Fitting a HEI Module in Transistor Ignition Unit 1977 280Z

[Sjoost]

EuroDat & Kyle 146,

I am facing issues on my 280z 1976 (stall after initial startup, too rich, after while bit unstable) , and I have checked all and have now reached the Ignition coil. My resistance values on my coil primarily are 1.8 ohm and resistor is around 1.3 ohm (3.1 which i understand is too high anyway). NewZed from Hybridz directed me to EuroDat's HEI change over as his hint was that it could be my Ignition Unit gone bad. Thx for the nice writeup EuroDat. That will help me a lot.

Just to make sure, are the HEI's still working for you guys? And what about the unstable needle of the RPM meter?

I did notice the discussion on the red and green wire's. I was reading trough my 1976 FSM EE and found that there is actually a different wiring it seems, between the California model and the Non-California model. Could that be the strange difference Kyle had, compared to the EuroDat's setup?

Take care,

 

Joost

Edited December 30, 2020 by Sjoost

[wheee!]

I have a non California 76 HEI unit available in the classifieds...

[kyle146]

9 hours ago, Sjoost said:

EuroDat & Kyle 146,

I am facing issues on my 280z 1976 (stall after initial startup, too rich, after while bit unstable) , and I have checked all and have now reached the Ignition coil. My resistance values on my coil primarily are 1.8 ohm and resistor is around 1.3 ohm (3.1 which i understand is too high anyway). NewZed from Hybridz directed me to EuroDat's HEI change over as his hint was that it could be my Ignition Unit gone bad. Thx for the nice writeup EuroDat. That will help me a lot.

Just to make sure, are the HEI's still working for you guys? And what about the unstable needle of the RPM meter?

I did notice the discussion on the red and green wire's. I was reading trough my 1976 FSM EE and found that there is actually a different wiring it seems, between the California model and the Non-California model. Could that be the strange difference Kyle had, compared to the EuroDat's setup?

Take care,

 

Joost

Currently I went back to the stock Transistor Ignition Unit on my car with the mindset "if it aint broke dont fix it" but i keep the HEI in my car just in case. As far as what I remember about doing this project, yes when I reversed the red and green wires the car ran right. Even after replacing the HEI in case of a weird fault. As far as color differences, I know that every single year of 280z's had different wiring. Looking at your image and corelating it with my FSM does show that the image is the same but it does appear that it wants me to check continuity of the primary circuit on a different wire. Maybe my car being a California car just makes it weird. Who knows, regardless Im not currently running the HEI right now. It ran great on the car for a week but I think due to me buying not a really good unit (a duralast cheap one from autozone) the HEI would miss a little at high RPM's. Let us know though if this fixes your problems and maybe someday I will come back to this project and run an HEI again. 

-Happy Holidays

[Sjoost]

Kyle146,

 

will do once I get the items in. Hard to get in Holland, or against crazy prices.

take care,

 

joost

[EuroDat]

On 12/30/2020 at 11:34 AM, Sjoost said:

I did notice the discussion on the red and green wire's. I was reading trough my 1976 FSM EE and found that there is actually a different wiring it seems, between the California model and the Non-California model. Could that be the strange difference Kyle had, compared to the EuroDat's setup?

Take care,

 

Joost

Hi Joost,

The difference between the models 280Z is

Non-California model distributors up to July 76:
Manual, D6F4-01, dual pickups.
Auto, D6F4-02, dual pickups, same as 01, but has a different vacuum advance pot.

There is a 6 degree phase difference between the pickups that is activated by a temperature switch. 

California model distributor:
Manual & Auto use the D6F4-03, both with a single pickup.

When the temperature switch activates the TIU changes from one pickup to the other to retard or advance the timing.

If you use this distributor with the HEI module, then connect the red and brown or brown and green. The brown is the common wire between the two pickups. Connecting the red and green to the HEI will give you a dubble wave 6 degrees apart.

 

After July 76 they all used the single pickup distributor and matching TIU. The 78 model uses a connector plug in the TIU and a 12 volt coil, no ballast resistor. I'm not sure what the resistor value is in the 78 tacho. Being a 12volt coil, it could have a higher resistance.

[HusseinHolland]

Bringing this back. I printed EuroDat's directions for reference.

Honestly, the main reason for me to do this is to free up space - I need to add extra relays up under the dash, and the transistor ignition module is extremely bulky.

I'm going to use a Bosch power stage heat sink as the form factor & pin locaters are identical, so it will occupy significantly less space than fitting the HEI inside the OEM box

Volvo/Bosch coil for 90's model application. Different center post connection, however I already had Kingsborne wires made when I converted the ignition on my old X1/9, so the coil wire will work perfectly for the Z. Primary resistance value of this coil is in the ballpark suggested. Not a fan of aftermarket brand coils, so this will work for me.

It would be even easier if a Bosch power stage could be used, since they are mounted in the bay with waterproof connection. 

SMP HEI Module & Bosch Heat Sink

 

[Captain Obvious]

On 9/13/2023 at 9:37 PM, HusseinHolland said:

It would be even easier if a Bosch power stage could be used, since they are mounted in the bay with waterproof connection. 

Quick web search indicated that the Bosch unit is triggered by a hall effect sensor and therefore does not contain the circuitry to deal with the Datsun VR pickup. Bummer. Would have been a neat modification.

[Zed Head]

I've posted about this before...many people use the GM HEI module in place of the "Ignitor"/power transistor on the 280ZX ECCS systems.  Which should be a 5 volt square wave.  I've wondered why it works when, in theory, the HEI module triggers on the switch from negative voltage to positive (maybe vise-versa, can't remember).

Just one of those things I've wondered about.  I had a theory about transistors but don't have the knowledge to rationalize it in words.  But, in short, it might work even though it's not designed for it.

[HusseinHolland]

@EuroDat - I removed my module today, and the wiring of the red & green is reversed compared to your directions. Mine is a CA market 75 280Z

 

[Zed Head]

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 - 

Edited September 16, 2023 by Zed Head
Pictures got screwed up

[HusseinHolland]

11 hours ago, 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 - 

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.

Edited September 16, 2023 by HusseinHolland

[Zed Head]

1 hour ago, HusseinHolland said:

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)

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.