Fitting a HEI Module in Transistor Ignition Unit 1977 280Z

[HusseinHolland]

10 hours ago, Zed Head said:

Actually, in his drawing he does show the G and the W labels on the module.  You have to follow the green wire all the way to the module pin.  All of the modules have letter labels on the pins.  That has been my way to remember, the G on the module attaches to Green from the harness.  That leaves W for the red wire.

You seem to have it backward.  By the way, maybe you didn't notice but the red wire clamps on your original module have labels also.  G, R, L, BW, BW, B.  L = blue.

I see the G & W on his, I just have no clue what he means by W...

Not sure what you mean by having it backwards though - the Gn wire goes to Green-Red on the module side, the Red goes to Green-White

I am aware of the labeling on the wire retaining strip, I just didn't know if it was a difference between CA market & others, since there was another poster who said he had to reverse the wires compared to the same pic of his with the red on the outside...

Crop of his pic from directions

 

[Zed Head]

11 hours ago, Zed Head said:

G (harness) = Gn-R (module)

R (harness) = Gn-Wh (module)

The W on the module is from GM's labeling.  Might be that GM used a white wire.

In your writing above I thought that you were referring to the GM HEI module not the Nissan module.  Didn't realize you were deep in to the circuit board of the Nissan module, looking at those wires.  Most people just use the diagram or the labels on the wire clamp.

Don't know anything about the other person, but the basic test to see if the wires are connected correctly is to watch your timing light mark afterward.  If it jumps around it's probably backward.  If they're backward it won't hurt anything you just swap them.  There's an accurate edge of the variable reluctor signal and a fuzzy edge.  @Captain Obvious has some old comments about that.  

[HusseinHolland]

I mounted the HEI module/heat sink  to a bracket I made, that attaches to the side of the stock relay bracket, where the interval relay previously lived. Made it so the assembly is unscrewed from the face, as the bracket screws are otherwise inaccessible. I'll make a sub-harness so that the module can be removed with that attached

Edited September 17, 2023 by HusseinHolland

[Paulytunes]

13 hours ago, HusseinHolland said:

Thank you. On a side note, reading the FSM diagrams drives me nuts, since the wiring illustrations are from the terminal side of any given connector, compared to European format which is always viewed from wire side of any given connector. I'm already good at getting dyslexic with wiring, having to translate the pin locations in my head from the diagram to the reality just adds to the potential for error on my part. I always double-check my wiring anyway, with these it just takes even longer.

OK - So I'm going to assume the pin configuration he illustrates is still accurate for the HEI then, with Gn going to the small leg on the HEI

He doesn't actually list or show the physical wire transfer/connection within the module to the HEI pins:

G (harness) = Gn-R (module)

R (harness) = Gn-Wh (module)

Mine has 2 Blk/Wh wires, middle one appears to be redundant - since there is no connection on the module side. Not sure if I should join the 2 together for the HEI, in case there is some reason the 2 are required.

One note from my experience, when I connected my HEI, I ended up having to totally bypass the resistor.  I have a 1976, so my wiring was a bit different than yours.  I ended up connecting the B (blue wire) and C (Black with White stripe) to the Negative and Positive Ignition Coil Terminals, respectively.  Here is my thread for reference:  

Post #24 onwards is likely pertinent and may be helpful to you.  I initially thought this was a fuel delivery issue, so I posted it in the wrong part of the forum before other more knowledgeable members here steered me in the right direction.  I guess the good thing is that I did clear out my fuel vent lines, replaced my fuel filter, and developed a very good understanding of the fuel and ignition systems in my 280Z.  Good luck, and I hope this helps!

[EuroDat]

21 hours ago, HusseinHolland said:

Thank you. On a side note, reading the FSM diagrams drives me nuts, since the wiring illustrations are from the terminal side of any given connector, compared to European format which is always viewed from wire side of any given connector. I'm already good at getting dyslexic with wiring, having to translate the pin locations in my head from the diagram to the reality just adds to the potential for error on my part. I always double-check my wiring anyway, with these it just takes even longer.

OK - So I'm going to assume the pin configuration he illustrates is still accurate for the HEI then, with Gn going to the small leg on the HEI

He doesn't actually list or show the physical wire transfer/connection within the module to the HEI pins:

G (harness) = Gn-R (module)

R (harness) = Gn-Wh (module)

Mine has 2 Blk/Wh wires, middle one appears to be redundant - since there is no connection on the module side. Not sure if I should join the 2 together for the HEI, in case there is some reason the 2 are required.

Hi,

I accidently swithed the wires when I quickly connected the TIU for a photo. I noticed it a year or two later, but funny no one else has made a note of it until now.

The wiring for the HEI is correct. Trust me, when I was first testing it would not rev over 2500rpm. That was because I connected the two red - green wires on the TIU backwards

Working from left to right, looking at the TIU with the wires coming out from under the TIU.

B - Black wire: HEI Ground. Very important.

BW - Black/White wire: HEI B (battery)

BW - Black/White wire: Not used.

L - Blue wire: HEI C (Coil trigger "-")

R - Red wire: HEI W (reluctor input)

G - Green wire: HEI G (reluctor input)

You can set up the HEI next to the coil if you want. Just disconnect all the wires from the TIU. You can then use the power to the coil to HEI B and the HEI C terminal can connect to the coil negative. The blue wire on the coil negative will still need to be connected for the tacho to function. Make sure you ground the HEI well.

