Fitting a HEI Module in Transistor Ignition Unit 1977 280Z

[kyle146]

14 minutes ago, kyle146 said:

And as soon as i put the hei back on, timing is off and it runs like crap. Again out of curiosity I reversed the red and green to see if it would rn and it starts up with no problem. Going to try to see if it will rev past the 3000 mark

Ok wow no clue whats going on but reversed the green and red and timing is right and revs all the way up and no issues whatsoever. I literally have no idea why it works with the wires reversed but it does. The timing is right, the advance is right and the acceleration is right. Im now running the green wire on top and the red on bottom and it works perfectly. I definitely did not reverse any wires so Im not exactly sure whats going on?

 

Edited August 29, 2019 by kyle146

[EuroDat]

I'm not sure what is going on, but hey, it runs the way it should. Thats the main thing.

[Captain Obvious]

I'm not going to get into which direction is right for your application, but those two wires... the red and the green... Are polarity dependent and can certainly have an effect if reversed.

Most (if not all?) ignition module systems use the falling edge zero crossing as the trigger. It's the most reliable point of the pickup signal.

 

[kyle146]

4 minutes ago, EuroDat said:

I'm not sure what is going on, but hey, it runs the way it should. Thats the main thing.

 

1 minute ago, Captain Obvious said:

I'm not going to get into which direction is right for your application, but those two wires... the red and the green... Are polarity dependent and can certainly have an effect if reversed.

Most (if not all?) ignition module systems use the falling edge zero crossing as the trigger. It's the most reliable point of the pickup signal.

 

 Honestly I have no idea whats going on and why the reversing of wires works. Im going to keep the old ign box with me just in case this is a fluke and keep the ballast resistor on just so its easy to swap the old ign box back in if the hei goes haywire. I know there is a logical explanation for this but hey if there is someone out there who is struggling to get this mod to work and reversing the wires does work then by all means do it. Ive driven it around for 20 minutes (idle and some high revs) and both the hei and the coil are not extremely hot but warm to the touch. I will update after one week of driving and see what happens. After that week is up, then ill bridge the ballast resistor. Thank you guys for all your help! This has been both a little odd but fun mod!

[kyle146]

On 8/29/2019 at 1:28 PM, kyle146 said:

 

 Honestly I have no idea whats going on and why the reversing of wires works. Im going to keep the old ign box with me just in case this is a fluke and keep the ballast resistor on just so its easy to swap the old ign box back in if the hei goes haywire. I know there is a logical explanation for this but hey if there is someone out there who is struggling to get this mod to work and reversing the wires does work then by all means do it. Ive driven it around for 20 minutes (idle and some high revs) and both the hei and the coil are not extremely hot but warm to the touch. I will update after one week of driving and see what happens. After that week is up, then ill bridge the ballast resistor. Thank you guys for all your help! This has been both a little odd but fun mod!

Ok so update time! Been driving the car all week with the wires reversed and ballast resistor still active. Today was the day I wanted to bridge the ballast resistor. After I bridged it, it started up just as normal and ran fine. Only little issue was the Tach was freaking out. It was stuttering and all over the place. To rectify the issue I turned off the car, Reattached the resistor terminals to the resisted side and started it again. Tach functioned like normal. I had then Isolated it down to either the grounding was bad or the Blue in line resistor underneath the glove box area was not enough. So I cleaned grounds and bridged the resistor to 12 volts again... same thing, tach all over the place. I then grabbed a 5k Potentiometer I had made with bullet connectors and put it in line with the resistor. Tach functioned fine until I revved and then acted slightly erratic again but not too much. Which told me that I needed a higher resistor. Pulled out a 10k Potentiometer with bullet connectors and connected it just by itself and adjusted the knob to about halfway and started the car. Tach worked perfectly and if it was a little slow I would just turn down the knob a little. Ill be driving all this week with it on 12 volts. I even cleaned and gapped the spark plugs for the new spark it will be receiving.  

[EuroDat]

Well, you have had a bit of a struggle getting there, but at least you now have a good working systeem. I can't remember having any trouble with the tacho, but I'm not sure if it is accurate either.

[Zed Head]

19 hours ago, kyle146 said:

Ok so update time! Been driving the car all week with the wires reversed and ballast resistor still active.

You never really said where red and green were to start so it's unclear what reversed is.  But if your timing light is steady they're probably right now.  Green goes to G and red goes to W, normally.

I had a similar problem with my tach and the HEI module.  I fixed it by putting a condenser/capacitor on the negative (blue) wire that feeds the tach,  I assume that there was electrical noise generated by the HEI and the condenser knocked it down.  I know it worked because many miles later the tach started acting up again and I found that the wire to the condenser had broken.  Reconnected it and the tach was back.

