Avoiding cavitation issues with an external fuel pump is a must when you want to reach the finish line. We have included a couple steps below that will help mitigate the chances of external fuel pump cavitation from occurring. 

1. If possible, make sure that the external fuel pump is installed in a location that is at or below the bottom of the fuel cell.  (Most external fuel pumps are meant to push fuel and not pull fuel.  Having the pump positioned as low as possible helps create a gravity assist in the line, which will help mitigate the chances of the fuel pump overworking itself) 
2. The external fuel pickup / outlet line that goes between the fuel pickup / outlet fitting on the fuel cell and the external pump needs to be as short as possible.  (The shorter the line, the less distance the pump has to pull fuel from inside of the fuel cell, which helps mitigate cavitation from occurring) 

It is critically important to properly plumb the extenal ven line properly to avoid vacuums and fuel surge instances from occurring. 

We have included a few steps below to ensure that your external vent line is plumbed properly. 

1. The external vent line must be plumbed vertically off the vent fitting so that there are no downward sags in it. 
2. Once you have plumbed the external vent line in a vertical direction that meets and or exceeds the tallest point in the fill system, you can then run the line downwards to where you want the line to vent to the atmosphere.  (A fuel surge out of the vent line can occur if you run the line downwards before the line has met or exceeded the tallest point in the fill system.) 

ENSURE THERE ARE NO BROKEN WIRES AND THAT YOU HAVE 12 VOLTS AVAILABLE AT THE SENDER AND GAUGE. 

ENSURE ALL WIRES ARE CONNECTED PROPERLY: 

1. POS terminal on sending unit connected to 12 Volt positive. 
2. NEG terminal on sending unit connected to 12 Volt negative (ground). 
3. SEND terminal on sending unit connected to Signal Input Terminal on gauge. 
4. POS terminal on gauge connected to 12 Volt positive. 
5. NEG terminal on gauge connected to 12 Volt negative (ground). 
   

ENSURE THAT THE OHM RANGE SPECIFIED ON THE SENDER MATCHES THE OHM RANGE SPECIFIED FOR THE GAUGE. CONTACT THE GAUGE MANUFACTURER FOR THE PROPER OHM RANGE. 

WHEN CALIBRATING THE SENDING UNIT TIMING IS CRITICAL. WHEN CALIBRATING EITHER EMPTY OR FULL A LITTLE LONGER IS BETTER THAN NOT LONG ENOUGH. IF YOU CANNOT CALIBRATE EMPTY OR FULL, ADD 2 SECONDS TO THE SPECIFIED NUMBER OF SECONDS AND TRY AGAIN. 

YOU MUST PROCEED IN THIS EXACT ORDER FOR EMPTY OR FULL CALIBRATION:

1. Start with the power off. 
2. Jumper the SEND terminal on the sending unit to the NEG terminal. 
3. Turn the power on. 
4. Remove jumper in the specified number of seconds (2 seconds for empty and 5 seconds for full). You must follow this procedure twice, once for empty and once for full. 

NEEDLE ON GAUGE DOES NOT MOVE AT ALL

1. Positive and Ground Wire are switched at gauge or at sender. 
2. No Power at sending unit. 
3. Broken Wire 
4. No ground 
5. Ignition switch is off 

>>Full was set at empty. 

>>Positive 12-volt dc or ground are not connected at gauge 

NEEDLE PEGS FULL

1. Mismatched ohm range between sender and gauge 
2. 12-volt positive is connected to the send terminal on gauge or sending unit 

NEEDLE PEGS EMPTY

1. Mismatched ohm range between sender and gauge 
2. Sending unit probe tube is in contact with water 

GAUGE NEEDLE DOES NOT TRAVEL FULL SCALE

1. Mismatched ohm range between sender and gauge 
2. Calibration or re-calibration is required