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6-pin connector melted

Today I was testing my system and I was not hearing the pump go. After some troubleshooting I realized I was getting very low voltage to the pump (about 3 volts). That's when I remember reading about issues with the 6-pin connector. Lo and behold it was my 6-pin connector melting the fuel pump pin. What a piece of junk! They sell a system with a fuel pump rating, but they don't design the proper connections. I have a 15 amp for my pump and I know it is rate to 12 amps. In any case, I have read that they may have shifted to a 4+2 connector. However, I don't feel like sending them my unit. My wiring harness has already been modified when I separated the blue and white wires from it. Now I am thinking to just add my own more beefy connector for the pump and battery. Any thoughts or experience? Any good recommendation on a connector to use?

1971 Mach 1 Mustang w/Ram Air, 408-4V stroked Cleveland, Hooker headers, FiTech EFI w/ RobBMC PowerSurge pump

I think I am going to go with a relay. I have so many already in the engine bay that I am trying to avoid adding one more but in this case it makes sense.

Has anybody tried to remove the pins from the Fitech 6-pin connector? If I use the relay I should be able to keep the same connector since I will be reducing the biggest draw. However, I may want to replace the pins.

1971 Mach 1 Mustang w/Ram Air, 408-4V stroked Cleveland, Hooker headers, FiTech EFI w/ RobBMC PowerSurge pump

So I backtracked and decided to not use a relay but cut the wires off the connector and purchase a properly rated plug. For kicks I contacted FiTech and they told me that I needed to upgrade the CPU for $234.99. What a ridiculous position! The 6-pin connecting plug was clearly underdesigned. Those small pins were never meant to handle 15 amps continuously. This being a design issue they should take care of it for free. My plug was melting on the inside. Who knows what would have happened if it would have occurred in a hot climate. Maybe even lead to a fire issue. Crazy! I will stick to my plan and purchase a Delphi weather connector.

1971 Mach 1 Mustang w/Ram Air, 408-4V stroked Cleveland, Hooker headers, FiTech EFI w/ RobBMC PowerSurge pump

My White wire would not make the connection inside of the plug.  Had to cut it and bypass the plug all together.  They didnt respond to two emails with pictures.

Why did you decide against the relay?  I am thinking the fuel pump output is determined via PWM, which would be lost in a relay, making the pump output 100% all the time.  Can you verify this?  I made matters worse by adding to the length of the circuit by installing my kill switch on the fuel pump line like I always do...and I also included an inertia switch, further adding to the length.  All of my added wiring was 12 ga, but you make a good point, the first wire from the battery to the unit is too small, after that, it doesn't really matter what upgrades I do, there won't be enough amperage getting there from the CPU.  So I'm thinking I'll run an 8 or 10 ga t0 replace the red wire, and put the relay there, and run the kill switch to the relay. So the kill will just cut all power to the FiTech ECM...Not going to start then, is it?   Then just replace as much of the orange wire as I can with  10 gauge and an inline fuse.  Anyone see an issue with that plan?

anwat sadat
Quote from 7.4 4x4 on April 23, 2020, 9:04 pm

Why did you decide against the relay?  I am thinking the fuel pump output is determined via PWM, which would be lost in a relay, making the pump output 100% all the time.  Can you verify this?  I made matters worse by adding to the length of the circuit by installing my kill switch on the fuel pump line like I always do...and I also included an inertia switch, further adding to the length.  All of my added wiring was 12 ga, but you make a good point, the first wire from the battery to the unit is too small, after that, it doesn't really matter what upgrades I do, there won't be enough amperage getting there from the CPU.  So I'm thinking I'll run an 8 or 10 ga t0 replace the red wire, and put the relay there, and run the kill switch to the relay. So the kill will just cut all power to the FiTech ECM...Not going to start then, is it?   Then just replace as much of the orange wire as I can with  10 gauge and an inline fuse.  Anyone see an issue with that plan?

When I installed my system I only left about 4" of the pump and 12v feed wires on the off-engine side of the harness. I used 14 ga the rest of the way to the battery and pump. That only leaves me with about 2 feet back and forth on the engine side of the harness at 16 ga, and the rest at 14 ga. My 14 ga run is about 4 ft on the pump side and 6 ft on the 12v feed side.

RarestAce and 7.4 4x4 have reacted to this post.
RarestAce7.4 4x4
1971 Mach 1 Mustang w/Ram Air, 408-4V stroked Cleveland, Hooker headers, FiTech EFI w/ RobBMC PowerSurge pump

It's under the hood I go then, I'll stick with 12 ga instead of 1o for the pump, 10 for the main power lead.  Funny to think they would risk catastrophic failure of the unit and their reputation for a few cents of copper...I know it's expensive, but come on, we've all heard the horror stories of using too small a conductor and all the issues it can cause.  Just out of curiosity, does anyone know what the other aftermarket fi systems use for the fuel pump lead?  Or do they just leave it up to you to wire up?

And just out of curiosity, why did FiTech say you needed to upgrade your CPU?  What could possibly be related between the issue of melting plastic plugs and the computing going on in the unit?  Unless maybe there's a command prompt to melt the plug hidden in there somewhere...very odd.

anwat sadat
Quote from 7.4 4x4 on April 25, 2020, 12:07 pm

It's under the hood I go then, I'll stick with 12 ga instead of 1o for the pump, 10 for the main power lead.  Funny to think they would risk catastrophic failure of the unit and their reputation for a few cents of copper...I know it's expensive, but come on, we've all heard the horror stories of using too small a conductor and all the issues it can cause.  Just out of curiosity, does anyone know what the other aftermarket fi systems use for the fuel pump lead?  Or do they just leave it up to you to wire up?

And just out of curiosity, why did FiTech say you needed to upgrade your CPU?  What could possibly be related between the issue of melting plastic plugs and the computing going on in the unit?  Unless maybe there's a command prompt to melt the plug hidden in there somewhere...very odd.

My fuel pump had a 14ga, but curious to see what does Holley do?

I assume that the wire harness is soldered to the CPU so that's why they want you to replace it.

 

7.4 4x4 has reacted to this post.
7.4 4x4
1971 Mach 1 Mustang w/Ram Air, 408-4V stroked Cleveland, Hooker headers, FiTech EFI w/ RobBMC PowerSurge pump

I just looked at the wiring diagram for Holley's Terminator EFI ECU.  They use a 14GA power wire.  I actually think the wires are pretty normal for any harness.  This is my 4th LS car, and even the factory harnesses are small wires.  I think properly wired and grounded systems with soldered connections are the key.  No doubt if you're running a massive external fuel pump a thicker gauge wire is a great idea.  I snipped mine and added 12GA back to my pump.

I ended up purchasing a Delphi Weaher Pack 2-pin connector (p/n 12015792) for the 12v feed and pump. This connector is rated to 20 amp. My pump wire has a 15 amp fuse next to the pump to protect the ECU.

With this mod, the original 6-pin connector is of no use. I already have the white and blue wires going through another connector right off the unit. If I ever go to timing control, I will get the black wire out of the harness as well. The 6-pin connector may be used in the future for the fan control.

1971 Mach 1 Mustang w/Ram Air, 408-4V stroked Cleveland, Hooker headers, FiTech EFI w/ RobBMC PowerSurge pump