Which wire to connect the Holley EFI ?

[340 Slapstick]

I am doing the final wiring on the Holley EFI on my 1970 Gran Coupe 340 stock wiring . which wire is the best and at which point to connect the pink wire (Needs to be a clean 12v and 12v while cranking) Which wire and what color is it??
Thanks For the HELP.

 

[Chryco Psycho]

The Blue wire to the Ballast, voltage Reg & Alt is 12v Run the the brown wire also at the Ballast is 12v Crank so both need to connect

 

[340 Slapstick]

The Blue wire to the Ballast, voltage Reg & Alt is 12v Run the the brown wire also at the Ballast is 12v Crank so both need to connect

Thanks! I will try that.

 

[moparroy]

Or use those two diode isolated to hold a relay then used the relay to deliver true 12v to the EFI all the time. Regular likely less sensitive. That's what Holley recommended in one discussion.

 

[340 Slapstick]

The Blue wire to the Ballast, voltage Reg & Alt is 12v Run the the brown wire also at the Ballast is 12v Crank so both need to connect

I tried it but those wires both cut off when the key is turned to start.

 

[340 Slapstick]

Or use those two diode isolated to hold a relay then used the relay to deliver true 12v to the EFI all the time. Regular likely less sensitive. That's what Holley recommended in one discussion.

Can you be more specific? I know very little about wiring-just enough to get in trouble.

 

[moparroy]

Sorry I'm in the hospital way the moment so limited in what I can do /draw. I can send you a sketch probably later in the week. The diodes are to stop run power from flowing into the start circuit and vice versa. I would also suggest you fuse the 3 leads to be safe esp if you are not fully comfortable with wiring. 3 being run start and battery. Yours being a 70 assume it's a single ballast? Vs my double. There should be start only power on one side of the ballast for ballast bypass for starting.

 

[340 Slapstick]

Sorry I'm in the hospital way the moment so limited in what I can do /draw. I can send you a sketch probably later in the week. The diodes are to stop run power from flowing into the start circuit and vice versa. I would also suggest you fuse the 3 leads to be safe esp if you are not fully comfortable with wiring. 3 being run start and battery. Yours being a 70 assume it's a single ballast? Vs my double. There should be start only power on one side of the ballast for ballast bypass for starting.

Sorry to hear you’re in the Hospital. By double ballast I guess you mean 4 prongs. Mine has 4prongs.

 

[Chryco Psycho]

There is a blue 12v wire going to both sides of one end of the ballast , there is a brown wire to the other side of the ballast that will bypass the ballast & give 12v to the coil while cranking , installing a diode to prevent back feeding the brown circuit is a good idea

 

[340 Slapstick]

There is a blue 12v wire going to both sides of one end of the ballast , there is a brown wire to the other side of the ballast that will bypass the ballast & give 12v to the coil while cranking , installing a diode to prevent back feeding the brown circuit is a good idea

So I connect the pink Holley wire to the blue wire where the 2 blue wires are? Which side of the ballast? Then what? Where do I put the diode? I guess I’m having trouble visualizing this.

 

[Chryco Psycho]

both blue wires on the one end are 12v , the diode needs to go on the brown wire on the other end of the ballast , in needs to supply 12v while cranking but not allow voltage back into that circuit while running .

 

[340 Slapstick]

both blue wires on the one end are 12v , the diode needs to go on the brown wire on the other end of the ballast , in needs to supply 12v while cranking but not allow voltage back into that circuit

So I connect the pink wire to one of the blue wires on one end and then use a jumper wire from there up to the brown wire with a diode in line?

 

[moparroy]

Keep in mind the diode is polarized ie it matters which way it goes. I used a 4Amp diode. Go to an electronics store and ask for a 4A rectifier or switching diode either should work. 4A is overkill probably but that way it stays cool. The diode should be a small cylinder about 1/4 inch dia and length. One end of the cylinder will have a silver stripe painted around it. That is the cathode or negative end which goes toward the blue wire allowing +ve current to flow from the brown to the blue during cranking but not the other way

 

[moparroy]

Btw i used 2 diodes to keep run insulated from start also.
So one diode from blue to pink and one from brown to pink. Both cases the pink "to" side is the cathode or stripe end.
With only one diode the start or brown wire can feed power to run cct blue wire for things that are not normally powered during start or cranking. I believe the voltage regulator and thus the alternator is one example.

 

[340 Slapstick]

OK is it normal for my ballast resistor to be hot?

 

[moparroy]

Yes for sure. That's why it is in ceramic

 

[340 Slapstick]

ok that wiring set-up did not work. called Holley and they said to just hook up the one wire to the fuse panel or the wire coming off of the ignition switch. If I can trust my multimeter it appears that I’m not getting 12v at those points

 

[moparroy]

I was told ballast ignition can be problem for aftermarket EFI.
So how is your ballast getting hot without 12v??
It may be there is just too much noise as this is close to the coil and spark action.
Did you try powering a relay instead of Holley directly?
I don't know 70 specifically but my 74 had two distinct wires from the ignition switch for run (blue) and start. (Brown s and maybe yellow).
if you hook it up to the fuse panel battery side it will be on all the time and kill your battery.
on accessory no cracking power.
food for thought

 

[340 Slapstick]

No I didn't try powering a relay, what does that mean. Keep in mind I know nothing about auto electrical.

 

[340 Slapstick]

OKAY, update.
I was able to start it today off of the blue wire from the ignition switch. I also discovered I have a short of some kind that kept it from firing, it would only crank yesterday. today it wouldn't even crank until I moved wires. so I have some investigating to do but at least I know it will run!! THANKS to everyone who weighed in to help.