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Duffy's 1/71 Series 1 240z build


duffymahoney

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Get resistance readings, not tone. I think I have mentioned in one of my YouTube videos that you can get a "false positive" with a tone.

Also please be more descriptive with your measurement techniques and testing procedures. Where you put your probes is important. 

Here's an example, for the B/Y wire, it goes through the solenoid and on to ground. If the wire is connected at the solenoid, you could read the resistance of the wire in the solenoid when doing a measurement. Depending upon how your meter is set up, that may set off the tone.

If you're not too experienced with multimeters, these videos may help.

 

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9 minutes ago, duffymahoney said:

I was putting a positive lead into the ignition plug and getting a tone on each of those wires.  

What meter are you using? Does it only have one lead? Take photos of your testing setup and don't skimp on details. 

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Duffy,

Don't want to complicate all the info you're receiving. Your in need of a 12v switched lead? Your running a Haltech Elite 750 that has a 34 pin main connector on top of the ECU, you must have a 34 pin harness connector? correct, Pin 26, looking at the connector on the top of the ECU, lower left corner, 12 v switched connection for multiple components.  

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On 8/15/2022 at 7:45 AM, duffymahoney said:

The coil positive has a full short in it.

 

5 hours ago, duffymahoney said:

But I found my first melted wire.

I don't want to muddy up the waters either.  But a "full" short would completely fry the insulation and the wire very quickly.  That wire has just seen too much current for too long.  But there is a load, some resistance, between the source and the ground somewhere.  Have you measured resistance through that IAC valve?  Easy to do and worth verifying.

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57 minutes ago, Zed Head said:

 

I don't want to muddy up the waters either.  But a "full" short would completely fry the insulation and the wire very quickly.  That wire has just seen too much current for too long.  But there is a load, some resistance, between the source and the ground somewhere.  Have you measured resistance through that IAC valve?  Easy to do and worth verifying.

That's why I'm trying to get more information on the testing methods. There could be a hot spot from corrosion at the black/white, possibly short duration short circuit in the past, or someone tapping into that circuit downstream, increasing the load on the circuit.

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Posted (edited)

I will start doing more testing later.  I will get details on my meter and what I am seeing.  I feel like this all started when my son decided to leave my car in the on position overnight.  But maybe not.  

 

The short is strong enough now, to drop voltage down enough to cause the haltechs relays to drop connection and cause the ecu to turn off, while cranking.  It's how I started down this fun rabbit hole.  I can also smell, burnt wiring when the key goes to on.  Sadly it's not as simple as just finding another keyed 12v for the haltech, I will need to fix this properly.  

Edited by duffymahoney
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That's a good piece of the puzzle. Did you have the points ignition or a first gen Pertronix in the car when he did that?

The worst case scenario is that I can probably walk you through making a replacement for that wire that you can "graft" into the dash harness. You know you wanted to have a reason to pull the dash. 😉 

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2 hours ago, SteveJ said:

Did you have the points ignition or a first gen Pertronix in the car when he did that?

I think that he has a Hall sensor on a modified Jeep CAS.  And he has coil on plugs, AKA COP, controlled through the Haltech system.  Could be a coil circuit in the Haltech ECU, or the tach circuit with all six coils ganged, or maybe the Hall sensor on the CAS.  

Lots of things to check.  Meter time.  Check, check, check , check...

image.png

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17 minutes ago, Zed Head said:

I think that he has a Hall sensor on a modified Jeep CAS.  And he has coil on plugs, AKA COP, controlled through the Haltech system.  Could be a coil circuit in the Haltech ECU, or the tach circuit with all six coils ganged, or maybe the Hall sensor on the CAS.  

Lots of things to check.  Meter time.  Check, check, check , check...

image.png

So that would beg the question about where he tapped into the ignition circuit to begin with since he said he didn't know how the circuit was routed. More questions than answers.

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Posted (edited)

First test. This is one of the black and white wires for the ballast/ coil. Grounding to my shock tower. Klein  MM200 multimeter. 
 

Both the behind the tach is unplugged and so is my keyed ignition 

3F009352-9707-44B8-ADCF-3CF193D44F04.jpeg

Edited by duffymahoney
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4 hours ago, SteveJ said:

So that would beg the question about where he tapped into the ignition circuit to begin with since he said he didn't know how the circuit was routed. More questions than answers.

Well I thought I knew exactly what it was. 12v positive for the coil. Which I wasn’t using. Since I have coil on plug. Getting fed directly from my ecu. I thought it was a simple way to wire my iac. But that turned out to be less. I regret it for sure.  It would have been easier by a lot, to just run a circuit off my haltech. Whoops 

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11 hours ago, duffymahoney said:

First test. This is one of the black and white wires for the ballast/ coil. Grounding to my shock tower. Klein  MM200 multimeter. 
 

Both the behind the tach is unplugged and so is my keyed ignition 

3F009352-9707-44B8-ADCF-3CF193D44F04.jpeg

Now THIS is something I can work with. The good news is that this wire is not shorted to ground. While 15 ohms is low resistance, you could be reading through other branches on the circuit. That resistance would equate to less than 1A of current when energized. You just don't want the end of the wire floating around in the engine bay where it could short while you're driving. 

