Fitting a HEI Module in Transistor Ignition Unit 1977 280Z

[HusseinHolland]

On 9/16/2023 at 9:23 PM, Zed Head said:

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.  

So today I ran the motor until it was warm , after checking the cold start circuit. I found that if I rev the motor to around 2k & hold it there, it hunts. Is this the condition others described that requires the reluctor wires to be reversed?

[Zed Head]

I haven't experienced it, only read about it.  Most people see it with a timing light.  The mark is erratic.

You could switch them and see what happens.  The voltage and current is the same.

[Mark Maras]

 A bit off-topic but in the past I've usually attributed an engine that "hunts" to be caused by a lean mixture.

[HusseinHolland]

1 hour ago, Mark Maras said:

 A bit off-topic but in the past I've usually attributed an engine that "hunts" to be caused by a lean mixture.

Indeed - however the only recent change to the EMS I've made is the HEI module - 'hunt' may not be the ideal term, even though it kinda feels like it - the motor won't rev as described by others in this thread when the reluctor signal is reversed.

[Zed Head]

Have you had a timing light on it?

Not clear why it would hunt at 2000 RPM but not at idle.  2000 is in the range of the centrifugal advance slope.  Have you been inside the distributor?

Engine RPM = twice distributor RPM.

[HusseinHolland]

29 minutes ago, Zed Head said:

Have you had a timing light on it?

Not clear why it would hunt at 2000 RPM but not at idle.  2000 is in the range of the centrifugal advance slope.  Have you been inside the distributor?

Engine RPM = twice distributor RPM.

 

The motor goes flat when revved, It is acting as described earlier in this thread. I'll put a timing light on it after work & see what's up. I'm going to reverse the reluctor wires first to see if that resolves it, since I can't rev the motor and watch the timing marker at the same time by myself. 

I have not touched the distributor other than to replace the cap & rotor.

Edited October 2, 2023 by HusseinHolland

[HusseinHolland]

I ran the motor & used the timing light, leaned over & revved the motor. Timing advances as expected when revved, and sits at approx 8º BTDC at idle.

The motor goes completely flat when revved & held at around 2500-3K. Fuel pressure does not falter, I have a line gauge after the filter. 

I tried reversing the wires from the reluctor, and that had very bad results. It cranked normally for a few revolutions, then turned over very slowly, then not at all. After that, it was completely dead. I thought the battery was drained - I found that cranking like that blew the 125 Amp fuse breaker on the starter cable from the battery. I replaced that, put the wires back & it started again normally. 

I don't understand why the ignition system is creating such an extreme current draw when the reluctor wires are switched.  No one has previously mentioned any issues with reversing the reluctor wires.

I tried another coil, in case that was an issue.

I'm going to put the stock module and coil  back in & confirm whether the issue is with the HEI conversion or not.

re-wired to plug into the modded harness

Edited October 3, 2023 by HusseinHolland

[HusseinHolland]

Swapped the coil & transistor module back in, however the middle post on the ballast snapped off when I did the conversion. Without that increased voltage when cranking, the engine is not starting. 

I'll have to see if I can get inside the ballast to add the intermediate post back tomorrow. In the meantime, I think I have to assume the SMP HEI module I bought is defective, the wiring is definitely correct. I've ordered a genuine AC Delco D1906 module to replace it. 

[Captain Obvious]

Swapping the reluctor wires should not draw anything that would ever pop a 125A breaker. And the wiring between the battery and that part of the car could not support that amperage level without smoking. Something else is going on.

Maybe the reversed reluctor was causing the ignition to fire at such an inappropriate wrong time that it was fighting the starter and you were getting locked rotor amperage through your starter?

And as for the ballast... I would be surprised to find that the spark is so  weak that it is preventing the car from starting. To test that, you could jumper straight across the ballast to get the car to start and then pull the jumper off as soon as it starts? Find out if it will run OK once you get it started? Do it quick so you don't overheat the coil?

[HusseinHolland]

19 minutes ago, Captain Obvious said:

Swapping the reluctor wires should not draw anything that would ever pop a 125A breaker. And the wiring between the battery and that part of the car could not support that amperage level without smoking. Something else is going on.

Maybe the reversed reluctor was causing the ignition to fire at such an inappropriate wrong time that it was fighting the starter and you were getting locked rotor amperage through your starter?

And as for the ballast... I would be surprised to find that the spark is so  weak that it is preventing the car from starting. To test that, you could jumper straight across the ballast to get the car to start and then pull the jumper off as soon as it starts? Find out if it will run OK once you get it started? Do it quick so you don't overheat the coil?

I definitely had none of these particular concerns prior to messing with the ignition system. When cranking (with reluctor wires flipped), it felt  like a motor that is way out of time, so perhaps that was causing the excessive drain. As it stands, with stock parts (and no increased voltage to ballast when cranking) within a short crank time, the voltage at the ballast is dropping to around 9v, according to my voltmeter.In any event, it won't start as is. So, I think I'll remove the ballast to see if I can fix it, and swap back the HEI connection & later coil, as at least I can run the engine at idle speeds that way & check the CSV operation again.

Edited October 4, 2023 by HusseinHolland

[Zed Head]

You can wire up the HEI module directly from the distributor wires and the coil power supply right next to the coil.  Forget about the ballast resistor entirely, at least for a quick test.  Or just use it as a terminal block.  The HEI module is current limiting.  The stock module is about 4.5 amps, I think, and the high performance ones about 7.  But that's just at the beginning of the coil charging cycle.  Should be fine.  It's all about heat and you can touch the parts to see how they're doing. 

[HusseinHolland]

So the issue with the ballast was that without the center post, there is no continuity.

repaired, then reassembled in outer casing

Started right up....but.... still hunts 2500-3000K rpm with stock module setup. So, moving on from ignition as the cause, most likely at this point would seem to actually be hunting due to lack of fuel volume - possibly crud in the fuel rail, since I did have all that apart to change the hoses.

YT vid of symptom