[kyle146]

25 minutes ago, EuroDat said:

Well, you have had a bit of a struggle getting there, but at least you now have a good working systeem. 

Yeah im happy to see it all in good working order!

17 minutes ago, Zed Head said:

You never really said where red and green were to start so it's unclear what reversed is.  But if your timing light is steady they're probably right now.  Green goes to G and red goes to W, normally.

I had a similar problem with my tach and the HEI module.  I fixed it by putting a condenser/capacitor on the negative (blue) wire that feeds the tach,  I assume that there was electrical noise generated by the HEI and the condenser knocked it down.  I know it worked because many miles later the tach started acting up again and I found that the wire to the condenser had broken.  Reconnected it and the tach was back.

Well when I did this project the red and green were just how the wiring diagram specified. Green going to G and Red going to W but that made the car run odd. Until i put the Green on W and Red on Green to try it out and then it worked!

 

Do you have a condensor/ capacitor recommendation by chance? Just so im not throwing in random types 

 

Thanks guys!

[Zed Head]

I used one from a spare alternator that I had laying around.  Used the ground bolt on the manifold to mount it and ran the wire over to the coil post.  I had to extend the wire though so there might be a more convenient mounting location.  You can get that type at any auto parts store for a few bucks.  By adding resistance to your coil power line you're reducing the strength of the spark at higher RPM, defeating the HE part of the HEI module, so it might be worth an experiment.

On the red-green thing, you have two many wires in your picture, it's hard to know what's what.  You might trace those wires back to the pickup coil itself and see what is connected where at the distributor.  Maybe they're mixed up at the pickup coil.  The HEI module is very sensitive and might even work with just one wire.

[EuroDat]

I used my original condensor, but eventually removed it.

[280zdude]

I’m new to the z cars found an old barn find. Anyways I have no spark and this system seems like it would fix any wiring issues ups in the car. 
 

Question 1) does this basically delete the ignition relay? 
 

Question 2) with a multimeter i checked the (black and white wire) on the ignition relay and the (red and white wire )on the ignition switch and they are showing -12 volts. Does that seem off to you? Shouldn’t it be +12 volts. 

Question 3) The black and white wire which connects to the resistor is not getting voltage. Where should I check for continuity? or how do you think I should go about that? 
 

im guessing if I do the HEI it will allow me to by pass all the wiring that’s been messed with trying to figure out this situation to find spark. 

 

Sorry for reviving an old thread but you guys seems like you know a lot! 

Edited December 23, 2020 by 280zdude

[SteveJ]

2 hours ago, 280zdude said:

I’m new to the z cars found an old barn find. Anyways I have no spark and this system seems like it would fix any wiring issues ups in the car. 
 

Question 1) does this basically delete the ignition relay? 
 

Question 2) with a multimeter i checked the (black and white wire) on the ignition relay and the (red and white wire )on the ignition switch and they are showing -12 volts. Does that seem off to you? Shouldn’t it be +12 volts. 

Question 3) The black and white wire which connects to the resistor is not getting voltage. Where should I check for continuity? or how do you think I should go about that? 
 

im guessing if I do the HEI it will allow me to by pass all the wiring that’s been messed with trying to figure out this situation to find spark. 

 

Sorry for reviving an old thread but you guys seems like you know a lot! 

1. No. The HEI would replace the Transistor Ignition Unit (TIU). The ignition relay takes the burden off of the ignition switch. Instead of all of the current for circuits powered in the ON position going through the ignition switch (and decreasing the life of the switch), most of the current goes through the ignition relay that is cheaper and easier to replace should it fail.
2. Your measurement has no meaning without context. What position was the key in? Which probe (positive and negative as plugged into your meter, not color) was touching where? The white/red wire should have 12VDC to ground all of the time. The black/white wire should have 12 VDC to ground  with the key in the ON position. (Notice that I say "to ground". This means the negative probe of the meter should be touching the chassis of the car. You can use an unpainted bolt connected to the body for this.) If you are touching the negative probe to the white/red wire and positive probe to the black/white wire, you could see -12 VDC displayed on your meter if the key is not in the ON position or if the ignition switch is bad. 
3. The black/white wire at the ballast resistor is electrically the same as the black/white wire at the ignition relay. For the ballast resistor, the black/white wire runs from the ignition switch, through connector C-3 (and C-2), and over to the ballast resistor. If you have the key in the ON position, as I said in #2, you should see 12VDC to ground on the black/white wire on the ignition relay. If you do not have 12VDC to ground there, you will likely not have 12VDC to ground at the ballast resistor. At that point, it is likely that you have a bad ignition switch.