 

PS: Agree with you on the terminal layout in the electrical schema. I try to find a terminal that is not full. Say it has 7 wires in a 8 pin plug, then I can figure out which direction I need to look at it.

[EuroDat]

On 9/16/2023 at 3:42 AM, Zed Head said:

Might be why he decided to switch to a GM HEI.  Looks like his was wired backward somewhere along its journeys.

The FSM's all show Green on the outside.

Here's EuroDat's -

Here's 75 and 77 - 

Hi Zed Head,

The wires were switched accidently during testing. I'll take a new photo and update the Tech sheet. Funny thing, looking through my photos and I can't find that photo anywher. Must have deleted it.

 

Here is where my dyslexie kick in and it all when south for a moment..... 

I did start on the correct side and after running the engine which would not rev over 2500rpm, I corrected it and back on track.

[HusseinHolland]

9 hours ago, Paulytunes said:

One note from my experience, when I connected my HEI, I ended up having to totally bypass the resistor.  I have a 1976, so my wiring was a bit different than yours.  I ended up connecting the B (blue wire) and C (Black with White stripe) to the Negative and Positive Ignition Coil Terminals, respectively.  Here is my thread for reference:  

Post #24 onwards is likely pertinent and may be helpful to you.  I initially thought this was a fuel delivery issue, so I posted it in the wrong part of the forum before other more knowledgeable members here steered me in the right direction.  I guess the good thing is that I did clear out my fuel vent lines, replaced my fuel filter, and developed a very good understanding of the fuel and ignition systems in my 280Z.  Good luck, and I hope this helps!

Thanks for your experience, Paul. I had noted in EuroDat's directions that he bypassed the ballast. Since I'm using a Volvo 12v coil that didn't use the ballast to begin with, I am going to do as he did & bridge the ballast terminals, to keep the connections tidy.

[HusseinHolland]

1 hour ago, EuroDat said:

Hi,

I accidently swithed the wires when I quickly connected the TIU for a photo. I noticed it a year or two later, but funny no one else has made a note of it until now.

The wiring for the HEI is correct. Trust me, when I was first testing it would not rev over 2500rpm. That was because I connected the two red - green wires on the TIU backwards

Working from left to right, looking at the TIU with the wires coming out from under the TIU.

B - Black wire: HEI Ground. Very important.

BW - Black/White wire: HEI B (battery)

BW - Black/White wire: Not used.

L - Blue wire: HEI C (Coil trigger "-")

R - Red wire: HEI W (reluctor input)

G - Green wire: HEI G (reluctor input)

You can set up the HEI next to the coil if you want. Just disconnect all the wires from the TIU. You can then use the power to the coil to HEI B and the HEI C terminal can connect to the coil negative. The blue wire on the coil negative will still need to be connected for the tacho to function. Make sure you ground the HEI well.

 

PS: Agree with you on the terminal layout in the electrical schema. I try to find a terminal that is not full. Say it has 7 wires in a 8 pin plug, then I can figure out which direction I need to look at it.

Thanks for the confirmation, EuroDat. I thought about moving it the bay, much less wiring to worry about. Playing with placing the HEI & heat sink, I couldn't find a nice flat spot to locate it, except under the triangle steel web in the left corner near the AFM. Even though I don't plan on driving the car in the wet, the fact that the connections at the HEI are unsealed is enough for me to stick with placing it in the cabin 😁

Edited September 17, 2023 by HusseinHolland

[Captain Obvious]

13 hours ago, Zed Head said:

There's an accurate edge of the variable reluctor signal and a fuzzy edge.  @Captain Obvious has some old comments about that.  

Here's some info on that topic:
https://www.classiczcars.com/forums/topic/67864-ignition-systems-analysls/

It's a little academic (and unfinished), but I find it interesting. Might just be me. 

In any event, I'm hoping the module issues here with @HusseinHolland resolve themselves easily. We can get into some of the deeper details if they don't.

[HusseinHolland]

10 hours ago, Captain Obvious said:

Here's some info on that topic:
https://www.classiczcars.com/forums/topic/67864-ignition-systems-analysls/

It's a little academic (and unfinished), but I find it interesting. Might just be me. 

In any event, I'm hoping the module issues here with @HusseinHolland resolve themselves easily. We can get into some of the deeper details if they don't.

Hopefully I have no actual issues with the module in operation, this is all just about ensuring the wiring is accurate.

I wired the sub harness for the HEI module today

6.3mm spades for the connection to the factory harness

I made a bridge on the harness side, to connect both Blk-Wh together 

Edited September 18, 2023 by HusseinHolland

[Sjoost]

I did this modification back in 2020, and it has been running like a sunshine. I can't remember how I eventually hooked up the wiring, but I have no issue revving all the way up. I did jump the ballast resistor as per Eurodat’s instructions.

If you guys want me to re-check my config on the (early) 1976 California 280z let me know, I can make some photo’s.

[HusseinHolland]

Did the resistor bridge today, and installed the Bosch coil

original

center post snapped off, so I riveted the spade tang to the bridge. Doesn't really matter since the coils gets full battery voltage at any of the connections