gatorman21218
Registered User
I know yall know that the factory oil gauge is just an idiot light but here is a service bulliten from carquest in 1999. Kinda cool
http://www.carquest.com/common/downloads/partsTechEngineTt4q99.cq.pdf
1987-88 FORD TRUCKS F
SERIES, BRONCO W/ 4.9,
5.0, 5.8, & 7.3 L ENGINESLOW
OR ERRATIC OIL
PRESSURE GAUGE
READINGS
If you run across one of these vehicles
that is equipped with a gauge which reads
low or erratic oil pressure, here is
something to keep in mind. These vehicles
do not really have what we would call a
conventional oil pressure gauge. The
sending unit that is used is not a variable
resistance unit. It is merely an “On-Off”
switch. There is a fixed resistance in the
dash gauge that will cause the needle to
deflect a certain amount regardless of the
actual oil pressure. So, it does not matter
how high or low the pressure, in any case,
the gauge will read the same, as long as
there is sufficient oil pressure to close the
switch. Any time there is a question of oil
pressure, the first step is to ignore what
the gauge reads and verify the oil pressure
with a mechanical gauge. Once you have
eliminated a mechanical problem, then
concentrate on the electrical part. On these
vehicles, if you have eliminated the
mechanical problem, and, have replaced
the oil pressure sender with no
improvement in the gauge reading, Ford
recommends that you use a 20 ohm
resistor in line between the sending unit
and the gauge. Installation of the resistor
will stabilize the gauge reading and
eliminate the customer concern.
Bob Reuther- Technical Services
http://www.carquest.com/common/downloads/partsTechEngineTt4q99.cq.pdf
1987-88 FORD TRUCKS F
SERIES, BRONCO W/ 4.9,
5.0, 5.8, & 7.3 L ENGINESLOW
OR ERRATIC OIL
PRESSURE GAUGE
READINGS
If you run across one of these vehicles
that is equipped with a gauge which reads
low or erratic oil pressure, here is
something to keep in mind. These vehicles
do not really have what we would call a
conventional oil pressure gauge. The
sending unit that is used is not a variable
resistance unit. It is merely an “On-Off”
switch. There is a fixed resistance in the
dash gauge that will cause the needle to
deflect a certain amount regardless of the
actual oil pressure. So, it does not matter
how high or low the pressure, in any case,
the gauge will read the same, as long as
there is sufficient oil pressure to close the
switch. Any time there is a question of oil
pressure, the first step is to ignore what
the gauge reads and verify the oil pressure
with a mechanical gauge. Once you have
eliminated a mechanical problem, then
concentrate on the electrical part. On these
vehicles, if you have eliminated the
mechanical problem, and, have replaced
the oil pressure sender with no
improvement in the gauge reading, Ford
recommends that you use a 20 ohm
resistor in line between the sending unit
and the gauge. Installation of the resistor
will stabilize the gauge reading and
eliminate the customer concern.
Bob Reuther- Technical Services