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1 hour ago, SteveJ said:

Now THIS is something I can work with. The good news is that this wire is not shorted to ground. While 15 ohms is low resistance, you could be reading through other branches on the circuit. That resistance would equate to less than 1A of current when energized. You just don't want the end of the wire floating around in the engine bay where it could short while you're driving. 

Well interesting, I will have to look which wire this is, ballast or off the back of the tach, I assume an ohm reading will be best for that.  I see the ballast circuit goes off to other branches, and would be a not as nice spot for me to tap 12v from.  I will ohm check the rest of the ignition wires, but they also seem to go off and branch.  I will put a fuse inline no matter what I do.  

What circuit would you tap for the keyed 12v to my haltech?  Behind my dash I found two, one was defrost(unplugged since I got the car) and the other is a ?.  I was using the defrost, it's just a relay switched 12v, so very thin wire, so I assume low amp draw.  

 

1 hour ago, conedodger said:

Steve, gather your tools and head for Idaho. Beer is on Duffy. Oh, and some late season wakeboarding!

I do own a brewery and a wakesurf boat:) Come on up. 

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Duffy,

Have a 73, so don't want to assume your stock ignition harness is the same wire color combo. Remove ignition switch cover behind the steering wheel and test the 5 pin connector plugged to the back of the ign key switch. Believe it's the B/W wire for 12v switched on (it's been a year and reassembled). Attach the pink wire from the Haltech ECU. 

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If I was doing the wiring, provided the following conditions are true.

  1. There is no need to make the wiring easily reversible.
  2. There is no need for the wiring on the old ignition circuit.
  3. You are just needing the main 12VDC switched source for the Haltech.

Here is my thinking.

  1. Buy two latching 1 pin connectors from Vintage Connections
  2. Buy some extra male and female pins for this type connector. 
  3. Buy an open barrel crimping tool if you don't already have one. (Amazon link for a crimping tool)
  4. Buy an inline fuse holder.
  5. Identify which BW wire at the engine harness/dash harness is the one on the ignition circuit, noting the connector and position. (I'll detail how to identify the wire later.)
  6. Back out the pin for that BW wire from the connector on the engine harness side. (Vintage Connections tool)
  7. Cut a short length of wire, maybe 3 to 4 inches. On one end, crimp a female pin onto the wire and insert into the female 1 pin connector. On the other end of the wire, crimp a pin that matches the type you backed out in step 5, and put it into the engine harness connector to replace the wire you backed out.
  8. Strip, crimp the pins, and put the male and female connectors onto the wires of the inline fuse holder.
  9. On pink Haltech wire, crimp on a pin and attach the remaining connector to plug into the one on the end of the inline fuse holder.
  10. Use no larger than a 10A fuse in the inline fuse holder.
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26 minutes ago, Blitzed said:

Duffy,

Have a 73, so don't want to assume your stock ignition harness is the same wire color combo. Remove ignition switch cover behind the steering wheel and test the 5 pin connector plugged to the back of the ign key switch. Believe it's the B/W wire for 12v switched on (it's been a year and reassembled). Attach the pink wire from the Haltech ECU. 

It is the BW wire. However, if Duffy connects the pink wire at that point, there is no protection for the wiring. That's why my instructions are as detailed as they are. Mind you, I do controls engineering for emergency power, so I do look at how to prevent the magic smoke from escaping from the wires.

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Agree without the Haltech premium wiring harness (safeguard investment). The prem harness runs all ECU connections back through intergraded expandable fuse and relay box (pink ign wire 12v switched and all battery connections included). 

Not not sure what Duffy has for a harness?

 

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Yeah, I have already de pinned the B/W wire from behind the ignition switch, I believe I have a few extra connectors for the stock pins.  So install it there, inline, but fuse protect it.  That makes perfect sense to me.  

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28 minutes ago, Blitzed said:

 

Agree without the Haltech premium wiring harness (safeguard investment). The prem harness runs all ECU connections back through intergraded expandable fuse and relay box (pink ign wire 12v switched and all battery connections included). 

Not not sure what Duffy has for a harness?

 

It has an expandable fuse and relay box.  I have 4 open fuse spots.  2 open relay spots.  

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Just now, duffymahoney said:

Yeah, I have already de pinned the B/W wire from behind the ignition switch, I believe I have a few extra connectors for the stock pins.  So install it there, inline, but fuse protect it.  That makes perfect sense to me.  

By removing the BW wire from the ignition switch, you also remove power from the following:

  1. Tachometer positive
  2. Turn signals
  3. Voltage regulator (If you did the internally regulated alternator swap, this is used as the switched source for the alternator.)

You'll either need to use a Haltech switched source and find a place to connect into the wiring (Please don't hack the wiring.) or take a path like my directions.

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10 minutes ago, duffymahoney said:

My basic plan for the pink wire. 
 

Using the B/W spot for my pink wire. Then use the haltech fuses to give 12v to my iac. 

C74F5BDF-854F-4D11-B1DC-548EBC973498.jpeg

And you will not have

  1. Tachometer positive (tachometer function)
  2. Turn signals
  3. Proper alternator function.
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Hi Duffy,

Do not remove the B/W wire from the connector, splice into the wire using a copper U shaped crimp connector and heat shrink. Leave the connector intact for all other functions. This connection (pink wire) will only power up the ECU when the key is in the on position. Again, I'm safe guarded with the fuse box inline on the harness. Running for a year with this config, no issues, blown fuses and all stock electrical components function. 

Don't touch your tach, give me a call. 

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