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HybridZ

HEI 8 pin question


Nismo280zEd

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So I'm wiring up my new ignition module... real happy, finally going to get to drive the Z again, really nice day. Then I notice something. I'm looking at the wiring diagrams....

This one...

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And I don't know what to do with "B" that goes to pin6 on the db37 connector... so i look at how the MS is wired with non MSnSE and it goes into a relay, looks like it gets power. Or maybe I'm looking too hard and completely missed the obvious. (it happens)

 

Some clarification would be great, I wanna hear my baby run again!

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You can use several different pins depending on how you have wired the Megasquirt internally. I see you are using MSnS-E - you will need to add the spark output B mod, but you can send it to any available pin you wish. I'm using pin 29 on my Megasquirt.

 

The B pin is an override signal. With no voltage to the B pin, the eight pin HEI module acts like a four pin, firing the coil whenever it gets an input from the trigger. Apply voltage to the B pin, and Megasquirt can control the spark.

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Ok... I can't seem to find spark output B mod. The only thing i've found that comes close to what your talking about is the VR sensor mod.

 

I'm running a PCB 3.0 board w/ 021 MSnSE code i believe. I'm just trying to wire it up so i can use my VR sensor in my dizzy for my HEI control module lol.

 

-Ed

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  • 4 months later...

Bumping my old post instead of creating a new one. Was playing with the Z today, trying to get her up and running. Unfortunatley i'm having an odd problem and It's been so long since i've messed with MS i need some refresher help.

 

I did the above mode to run my HEI 8 pin module. It starts right off the bat but wont' idle. Been playing with idle screws, timing, fuel but not much improvement.

 

I can get it to start, idle starts to smooth out, jumps up to about 1000rpm maybe a little higher, at the same time my vacumn gets up to about 15 on my gauge Pressure on MS is droping into about the 50's then all of a sudden it dies. EVERY SINGLE TIME. I've been checking grounds, feeds, settings, etc. But not exactly sure where to go with this one. I figure it's something electronic cause when i feather the TB by hand I can't get it to idle either.

 

I've put a timing light on it, it's pretty close about 2deg off from MS says shouldn't be a big enough deal to cause my symptoms.

 

So in recap. I'm running 024s9 code on my V3 board with the LED19 or spark B mod on my 78 dizzy with welded internals to disable the advance with an HEI 8 pin ignition module. Also... on my LED's... when it starts... all three light up while it runs, then the one on the right dies out, then the left, then center. I thought my dizzy input used to the LED on the right but with the mod, i think it's the center one now?

 

Let me know what other kind of things I should check, going back over there tomorrow to work on it.

 

Thanks guys,

Ed

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I would hold the timing light on it while it goes through the whole dying process. If timing looks good all the way through, even when it cuts out and winds down to a halt, then maybe look somewhere else. Set timing in MS to fixed 10 BTDC to help make this easier.

 

We run the HEI 8 pin module in my friends TPI setup. The only problem he use to have was that the module would overheat because of no heat sink compound on it in the GM dizzy. It would run for a couple minutes, then die.

 

IT has been a long time since I helped him set up to use the 8 pin module, I can go back and look at my TPI install notes.

 

scratch that, I changed my thinking while typing this:

 

You know, your description sounds a lot like ASE settings. I have seen that a lot where the engine starts good, then leans out due to ASE and dies right away. For the first fire up I always set my ASE to at least 10 seconds (not cycles). The default for ASE is in processor cycles and is gone almost immediately after startup.

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Well i took the dizzy all apart again, it's a 77 so it has two pickups, i switched to the other pickup turned by hand and could hear it was working. So i removed the other one and rigged it to use this one for testing. Was trying to verify timing again on the motor but i couldn't see the mark as it was spinning, triger angle was at 60, set it to 30, then i could see the timing mark just past everything... set it to 10 and i got a large back fire. At this point it was about 9:30pm and I decided to call it a night, so i'm back home at my apt now. Didn't want to piss off my parents neighboors. I'll have at it again tomorrow... Also... checked my ASE settings... it was set for 250 cycles. I set it for 10 seconds now as recomended.

 

-Ed

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Yeah that sounds like the same problems I've been having. Just can't seem to find the right mark. I can get it running at -10, but Matt said that could be causing problem in the software and that I need to get it back to around 90 or 70. I didn't have much time to work with it either so had to stop early. I think I need to adjust my rotor some more to give me more advance.

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