Duffy's 1/71 Series 1 240z build

[Zed Head]

Just a thought (more mud maybe).  There are other big wires up there that carry a lot of load and could easily be tapped to power the ECU.  A relay controlled by the ignition switch and power from one of those wires and you've got solid power and no worries about overloading the ignition switch or those other crusty old wires.  Relays don't pull much, and you run brand new wire for the new load.  There's a good color wiring diagram in the downloads area, for pondering.

https://www.classiczcars.com/files/category/1-wiring-diagrams/

[SteveJ]

1 hour ago, duffymahoney said:

Steve, is this your idea? I try to not cut any stock wires or drill any holes. I did my entire ITB install without a single new hole in my low mileage series 1. 

 

Going back to my detailed instructions, here is how you find the wire I suggest you use.

First locate the wire junction in the passenger footwell. (Mine looks different because it's a 73.) Find the connector(s) that have BW wires.

When you find it (them), disconnect the engine side from the dash side. (You can see the engine harness going through the firewall.

 

Make sure the BW wire is disconnected from the ballast resistor and use a clip lead to ground it to the shock tower. (I have a bullet connector on the BW in my car due to modifications I made.)

Ground the black lead on your meter. Take a spade lug and plug it into the connector where there is a BW wire. Check resistance.

If you aren't seeing low resistance, (My meter is displaying the 1 well to the left of the decimal to indicate "open line") move the spade lug to another BW wire and test again.

Eventually you should find the correct wire. (It's a little blurry, but I hope you get my point.)

You can back out that pin and create the circuit I described earlier. The reason for the short piece of wire and connector before the inline fuse is in case you ever need to pull the engine wiring harness, you can still pull it through the hole in the firewall just by disconnecting between that wire and the inline fuse.

This is how the circuit would look as I described it earlier. I just selected a random pin on a six pin connector to represent what you might see. The actual pin location may be different.

You can just leave the old BW wire that went to the Engine Harness connector dangling if you want. It's dead.

Is this more work than what you proposed? Certainly, but with this there is little risk to the wiring harness or Haltech wiring.

[SteveJ]

I forgot to mention that my method does not leave a live BW wire in the engine bay, so that further reduces risk.

[duffymahoney]

16 hours ago, SteveJ said:

I forgot to mention that my method does not leave a live BW wire in the engine bay, so that further reduces risk.

I will leave all the wires in the engine bay where they are supposed to be, I will most likely heat shrink and wrap.  

I have to pull my condenser and see how hard it would be to get to that plug. I have never seen any of those:) 

[duffymahoney]

16 hours ago, SteveJ said:

I forgot to mention that my method does not leave a live BW wire in the engine bay, so that further reduces risk.

Thank you for all the help! I was using my defrost 12v positive for my pink haltech keyed 12v, which now seems to be a terrible spot for it.  

 

I currently don't have my G/W wire going into the tach and no black and white coming out of the tach, my tach works perfectly as is, from reading the wiring diagram, I don't see it branching out or affecting anything else?  Am I wrong about that?  

Could that be a good spot to get keyed 12v?  Since I am not using it at all?  Pull that plug out of the ignition plug, then add a new fused pink wire(ecu keyed 12v) into that spot?  

[SteveJ]

The harness interface in your car will have different connectors. They changed between 72 and 73.

Your car will have something like this:

The BW wire I suggested you find will be in the big 4 wire or 6 wire connector.

 

[SteveJ]

2 minutes ago, duffymahoney said:

Thank you for all the help! I was using my defrost 12v positive for my pink haltech keyed 12v, which now seems to be a terrible spot for it.  

 

I currently don't have my G/W wire going into the tach and no black and white coming out of the tach, my tach works perfectly as is, from reading the wiring diagram, I don't see it branching out or affecting anything else?  Am I wrong about that?  

Could that be a good spot to get keyed 12v?  Since I am not using it at all?  Pull that plug out of the ignition plug, then add a new fused pink wire(ecu keyed 12v) into that spot?  

I would not recommend the defroster circuit for the Haltech.

It's hard for me to say anything about the GW wire since I don't have detailed photos of your engine bay to see how things are connected now. All I can say is that the way I suggested is safer because you won't have a 12VDC+ wire hanging out in your engine bay doing nothing but waiting for a short circuit to happen. (I don't like abandoned wires that could be hot.)

[duffymahoney]

1 hour ago, SteveJ said:

I would not recommend the defroster circuit for the Haltech.

It's hard for me to say anything about the GW wire since I don't have detailed photos of your engine bay to see how things are connected now. All I can say is that the way I suggested is safer because you won't have a 12VDC+ wire hanging out in your engine bay doing nothing but waiting for a short circuit to happen. (I don't like abandoned wires that could be hot.)

G/W wire isn't connected to anything in the engine bay (abandoned not being hot is smart). Currently it is not hot, since it no longer goes into the tach.  It is unplugged.  The G/W on my keyed ignition seems to be an empty spot for 12v keyed.  Unless I am not reading the wiring diagram correctly.  

[SteveJ]

There aren't any spares on the ignition switch.

The GW wire at the ballast resistor would have 12VDC+ during starting. You can back the pin out of the engine harness side of the connector to prevent shorting.

Alternatively, if you need the Haltech powered while starting, do the following:

1. In the engine bay, replace the connectors for the BW (Ignition switch one, not the coil positive one) and GW wires to a male/female insulated set and plug them into each other. 
2. Use the GW wire at the tach to run to an inline fuse and on to the Haltech.

Since I have never played with the Haltech, I cannot tell you whether or not this is beneficial.

[duffymahoney]

B/R ignition switch wire. 51.1 ohm. Bad?

[duffymahoney]

B/Y ignition wire. .7ohm 

[duffymahoney]

B/W ignition plug wire