GM HEI: Cheap and Extremely Effective Ignition Upgrade

If it's broken or just needs tweaked

Moderators: Volker_P, tidd650

MHolmes
Posts: 33
Joined: Mon Sep 24, 2012 9:51 am

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby MHolmes » Mon Apr 29, 2013 8:08 pm

Hmm...that could explain it...could this also be symptoms of bad HEI modules?

I will have to investigate tomorrow work stole too much of my soul today to investigate tonight.

Loudhvx
Posts: 37
Joined: Tue Aug 23, 2011 5:51 pm

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby Loudhvx » Mon Apr 29, 2013 9:45 pm

If there was a way for the G terminal to internally get shorted to a 12v source, that might explain it, but the G terminal is a very high-impedance input. I would not expect the G terminal to fail that way.

When you get time, the first thing is to try to isolate the pickup wiring. I realize you have it all soldered up, which makes it difficult to isolate. But based on what I can see of the box, it looks ok inside the box. Maybe the problem is outside the box. I would first look at how you have the pickup wires connected to those two black wires, and if there is anything else connected at those connecting points.

Maybe make a quick sketch of how you have things connected, then post a photo of the sketch.

MHolmes
Posts: 33
Joined: Mon Sep 24, 2012 9:51 am

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby MHolmes » Tue Apr 30, 2013 7:23 pm

hope this is legible

(I left out the tail light as it is not hooked up yet and the neutral safety switch, its hooked up just not in the diagram)

Image

MHolmes
Posts: 33
Joined: Mon Sep 24, 2012 9:51 am

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby MHolmes » Tue Apr 30, 2013 7:30 pm

got some readings as well

pick up coils .539 for both (at the coil plug/connector)

going around the HEI Module IGN OFF

G 72.6 ohm : 0.1v
B .363 ohm
C .364 ohm
W 59 ohm
GRND .7 ohm

HEI Module IGN ON

G ?? : 1.3v (when starter is pushed ~9.9v)
GRND 1.39 ohm

my meter died i'll have to get a replacement battery in the morning

Loudhvx
Posts: 37
Joined: Tue Aug 23, 2011 5:51 pm

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby Loudhvx » Tue Apr 30, 2013 8:21 pm

I will have to look at the diagram when I get home. (My work computer blocks some images.)

If G measures 9v when you press the starter button, then the pickups are likely not grounded, or there is some other wiring issue with the resistors etc. When you say the pickups measure ".539", I assume you mean .539 k ohms. That is 539 ohms., which seems right.

MHolmes
Posts: 33
Joined: Mon Sep 24, 2012 9:51 am

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby MHolmes » Wed May 01, 2013 6:53 pm

thats correct.

I grounded the pickups directly to the chassis still the same.

im getting 1.139 k ohms at G with the IGN ON.

MHolmes
Posts: 33
Joined: Mon Sep 24, 2012 9:51 am

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby MHolmes » Wed May 01, 2013 7:03 pm

ok just wired up the old spark units...normal operation... :evil:

so it has to be something with the HEI wiring/setup

Loudhvx
Posts: 37
Joined: Tue Aug 23, 2011 5:51 pm

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby Loudhvx » Wed May 01, 2013 7:17 pm

The starter solenoid is not actually grounded until the clutch lever is pulled in. That may be a problem since there is a mystery "rectifier" also going to the starter solenoid winding. Without knowing what the "rectifier" is for, or connected to, it's hard to say for sure what is happening with the booster power from the start button.

However, even with 12v on the booster circuit, the G terminal should not be 9.9v. It means the resistors are too low in value or the pickups are not grounded all the way.

It is best to use the same ground for the pickups that you use on the igniters, (as you had it with the black wires spliced onto the pickup wires.)

Have you checked for spark with the booster circuit disabled? Some/most bikes should have spark without the booster. Just disconnecting the wire from the solenoid connection should suffice.

What are the resistor values (or color bands)?

MHolmes
Posts: 33
Joined: Mon Sep 24, 2012 9:51 am

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby MHolmes » Wed May 01, 2013 11:48 pm

The rectifier in the picture is a part of the factory wiring for the neutral safety switch and clutch, it is hooked up properly, I just didn't show the full wiring to save a little time on the diagram.

I unsoldered the black wires for pickup ground and soldered them to a ground wire which a then ran directly to the ground on the battery. I got the same result.

I also swapped out the hei units to make sure they weren't at fault....same results

My resistor colors are orange white gold gold

After work tomorrow I,ll try removing the booster to and see if I have better luck

Loudhvx
Posts: 37
Joined: Tue Aug 23, 2011 5:51 pm

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby Loudhvx » Thu May 02, 2013 11:04 am

MHolmes wrote:My resistor colors are orange white gold gold


That would definitely explain the 9.9v at G.

