1975 Datsun 280z(CA) HEI intstall questions

[palauoriginal]

Hello,

I am installing an HEI on a 1975 Datsun 280z(CA) non-turbo. There is not that much information on the exact subject but I took a look at some diagrams and it isn't that hard to grasp. The problem is that apparently I wired something wrong because my car isn't starting. Maybe its just something small that I'm missing.

 

Anyways, here are some diagrams of the process I took.

 

This is the stock setup.

 

Here is the set up i am using with the HEI module installed. Excuse the nasty MS paint.

 

 I have the outputs from my distributor connected, Red to W on the HEI and Green to G on the HEI.  B on the HEI is connected to the (+) side of the coil and C on the HEI is connected to the (-) side of the coil. The HEI is grounded with a wire.

 

The (-) side of the coil has two wires connected to it.

• The C connection
• The blue wire for tach signal and ecu pulse.

The (+) side of the coil has 4 wires connected to it.

• The B connection
• The stock condenser
• The B/W wire with constant 12v
• The black and blue wire with 12v on ignition

I'm using an accel super stock coil that I've had for some time now. I am getting random sparks on ignition on and no spark while cranking.

 

Any  input is appreciated.

[NewZed]

Make sure the stock igntion module is disconnected, and the wire ends insulated.  One possibility.

 

Otherwise, the connections look right.  That's how my 76 is connected.

 

And, by "HEI is grounded by a wire" you mean the mounting hole with the wide ferrule is grounded.  That's the important one, I believe.

Edited March 9, 2013 by NewZed

[Six_Shooter]

What do you mean by B/W wire has a constant 12V? Not affected by ignition switch position? If so, this will be a problem. The car will never shut off, if it did start.

 

It's been a while since I had the HEI module in mine running the coil (converted to DIS), but IIRC, I only needed the black white wire, which in my case was an ignition, not a constant.

 

Have you checked voltages at each terminal? With key on and while cranking?

 

Also, I found that I had a hard time starting the car when I had the red and green wires backwards.

 

--==EDIT==--

 

This might help:

http://www.zhome.com/ZCMnL/tech/gmhei.html

Edited March 10, 2013 by Six_Shooter

[palauoriginal]

And, by "HEI is grounded by a wire" you mean the mounting hole with the wide ferrule is grounded.  That's the important one, I believe.

 

I have the HEi module attached to an aluminum mounting/cooling plate underneath the coil/coil bracket. For one of the mounting holes on the HEI module, there is a metal area that comes out of the plastic. I figured that was the grounding area so I wired a wire to the chassis.

 

What do you mean by B/W wire has a constant 12V? Not affected by ignition switch position? ..... I only needed the black white wire, which in my case was an ignition, not a constant.

 

Have you checked voltages at each terminal? With key on and while cranking?

 

Also, I found that I had a hard time starting the car when I had the red and green wires backwards.

 

It was a switched 12v activated when it is "on" position(black/white). There is another wire that provides 12v (blue wire) for an ignition boost.

 

So, I just got back from work. I disconnected my old module. Tried it. No Start. Switched my R and G wires and Tried it. No start.

 

I am getting 11.9 ish volts from the b/w wire when key is "on".

 

Maybe its the coil or I messed up/recieved a damaged HEI module.

 

Thank you for responding!

[Tony D]

You realise the stock 75 Ignition in the 280Z is an HEI already, right?

[palauoriginal]

Tony, I didn't. I figured it was probably very similar though.

[NewZed]

 No Start. Switched my R and G wires and Tried it. No start.

 

 It should have run fine as you had it wired, red to W and green to G, IF it was running before and only the stock module crapped out. 

 

You never said why you were using the GM HEI module.  Did the engine run before? 

 

I have damaged a GM module by running my engine with only 4 spark plug wires attached.  After that it would only start with Starting fluid even when warm.  It would run, it just wouldn't start.  Installed a new module and it was back to normal.  Still not sure what exactly happened inside the module to do that.  I've seen other cases where people damaged the modules during installation.

[palauoriginal]

The car had been running prior to the swap so the original transistor ignition is probably fine. Honestly, I am trying to document the conversion and do a write up about it so others can use it if their ICM fails... but unfortunately I am running into difficulties, heh. I set up the conversion so it can be easily converted back to the original transistor ignition.

I may have damaged the module, I'll pick up a replacement one and test it when i get the chance. Luckily, I have a daily.

Edited March 12, 2013 by palauoriginal

[4.6StangRage]

I know the 280ZX distributor setup with the smaller ignition module is a by far simpler conversion. Look up that setup, i think it will work well if not better.

[TomoHawk]

We are discussing this and documenting it on classicZcars.com also.  Most people have the 1978 (with the federal setup)

www.classiczcars.com/forums/engine-drivetrain-s30/45070-gm-hei-upgrade-78-280z.html