חיבור מד דלק - שירשור ישן בנושא

[Bulldog]

חיפשתי ולא מצאתי.
יש הדקים
I
A
S
מי הולך לאן? או יותר נכון מה מתחבר לאן? גם העברה לשירשור ישן תתקבל בברכה.
עומר

[עירא]

Fuel Gauge S Terminal - pink wire (from fuel sender)
Fuel Gauge A Terminal - 12v side of Jumper/Regulator Strip to temperature gauge
Fuel Gauge I Terminal - red wire (ignition-on hot 12v)

[עירא]

והנה כל העסק:

From the passenger side which is left to right in the picture above.


Fuel Gauge S Terminal - pink wire (from fuel sender)
Fuel Gauge A Terminal - 12v side of Jumper/Regulator Strip to temperature gauge
Fuel Gauge I Terminal - red wire (ignition-on hot 12v)
Temperature Gauge A Terminal - Jumper from fuel gauge A terminal (Jumper Strap regulated to 5v)
Temperature Gauge S Terminal - Purple wire (from temperature sender)
Some manuals have the positions of these terminals incorrectly identified. You can see the letters stamped in the insulation material around the posts.

The Jumper/Regulator Strap is composed of two strips of metal that continuously make and break contact, regulating the output to the Temp gauge to 5 volts. A volt meter applied to the A terminal on the Temp gauge should fluctuate (plus and minus) near 5 volts. A reading of 12 volts on the temperature side indicates a bad Jumper/Regulator Strap. 12 volts applied to the temperature gauge's A terminal will cook the gauge.

Fuel Gauge
The fuel gauge should have the following resistances ...


S to Ground 68-72 ohms
S to I 19-21 ohms
S to A 19-21 ohms
I to A Zero
I to Ground 49-51 ohms
A to Ground 49-51 ohms

The fuel sending unit wires are located on top of the gas tank where they are hard to get to without dropping the tank. The fuel sending unit should have a pink wire with voltage on the isolated center post. The other black wire on the sending unit with a tab style connector is a ground to the frame. Make sure it has good contact.

To be sure the problem is not the gauge, you can momentarily short the pink wire on the output of the sender to ground, and this should show up as FULL on your gauge. DO NOT hold it for very long in this position. If the gauge does not move from EMPTY either the wiring has an open circuit (no voltage, or no connection to ground) or he gauge is bad. If it does move, the sending unit is bad.

The sending unit can be checked with an ohmmeter to measure the resistance between the round sender post (pink wire) and ground. It should be:

Resistance Reading
73 ohms Empty
23 ohms 1/2 tank
10 ohms Full


If the resistance falls in this ballpark (depending on how much gas you have in the tank), then the sending unit is fine. If it shows infinitely HIGH resistance, then the sending unit could be bad OR the wire from the tank to the gauge could be open.

The gauge can be tested with the resistances listed above. Run an appropriate resistor to the S terminal of the fuel gauge and to ground and check the readings.

Temperature Gauge
The temp gauge has the following resistance ...


S to A 19-21 ohms

A volt meter can be used to measure the voltage between the A terminal of the Temp gauge and ground. It should be pulsing and averaging about 5 volts. If it reads 12 volts the Jumper Strip/Regulator is bad. If it reads 0 volts, it has been burnt out.

The sending unit can be checked with the following resistances between the post and ground...

Totally Cold high resistance
Slightly Warm 73 ohms
Beginning of Band 36 ohms
End of Band 13 ohms
Hot 9 ohms

[AvigdorAharon]

עירא,
הבחור שאל על מד הדלק ואתה העתקת את כל הספר...
:wink:

אביגדור

[Bulldog]

עירא, הראשון הספיק, תודה.

[tzagi]

Ira, dont pay attention to them
overkill is just right
everytime!
If something is worth doing then its worth doing right

Good work

Omer , good luck with making it work right
I havnt seen a cj fuel gage that worked right for years
make sure to ground the sending unit properly
if in dought, use 2 ground straps
That seems to be a major problem with older frames as the ground connections rust