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240z electronic ignition help


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I'm trying to convert my 240z from points and condenser to electronic ignition. I bought a new '79 280zx distributor, cap, and rotor. Also an MSD 12 volt coil and an HEI module.

I used info from different writeups to determine the wiring. A previous owner had removed the ballast resistor and noise-suppressing capacitor. I tried to start it up today but it won't start. I have 11 volts at the coil + terminal.

I modified a diagram from a writeup to show how I wired the new parts in. If anyone sees anything obvious I missed I'd appreciate some input.

Maybe a ground for the module C terminal?

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Forget the HEI module, put the ZX dizzy black box back on, and wire it up like this.

 

e1280x.jpg

Now remember, you have a 240-Z so your 12+ is coming from your tach, so it will hook to the + on the coil and the "B" terminal on the module. Also, make sure you have jumpered accross the ballast resistor...if you just remove it, you will get no voltage to the coil, you must jumper it.

Edited by Dtsnlvrs
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Appreciate the input. If I can't get this to work I may have to use the e1280. I'm not giving up on this yet though. I think it may be a ground problem. I'm going to check tomorrow to make sure the HEI module has a good ground.

 

 

Why??? the E12-80 is a far superior ignition controller. I think the HEI module should belong on a Chevy. Some Chevy owners may disagree as they dont like them either. I have personally tried going the HEI route...many moons ago...before pertronix...and disliked the results sooo bad, that I went back to points! It would flutter and stumble at high rpm, and was inconsistent all across the board.

 

Datsunzgarage.com

 

CHEVY HEI MOD

Using a GM HEI module is a 25 year old way to put a 1975-78 280Z distributor on a 240. The problem is that the GM HEI was designed for the low redline of a V8 and is well-known for it's poor spark saturation abilities above 4,500rpm, even Chevy people hate them. I've heard of people adding a HEI chip onto their 280Z or ZX ignition which makes no sense. Why would you add a HEI chip on top of the existing electronic ignition setup?

 

Even on it's own I consider the HEI a poor mod for performance and I don't recommend it: Back in 1996 I used a 1977 280Z distributor and HEI on a SU carb L28 I had built. It pinged easily for some reason and I was never sure exactly why, so I quickly I converted over to a 280ZX distributor with a E12-80. The E12-80 sells for $200, the HEI module for $20, you be the judge.

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I did the HEI set up with no issues... no stumbling. Chevy used HEI 74-87. I doubt it would have been used so long if it didn't like over 4500rpm. also GM previous years has proven to have cheap replacement parts, the higher dollar modules ~$40 are made of better materials. 160 bucks less to fix my car?? oh yeah! I got a bad module from a junkyard dizzy, nothing pisses you off more than random no spark... replaced with HEI used on 2.4 with rv cam, header. while learning to go fast without beating my car up it seen many an RPM... no miss also used with blaster 2 coil. I liked it. still have it in a box o crap. went turbo, than v8

.02

Edited by tyler031734
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I would second the other posters, you don't really need to integrate a HEI module as the E12-80 transistor ignition does the job quite nicely.

The problem with HEI modules is that only the connectors are standardized, but the output current, dwell management and current control is not. It depends on the manufacturer and type if the HEI module handles dwell on its own, and does current control. A state of the art ignition module has electronic dwell control, and an intelligent current management to feed up to 8A to the coil (standard HEI modules do around 4A).

 

Regarding your HEI setup, the wiring looks correct but make sure that you have a proper ground connection of the module as it won't work without one (you already mentioned that you will check for this one). You do not need a condenser with a transistor ignition, as there is no mechanical switch (points) for the coil current.

If you have a multimeter, you want to check that there is a small voltage at B and C when you turn the starter. If you can measure a small voltage, then the pickup is ok (if not, remove the HEI module and measure the pickup for a low resistance to make sure it not broken).

Next, remove the B and C wires from the coil and connect a small +12 bulb to it. It should flash with a low frequence as soon as you engage the starter. If the bulb does not flash, the HEI module is most probably broken (but check the ground connection first).

 

good luck,

Adrian

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I would second the other posters, you don't really need to integrate a HEI module as the E12-80 transistor ignition does the job quite nicely.

The problem with HEI modules is that only the connectors are standardized, but the output current, dwell management and current control is not. It depends on the manufacturer and type if the HEI module handles dwell on its own, and does current control. A state of the art ignition module has electronic dwell control, and an intelligent current management to feed up to 8A to the coil (standard HEI modules do around 4A).

 

Regarding your HEI setup, the wiring looks correct but make sure that you have a proper ground connection of the module as it won't work without one (you already mentioned that you will check for this one). You do not need a condenser with a transistor ignition, as there is no mechanical switch (points) for the coil current.

If you have a multimeter, you want to check that there is a small voltage at B and C when you turn the starter. If you can measure a small voltage, then the pickup is ok (if not, remove the HEI module and measure the pickup for a low resistance to make sure it not broken).

Next, remove the B and C wires from the coil and connect a small +12 bulb to it. It should flash with a low frequence as soon as you engage the starter. If the bulb does not flash, the HEI module is most probably broken (but check the ground connection first).

 

good luck,

Adrian

Thanks Adrian, that was helpful. The only reason I mentioned the ballast resistor was because a PO had already removed it and modified the wiring and used a stock coil replacement and the tach isn't working. I must have worded the original post badly because I had no plans to install a resistor. Getting rid of the points and resistor was the motivation for doing this. I guess I was wondering out loud if the wiring the PO did might have prevented the tach from getting a signal.

