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

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

Demps · 05-25-2015

Genius!

Part numbers and source(s)...sorry if I missed them.

Ted

Dynomite · 05-25-2015

Just so I understand this Jim......

The jumper you made up can be much shorter as it is only used to just switch wiring within the connector?

Exactly which wires are switched?
We have green, white, red, black wires from bottom to top on each side of the connector.
Green (on right) now goes (in your jumper connector) to what color (on left) and so on? I assume only two wires are switched....which two wires?

Great concept/solution Jim

Thanks

Oh....Jim I do carry tools and a volt meter (drivers side box), Jumper Cables and Nylon Tow cable (passenger Side Box) behind seat. I also carry a Tow Bar Adapter located between passenger seat and door sill with Lug Nut Wrench.

I have never carried a spare alternator

QB93Z · 05-26-2015

Quote:

Originally Posted by Dynomite

Just so I understand this Jim......

The jumper you made up can be much shorter as it is only used to just switch wiring within the connector?

Exactly which wires are switched?
We have green, white, red, black wires from bottom to top on each side of the connector.
Green (on right) now goes (in your jumper connector) to what color (on left) and so on? I assume only two wires are switched....which two?

There are four wires in the connector:

Black - DC ground
Purple - Fuel level sensor signal to the fuel gauge display
Gray - 12 vdc to a fuel pump
Lt Green (or Green/White) - 12 vdc to the other fuel pump

My short jumper is just a cross-over jumper, as Cliff said. By switching (crossing) the gray and green wires, the 12 vdc from the Primary Fuel Pump is routed to the Secondary Fuel Pump.

The part number for the connector on the harness (car side) is:

Connector, elec, Fuel Pump, Male GM 12085534 (AC Delco PT145)

Here is the part on Amazon:
http://www.amazon.com/ACDelco-PT145-.../dp/B000C9SNX0

I haven't verified by ordering the connector for the pump side of the connection. I got the connector I used from a take-out fuel pump assembly from WAZOO donated parts. I THINK (but haven't verified) that GM 88861069 is the female connector, but I can't find a source with a picture.

Jim

Dynomite · 05-26-2015

Quote:

Originally Posted by QB93Z

I haven't verified by ordering the connector for the pump side of the connection. I got the connector I used from a take-out fuel pump assembly from WAZOO donated parts. I THINK (but haven't verified) that GM 88861069 is the female connector, but I can't find a source with a picture.

Jim

Thanks Jim

I am not so sure about that GM88861069 for female connector. I cannot find that on Amazon. If someone finds a source of that female connector that would be great......

GOLDCYLON · 05-26-2015

Hmm i'm piecing some parts together. If it works out I could make a small run of these to those who are interested if Jim is not adverse to it. Jim any issues since its your idea ?

Kevin · 05-25-2015

I need one of these

PhillipsLT5 · 05-25-2015

Quote:

Originally Posted by Kevin

I need one of these

Me too

Hib Halverson · 05-26-2015

Why not jump the secondary fuel pump test connection to the battery?

Isn't that easier?

QB93Z · 05-26-2015

Quote:

Originally Posted by Hib Halverson

Why not jump the secondary fuel pump test connection to the battery?

Isn't that easier?

The Fuel Pump Test Connection in the wire bundle near the ECM cannot power the fuel pumps when the ignition is ON.

The fuel pump test connection is very useful when 12 Vdc is applied with an ammeter. A running fuel pump will draw about (I don't remember the exact number) 4 amps. If the ammeter reading is > 8 amps, then two pumps are running in test mode.

Jim

05-25-2015	#1
QB93Z Join Date: May 2007 Location: Westminster, Maryland Posts: 3,684	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 Last edited by QB93Z; 05-31-2015 at 10:06 AM.