Orange white gold gold is not correct. That is 3.9 ohms.

They should be orange white red. That is 3.9k ohms, or 3900 ohms.


The other issue with the booster is that it should get no voltage while running. Since there is a safety lockuot on the clutch for the starter, it disables the ground connection for the booster (during normal running). If the bikes other circuits apply voltage to the starter solenoid through that "rectifier", it may alter the dwell on the ignition while running.

One solution would be to bypass the clutch lockout switch by permenently connecting the wires together. This will provide a permanent ground on the solenoid's negative side. This will eliminate any unwanted, stray voltage getting to the booster circuit.

MHolmes
Posts: 33
Joined: Mon Sep 24, 2012 9:51 am

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby MHolmes » Thu May 02, 2013 11:09 pm

Damn it, last time I trust some one at work when it comes to electronics.

Ran out to the shack and put in the proper resistors and all is right in the world again. Now to get this beast started and then tidy up the wiring. Thank you all for your help

canuck1sailor
Posts: 24
Joined: Sun Jul 01, 2012 2:41 pm
Location: Victoria, Canada

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby canuck1sailor » Fri May 03, 2013 6:50 pm

canuck1sailor wrote:Has anyone else had experience with these ignitors? I would be interested to know if they reduce the amount of warm up time needed. On a cold day I need ten minutes, minimum; not that I am in a hurry to run off on a cold engine mind you. I have also found my bike is a lot happier now that I use a battery maintainer, perhaps the battery is just getting old and tired although a load test indicated it's fine.



The link doesn't seem to want to work, it's three posts above anyway.


Thanks
Ed


I just installed the Procom Ignitors and test rode. It's a different bike, warm up now a couple of minutes, she will run with full choke, no stumbling, after a few minutes easing the choke while riding she was good to go. No hic-cups.

Pinhead
Posts: 611
Joined: Thu Jan 04, 2007 2:26 am

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby Pinhead » Mon May 06, 2013 10:45 am

canuck1sailor wrote:I just installed the Procom Ignitors and test rode. It's a different bike, warm up now a couple of minutes, she will run with full choke, no stumbling, after a few minutes easing the choke while riding she was good to go. No hic-cups.


With the HEI on my high-compression 652 engine and 0.080" plug gap, in 50°F weather I start the bike with full-choke -- starting takes <1 revolution; the first compression stroke fires immediately.

I let it run on full choke for 10 or so seconds, and then reduce to half-choke or maybe a bit less.

I take off (doesn't need any more warmup time to be drivable) and then once i get up into second gear I open the choke completely. As long as I don't have to stop within a quarter mile or so, choke is no longer needed. If I have to stop at a stop sign within that distance, choke will probably need to be ~1/3 closed.

SchoolDaGeek
Posts: 147
Joined: Fri Aug 26, 2011 8:36 pm

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby SchoolDaGeek » Tue Jun 18, 2013 9:49 pm

Loudhvx wrote:
MHolmes wrote:My resistor colors are orange white gold gold


That would definitely explain the 9.9v at G.

Orange white gold gold is not correct. That is 3.9 ohms.

They should be orange white red. That is 3.9k ohms, or 3900 ohms.




I will also check my originals if I even have them anymore, but this is good information: "orange white red", it is all put away now for another day, let's see if I can locate the original ones that sent me down the wrong road as well...
Buy New, Wire Right. BNWR. LOL

SchoolDaGeek
Posts: 147
Joined: Fri Aug 26, 2011 8:36 pm

Re: GM HEI: Cheap and Extremely Effective Ignition Upgrade

Postby SchoolDaGeek » Tue Jun 18, 2013 10:47 pm

Volker_P wrote:I agree that most motorcycle work should be done in a padded room. :lol:

As far as I remember the ignition switch contains springs and balls. Nevertheless a good idea to clean off there after 30 years. Especially if you have a suspiciously high charging voltage that even rises if you switch the headlight on or your ignitors just did melt.


I remembered this conversation from way back when Matthew/Masika was telling me about his melted ignitors, that is why I have to go down and go through the harness for him, I really don't have any other explanation for his troubles, I did find one original resistor I was using and it was the proper 3900Ohms (3.9k), orange white red, but on that bike as I have mentioned prior, it had so many carb and rotor isssues that after I had my brother rebuild the carbs and pay handsomely, and buy a new customrewind.com rotor for another $100, I did not need to upgrade the ignition at all...
Buy New, Wire Right. BNWR. LOL


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