70 Challenger RT - EFI 6 Pack Conversion

[70chall440]

Yes, but my ECU toggles the GND to turn on the pump. Not sure about the Holley.  I also use a diode to kill the flyback pulse when releasing. Make sure that you pay attention to polarity with the diode. If you hook it up backwards it open like a fuse and is worthless.
Remember. Electrons flow NEGATIVE to POSITIVE.

Leaving for a car show.  I'm out.

Lost me right after "yes"... That said, it appears if the diagram I posted will work. On the Holley system, it says the following;

"12V Fuel Pump - Color = Green - used to directly power a fuel pump (+12 volt). Fully terminated harnesses utilize a relay to supply this power. 14 gauge wire is used. Due to this, it is not recommended for pumps that draw over 10-12 amps to use this wire. For high current pumps, use this wire to trigger a separate relay and use larger gauge wire to feed the pump - 10 gauge wire is recommended."

So, in my mind the "green" wire would be wired to the positive side of the pump directly, UNLESS that pump draws more than 10-12 amps, in which case a relay would be required. That said, I do believe a relay is probably a good thing either way, but I am not running 10 gauge wire to the pump currently, I believe I am running 12 gauge.

[crash340]

Rob, its been too many years since I played with diodes, what size/type did you use

[roadman5312]

something like this?

                       I always wire 30 battery in, 87 out to pump, etc.  Wrong, or does it matter 

[70chall440]

                       I always wire 30 battery in, 87 out to pump, etc.  Wrong, or does it matter 

according to what I have looked at, no you are correct. However, a relay can be used in numerous ways and the way you are doing it is one of them, but the way I am proposing it works as well and allows you to "turn it on" with either the ECU or the switch.

[roadman5312]

according to what I have looked at, no you are correct. However, a relay can be used in numerous ways and the way you are doing it is one of them, but the way I am proposing it works as well and allows you to "turn it on" with either the ECU or the switch.

                                Cool     

[ShelbyDogg]

                       I always wire 30 battery in, 87 out to pump, etc.  Wrong, or does it matter 

30 or 87 doesn't matter unless you want to use a switch like me, then your pump should be at 30.

[ShelbyDogg]

Rob, its been too many years since I played with diodes, what size/type did you use

I bought a multipack assortment of 1N400x diodes from Radio Shack before they closed. Any small diode will  do.
A relay releasing is just like a small coil, it can shock you a little. You want to keep those pulses away from your computers.

Lost me right after "yes"... That said, it appears if the diagram I posted will work. On the Holley system, it says the following;

"12V Fuel Pump - Color = Green - used to directly power a fuel pump (+12 volt). Fully terminated harnesses utilize a relay to supply this power. 14 gauge wire is used. Due to this, it is not recommended for pumps that draw over 10-12 amps to use this wire. For high current pumps, use this wire to trigger a separate relay and use larger gauge wire to feed the pump - 10 gauge wire is recommended."

So, in my mind the "green" wire would be wired to the positive side of the pump directly, UNLESS that pump draws more than 10-12 amps, in which case a relay would be required. That said, I do believe a relay is probably a good thing either way, but I am not running 10 gauge wire to the pump currently, I believe I am running 12 gauge.

Your relay diagram is correct for a 12v supplied green wire to turn on the relay or pump. Use a relay to keep A shorted pump from killing the main Holley fuse and shutting down the ECU. Use a diode with the stripe on the + side of the relay coil. If you put the stripe on the ground side, you'll blow it.

[ShelbyDogg]

something like this?

On your diagram

Put your switch between 87 and 87a. Put your diode on between 85 and 86 with the stripe towards 86.

[dodj]

A relay releasing is just like a small coil, it can shock you a little. You want to keep those pulses away from your computers.

Lost me right after "yes"... 

440Chall, you can think of it as an ignition coil, when the power is cut off, the magnetism created by the windings induces an electrical pulse. With an ignition coil, it induces a large pulse because that is what it is designed to do. A relay has a small coil but it is still a coil. It induces a pulse into your electrical system every time you turn off the relay. Using Rob's diode idea, the pulse is shunted away from your electronics by giving it an easier path.

[70chall440]

dodj - thanks, appreciate the explanation.

[ShelbyDogg]

30 or 87 doesn't matter unless you want to use a switch like me, then your pump should be at 30.
[/quote

Your way, you can also hook your button between 30 and 87. That does the same thing.

[roadman5312]

                 I think you can buy relays that have a diode built in.   

[crash340]

 

[70chall440]

This effort has been very slow and consuming, I have also been distracted by several "honey do's", but it is moving. I checked the fuel system; yep it leaked a many places... but after some tightening it is now good. Then I begin to check out the wiring; I have decided to connect everything and see if it runs, if so, then I will route the harness and make it more permanent. This in turn has required me to make some fixtures, specifically for the battery so that I could connect all of the wires in addition to what I already have on there (battery tender, amp, etc). I am sure some of you will not like my solution, but it is what it is and I like it at least for now, beats having a pile of wires attached to the terminal ends.

I am not making a bracket for a relay to power the fuel pump along with a test switch. I should be trying to start it soon.

[70chall440]

Seems like this thing is taking forever... everything seems to require major effort and time, however it is moving. I have everything connected (temporarily) to see if it will run, however I have run into an issue with the distributor cap not being able to seat onto the body; the lock down towers on the side hit the head and/or the alternator spacer. I did have to "clearance" the head already to get the distributor to fit and seat correctly and now this. Not sure who designed this system but I am not real happy about it.

On a more positive note, I made my fuel pump test switch setup, as always it needed to be tweaked a little and  ultimately rewired as I got a wire connected incorrectly, however the up side is that it now works and I have tested it. I installed a little light so that I would not mistakenly leave the switch on. The light blinks which is cool, however it will also blink when the car is running and being powered by the ECU which isn't a big deal I guess, just wasn't expecting it to work that way. I will put up a wiring schematic later if anyone is interested.