05-25-2015	#2
Demps Join Date: Jan 2006 Location: Niceville Posts: 999	Re: Jumper to avoid being stranded with a failed Primary Fuel Pump Genius! Part numbers and source(s)...sorry if I missed them. Ted

05-25-2015	#3
Dynomite Join Date: Aug 2009 Location: South Dakota/California Posts: 3,816	Re: Jumper to avoid being stranded with a failed Primary Fuel Pump Just so I understand this Jim...... The jumper you made up can be much shorter as it is only used to just switch wiring within the connector? Exactly which wires are switched? We have green, white, red, black wires from bottom to top on each side of the connector. Green (on right) now goes (in your jumper connector) to what color (on left) and so on? I assume only two wires are switched....which two wires? Great concept/solution Jim Thanks Oh....Jim I do carry tools and a volt meter (drivers side box), Jumper Cables and Nylon Tow cable (passenger Side Box) behind seat. I also carry a Tow Bar Adapter located between passenger seat and door sill with Lug Nut Wrench. I have never carried a spare alternator __________________ Clickable links On Iphone Touchable Links -Solutions- LT5 Modifications/Rebuild Tricks Low Mileage ZR-1 Restoration 1990 Corvette (L98) Modifications LT5 Eliminated Systems LT5 Added Systems LT5/ZR-1 Fluids 1995 LT5 SPECIFIC TOP END REBUILD TRICKS Last edited by Dynomite; 05-25-2015 at 08:41 PM.

05-26-2015	#6
GOLDCYLON Join Date: May 2007 Location: Peoria, AZ Posts: 9,117	Re: Jumper to avoid being stranded with a failed Primary Fuel Pump Hmm i'm piecing some parts together. If it works out I could make a small run of these to those who are interested if Jim is not adverse to it. Jim any issues since its your idea ? __________________ GOLDCYLON - 91 ZR-1 #2014 GOLDCYLON - 90 ZR-1 #2794, 4L60e (Formerly Schrade's) GOLDCYLON - 11 CTS-V Arizona State Director 91 WHITE/BLACK #2014. 380 P&P&PCed,Ported Heads, Jeal Long tubes, Corsa Exhaust/FIKSE FM-5s /LED TLs, LED Headlights, Front Wilwood 6 piston narrowlite calipers and rear Wilwood caliper street shop mod,CNCed Coolant Pipes,TPI Cvr,Filter cover,Stainless Bolts, DRM/DOM PROM /ZFDOC mod build #102,DRLs,BMAD with stainless Debris Screen,Coplan Air Blaster, Pioneer APP Radio 4,Brey-Krause HB,Sub Bar,Fire extinguisher seat mount,DRM Coilovers,LEDs everywhere,Compass mirror (orange),V1 DIC hidden display, Homelink sun visor, Carbon Fiber top x3 and APSIS Carbon Fiber interior, APSIS CF Steering Wheel/NAPA Leather, Banski trailing arms, Guldstrand front suspension,urethane bushings from Prothane (total suspension) ZFDoc drive shaft safety loop, raptor shift light (orange),AO engineering louver front plate, Console seat cushion, 96CE seats with black custom Sheepskins, ss billet catch can,Viper remote entry/alarm,Cragar Rear Louvers,LED side louver lights, Dewitts Radiator with SPAL fans and a Woods 160 T-Stat 90 RED/BLACK #2794. 4L60e Automatic Stage V by RPM Transmission, TCI Dedicated TCM, OBX Stainless Headers, Corsa Exhaust, SAN Secondaries and Haibeck PROM, Exotic Muscle Coil overs, LED Interior Lights, LED Tail Lights, LED Headlights, 94 Sport seats with black custom Sheepskins , Cragar rear louvers, GS Front calipers, Banski Trailing arms, APSIS Carbon Fiber steering wheel, Front and Rear Baer Eradispeeds, DRLs, Guldstrand front suspension,urethane bushings from Prothane (total suspension), Dewitt's Raditor with Dual SPAL fans and a Haibeck 170 T-Stat 11 RED/GREY CTS-V

05-25-2015	#7
Kevin Join Date: Jun 2005 Location: pittsburgh Posts: 4,624	Re: Jumper to avoid being stranded with a failed Primary Fuel Pump I need one of these __________________ It's not the car, it's the people - Doug Johnson 90 r/r "KEYS ON" nick named "T.L.B"

05-26-2015	#9
Hib Halverson Join Date: Jun 2005 Location: CenCoast California Posts: 898	Re: Jumper to avoid being stranded with a failed Primary Fuel Pump Why not jump the secondary fuel pump test connection to the battery? Isn't that easier? __________________ Hib Halverson Technical Writer former owner 95 VIN 0140 current owner 19 VIN 1878