ZR-1 Net Registry Forums - View Single Post - Jumper to avoid being stranded with a failed Primary Fuel Pump

QB93Z · 05-25-2015

After the fourth time that a failed primary fuel pump "stranded" a ZR-1 (mine once and three friends' ZR-1's). I decided to make an extension cable that swaps which fuel pump acts as pump # 1.

Background: If number 1 fuel pump fails, the LT5 will start properly but then die after a short period of time. When the engine is cold, the period may be almost a minute. When the engine is at operating temperature the engine will die immediately after starting.

This happens because the ECM energizes BOTH fuel pumps on engine start. So the Secondary Fuel Pump supplies fuel to the injectors while the primary pump does nothing. Once the engine is operating properly, the ECM turns off the Secondary Fuel Pump and the car stalls.

Here is my solution:

This jumper switches the wires in the plug to make the Secondary Fuel Pump get power from the Primary Fuel Pump's source. The jumper is pretty easy to install:

1. Pull back the rubber boot around the gas filler neck to access the wiring harness that is clipped to the rear facia:

2. Remove the small gray lock pin from the connector clip:

3. Separate the male and female halves of the connector:

4. Then connect the ends of the jumper into the circuit to the pumps.

5. Start the car to test the connections. As soon as possible, replace the failed primary fuel pump and remove the jumper.

6. I recommend that if you use the jumper to swap a failed primary fuel pump, you should turn the Power Key OFF (Normal). Without the second fuel pump operating, if the secondaries opened, there might be a problem with a lean condition due to insufficient fuel supply.

Based on the rules of Murphy's Law and Good Mojo, when I carry this jumper, I will never need it, just like the alternator that I have carried for about 30,000 miles of road trips that I haven't needed to use.

Enjoy the Road,

Jim

05-25-2015	#1
QB93Z Join Date: May 2007 Location: Westminster, Maryland Posts: 3,687	Jumper to avoid being stranded with a failed Primary Fuel Pump After the fourth time that a failed primary fuel pump "stranded" a ZR-1 (mine once and three friends' ZR-1's). I decided to make an extension cable that swaps which fuel pump acts as pump # 1. Background: If number 1 fuel pump fails, the LT5 will start properly but then die after a short period of time. When the engine is cold, the period may be almost a minute. When the engine is at operating temperature the engine will die immediately after starting. This happens because the ECM energizes BOTH fuel pumps on engine start. So the Secondary Fuel Pump supplies fuel to the injectors while the primary pump does nothing. Once the engine is operating properly, the ECM turns off the Secondary Fuel Pump and the car stalls. Here is my solution: This jumper switches the wires in the plug to make the Secondary Fuel Pump get power from the Primary Fuel Pump's source. The jumper is pretty easy to install: 1. Pull back the rubber boot around the gas filler neck to access the wiring harness that is clipped to the rear facia: 2. Remove the small gray lock pin from the connector clip: 3. Separate the male and female halves of the connector: 4. Then connect the ends of the jumper into the circuit to the pumps. 5. Start the car to test the connections. As soon as possible, replace the failed primary fuel pump and remove the jumper. 6. I recommend that if you use the jumper to swap a failed primary fuel pump, you should turn the Power Key OFF (Normal). Without the second fuel pump operating, if the secondaries opened, there might be a problem with a lean condition due to insufficient fuel supply. Based on the rules of Murphy's Law and Good Mojo, when I carry this jumper, I will never need it, just like the alternator that I have carried for about 30,000 miles of road trips that I haven't needed to use. Enjoy the Road, Jim __________________ If it isn't fun, you aren't doing it right! 1990 Black ZR-1 - sold 1993 Quasar Blue ZR-1 1994 Competition Yellow ZR-1 1995 Dark Purple ZR-1 Maryland State Coordinator WAZOO Member Last edited by QB93Z; 05-31-2015 at 10:06 AM.