There is 1 volt on the distributor side of the module. I tried a ground wire to the module but it still won't fire. The module is high quality bought from Summit.

I'm going to wire the e1280 module back in just to try to get the car running. I'll probably try the HEI module again some other time.

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Mike,

 

i never mentioned the ballast resistor :wink:

 

BTW, you can also test the HEI module functionality by putting a wire across G and W, when removing the wire a spark should be triggered.

And I appreciate that :) Using the info from your posts the module is good and the wiring is correct. But it still doesn't run /shrugs. Obviously I did something wrong. Maybe I need to test the distributor.

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And I appreciate that :) Using the info from your posts the module is good and the wiring is correct. But it still doesn't run /shrugs. Obviously I did something wrong. Maybe I need to test the distributor.

 

Correct, If bridging G and W created a spark, you need to check the distributor pickup. A basic test would be to remove the red/green wires to the HEI module and measure the resistance of the pickup using a multimeter on red and green. You should see a reading somewhere around 1000-2000 Ohm. If you dont see a resistance, then the distributors pickup coil is broken, but this happens rarely.

 

A thorough test of the pickup requires a scope so you can see the waveform generated by the pickup when turning the distributor.

You already measured a voltage of around 1V (should be a bit less at starting speed though and the multimeter needs to be in AC mode), but i would assume that the pickup is ok when you see a voltage as soon as the distributor turns.

A a further test: you could switch the red an green wire to the HEI (red on G, green on W). This just changes the polarity of the output signal, it wont break anything. Be aware that with the wrong polarity your timing will be off, so just use this as a functional test of the pickup/HEI Module.

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Correct, If bridging G and W created a spark, you need to check the distributor pickup. A basic test would be to remove the red/green wires to the HEI module and measure the resistance of the pickup using a multimeter on red and green. You should see a reading somewhere around 1000-2000 Ohm. If you dont see a resistance, then the distributors pickup coil is broken, but this happens rarely.

 

A thorough test of the pickup requires a scope so you can see the waveform generated by the pickup when turning the distributor.

You already measured a voltage of around 1V (should be a bit less at starting speed though and the multimeter needs to be in AC mode), but i would assume that the pickup is ok when you see a voltage as soon as the distributor turns.

A a further test: you could switch the red an green wire to the HEI (red on G, green on W). This just changes the polarity of the output signal, it wont break anything. Be aware that with the wrong polarity your timing will be off, so just use this as a functional test of the pickup/HEI Module.

Hey Adrian :)

I just stopped in to post the latest results and saw your reply. I wired the e1280 up and the car still won't fire up. Could be the pickup. The distributor is new (rebuilt) but we all know that sometimes new parts are defective. I'll test the pickup with my meter...got no scope. I almost hope it is the pickup. It's a cheap part and I can't think of anything else it could be.

Where does the pickup get it's ground?

I kept the new dizzy lined up pretty well where the old one was so the timing should be close enough to at least start.

I really appreciate your help.

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Hi Mike,

 

you can test the E12-80 ignition module with the same method (bridging the red and green wire to trigger a spark) to make sure the module itself is ok.

 

The pickup does not require a ground, the induction by the rotating magnetic wheel induces a small voltage which is then supplied to the ignition module via the two wires (red and green). To check the pickup measure the resistance between the (disconnected) red and green wire.

 

good luck,

Adrian

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I'm getting 0 resistance for the pickup, the e1280 terminals, and the HEI terminals.

I dunno... :rolleyes:

 

So you have disconnected the HEI module from the distributor pickup and then measured the resistance (Ω, Ohm setting) between the distributor pickup wires red and green, and got no resistance, correct? Just making sure, as in one of the last postings you were able to measure 1 Volt, was that also with the HEI disconnected?

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So you have disconnected the HEI module from the distributor pickup and then measured the resistance (Ω, Ohm setting) between the distributor pickup wires red and green, and got no resistance, correct? Just making sure, as in one of the last postings you were able to measure 1 Volt, was that also with the HEI disconnected?

Yes I disconnected the HEI and wired the e1280 back in Monday. All continuity tests were done without anything connected.

The 1 volt reading was with the HEI connected and the key turned on. It was done with the meter in DC mode though. I think you said it should be done in AC.

I'm pretty much stumped here. There's obviously something I'm overlooking but I haven't figured it out yet.

But I'm not going back to the points based distributor.

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When you have disconnected everything else, measured the pickup coils resistance via the green and red wire and you don't get a result around 1-2KΩ, then unfortunately your pickup coil is defective.

You might want to check if the red or green wire is broken or disconnected inside the distributor. Sounds like you need to get a new pickup coil, unfortunately.

Edited by vantage
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When you have disconnected everything else, measured the pickup coils resistance via the green and red wire and you don't get a result around 1-2KΩ, then unfortunately your pickup coil is defective.

You might want to check if the red or green wire is broken or disconnected inside the distributor. Sounds like you need to get a new pickup coil, unfortunately.

If I can install a new pickup and solve this I'll be jumping for joy ;)

I don't really know how to get to the pickup but I think there is a writeup here or somewhere on rebuilding a dizzy. Looking at mine it looks like there are just 4 screws and some kind of pin is what it takes to get to the pickup. I've got a new one coming this week.

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