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If I’m reading it correctly, the two wires that went to the tank on my 79 were a ground (flat spade on top of sending unit) and the pink ohms resistance circuit that sends the signal to the gauge; the rubber boot connector was the resistance/ full vs empty signal.
Easy enough to make a new weather craft that incorporates these two wires but what’s the best way to get power for my pump back at the tank when swapping to EFI??
you may have to take power from the fuse box from a circuit that is hot with the key on.
I've never done that before. Should I be using an unused fuse spot or reuse an existing one? -If the latter, do you have any recommendations of a good circuit?
-Should I be using a relay to keep the amps off of the stock wiring?
I think my Holley EFI supports 1 or 2 relays for this purpose so I'll reachout to my EFI guy Chris @ EFI System Pro to see what he thinks.
Run a dedicated pair of wires from the fuel pump to the front of the car.
You definitely need to use a relay (and a fuse) for the fuel pump.
I used the engine as my ground.
Use a suitable gauge wire- Many folks use 12 gauge or larger but for ease of packaging I used 14 gauge, which is still more than adequate for the length of the run considering the wires to the pump are typically 16-18 gauge.
Run a dedicated pair of wires from the fuel pump to the front of the car.
You definitely need to use a relay (and a fuse) for the fuel pump.
I used the engine as my ground.
Use a suitable gauge wire- Many folks use 12 gauge or larger but for ease of packaging I used 14 gauge, which is still more than adequate for the length of the run considering the wires to the pump are typically 16-18 gauge.
Thanks Ezobens!
I can't quite wrap my head around how that configuration would be physically run...
I'm thinking about an inline breaker instead of a fuse- mount it back by the rear bumper close to the fuel tank- then I could manually turn off the fuel pump, too (poor man's security system?).
Why would I run from the front of the car off of the alternator vs. from the battery? (DUH- finally figured this out- because I don't want the fuel pump running while the car is off-lol!)
I'm also confused on how the ground would work. My stock 79 sending unit has the pink wire for the resistance to run the fuel gauge and it also has a ground running from I think the back of the battery gauge in the dash. My thought is that I cut off the current "rubber boot" pink wire boot and the current female spade connector for the stock ground and wire them into a weatherpack connector to mate up with the current 1982 sending unit. -Then I would also connect the new dedicated ground that I'm running to the pump in that same wire in the weather pack connector and add the "hot" wire to power the pump.
Ezobens/anyone: Does this drawing make sense is this what I need to do?
Interpretation:
On the right hand-side in black and red "Train tracks" are the stock ground and pink ohms/full vs empty wire that went to the stock sending unit. -My thought is cut the connectors off and wire them into the weather craft plug to connect to the 82 sending unit. This will allow the stock gauge to work.
From the battery: Run new hot and negative wires from the battery, through a breaker, to a relay (I believe I only need to switch the "hot") -these will carry the load to the new EFI pump, but only when the "control signal" coming from a switched ignition source is on on the control side of the relay.
From the Fuse Box: Connect a low AWG pair of wires to an existing ignition-switched source from the fuse box all the way back to the "control in" side of the relay. -No real load will go through these wires so small AWG is fine -I think I'll run these next to the fuel return line.
Actual weather pack connector: Pink fuel level wire will go to the pink fuel level pin, the original ground and the new ground from the relay will go into the single ground in the 3 pin weather pack connector, then the new hot wire from the battery through the relay will go to the "hot" weather pack pin.
Scratch all of the above. Some of the features of my Holley EFI require that I give the relay control signal duty over to the EFI unit itself (ex: a feature that run the pump for 5 seconds after you turn the key through accessory mode so that all the fuel lines and rails are filled with fuel before you turn the key all the way on).
Yeah, the PCM needs to control the fuel pump relay.
The rest of your diagram should work- It's all about preference.
I preferred to have the fuel pump relay and wiring up front with everything else vs out back for ease of maintenance and trouble-shooting.
Since I am using a modified GM fuel module in the tank, I already had a convenient connector to plug it all in.
I also really didn't want to mess with running additional wires to the battery box (even though it's conveniently close) when I already had a 12 volt buss under the hood but it will work either way..
The fuel pump relay is built into the stock Holley HP harness (I have the TPI / Stealth Ram harness) and the relay is pretty physically close to the ECU side, it then has 6' of a single hot wire coming off of the relay that I run to the fuel pump sending unit's "hot" wire.
Then separately run a 14 gauge neutral wire straight from the battery and splice it into the weather pack connector's ground that the stock wiring sends from the gauge cluster.
Unfortunately, I learned that not all 3 wire Weatherpack connectors are the same- they have small little "cuts" in the plastic that lets them only work with other, identical Weatherpack connectors; I'm going to cut the stock one off of the 1982 sending unit over to the style that I have complete, matched male/female weatherpack connector for so they're all the same and work together.
The fuel pump relay is built into the stock Holley HP harness (I have the TPI / Stealth Ram harness) and the relay is pretty physically close to the ECU side, it then has 6' of a single hot wire coming off of the relay that I run to the fuel pump sending unit's "hot" wire.
Then separately run a 14 gauge neutral wire straight from the battery and splice it into the weather pack connector's ground that the stock wiring sends from the gauge cluster.
Unfortunately, I learned that not all 3 wire Weatherpack connectors are the same- they have small little "cuts" in the plastic that lets them only work with other, identical Weatherpack connectors; I'm going to cut the stock one off of the 1982 sending unit over to the style that I have complete, matched male/female weatherpack connector for so they're all the same and work together.
Adam
I have to do this same thing I think. I have the Terminator X Max, LS1 and a 82 sending unit in my 1980 Corvette. Did you ever find a weatherpack to run or did you just cut that off and run your wiring from your Holley to the external fuel pump wiring?
I know this is an old thread. Thanks for your response.
I have to do this same thing I think. I have the Terminator X Max, LS1 and a 82 sending unit in my 1980 Corvette. Did you ever find a weatherpack to run or did you just cut that off and run your wiring from your Holley to the external fuel pump wiring?
I know this is an old thread. Thanks for your response.
I just cut the stock connector on and bought a new 3 wire weather pack connector.
82 fuel sending unit wiring
