrument panel ground. I have a
policy with vehicles, of addressing the easiest to fix problem first. It is
amazing how often this works.

If it turns out to be the regulator, and there is no replacement available,
one is easily made with parts available from your local Radio Shack. Radio
Shack has the books you will need, too. Before you get that far, perform a
proper diagnosis using a voltmeter. It is essential to have the proper
manual for your vehicle. Many public libraries have old Motors Manuals
still on the shelves. These are the best, next to the factory service
manual. Chilton's is not too bad. Haynes is economical.

Earle

"Hootowl" <ELN/zooo@earthlink.net> wrote in message
news:4oglg1t8ifm7jov40t1s4in470t0mp7n19@4ax.com...
> On Tue, 23 Aug 2005 01:13:53 GMT, "Stephen Cowell"
> <scowell@sbcglobal.net> wrote:
>
> >
> >"Hootowl" <ELN/zooo@earthlink.net> wrote in message
> >news:qtpfg1h75a61c4pef9ep06nhkiesmd9kjm@4ax.com.. .
> >> I am getting some strange readings from my fuel, oil pressure, and
> >> temperature gauges on my 1977 Cherokee Chief as follows;
> >>
> >> When I simply turn on the ignition but don'g start the engine, all
> >> three read accurately and stay at those readings. The ammeter, of
> >> course, operates independently of these three, and functions normally
> >> under all conditions.
> >>
> >> When I start the engine, they all read accurately at first, then
> >> slowly drop to the lower readings. For example, the fuel gauge drops
> >> almost a quarter of a tank, and the other two drop likewise. At some
> >> point, they may return to normal for a while, especially in cooler
> >> parts of the day (or when cooled by the AC). It makes no difference
> >> if accessories such as the AC are operating.
> >>
> >> If I kill the engine, then turn the ignition right back on (or wait a
> >> while- it doesn't matter), they all three return to normal readings
> >> and stay there, regardless of temperature.
> >>
> >> Any ideas, anyone? This is something I haven't seen before! Thanks!
> >
> >The regulator is stuck open... believe it or not, there's
> >a bimetallic strip that opens/closes faster or slower,
> >depending on the ambient temperature... the voltage
> >looks like it's going crazy, but it's average is regulated
> >over time. Either the contact is dirty, or something
> >else is preventing it from shorting itself and cooling
> >down, hence your lowered reference voltage to your
> >instruments when the temp is high.
>
> Steve,
>
> Are you talking about the cluster voltage regulator (CVR) that fits
> down on two posts beside the temperature gauge? Doesn't it provide a
> constant 3.2 volts to the cluster gauges? If so, it is no longer
> available. The dealer (whom I know personally) can't get it anymore.
> NAPA no longer handles them for any make. Another local parts house
> does, but not for Jeep. The two or three they do carry looked like
> they might fit, if all gauges use the same voltage. A Jeep mechanic I
> know said I've lost the ground to the dash. Someone in another Jeep
> news group also thinks it's a ground problem. Anyway, my friend is
> going to be checking out a rear joint for me later this morning (I
> have no safe place to raise two wheels), and he can look at the gauge
> problem, too, if it doesn't get too hot for him. He has heart
> problems and a previous stroke.
>
> That CVR would be a salvage yard item now, and I figure they would
> want to sell me the entire circuit board and cluster.
>
> Dan
> >__
> >Steve
> >.
> >
>