Odd ignition issue....

[2eighTZ4me]

78 280 - carbed - running MSD6AL with a stock dizzy through a Jacobs coil. Just fired it up after a refresh - ran for about 6 minutes, long enough for me to set the timing, and then quit when I locked the dizzy down in place. I could hear the MSD box shooting random sparks with the car off (but key still in the run position) - and then it just quit making noise altogether. Tested the MSD box by grounding the white wire - got plenty of spark, yet when I spin the motor over - no spark. Like it's not even reading the pulses from the reluctor in the dizzy. Shaft has minimal play. Transistor Ignition box??

 

I had noticed, prior to the refresh, that the tach would jump randomly all over the place while at idle, and you could hear/feel 'misses' in the ignition when the tach needle was bouncing. I was suspicious of that behavior back then as well.

 

This particular MSD box has failed on me twice now. I'm sick of this POS. Maybe I just got a lemon - but that has left a bad taste behind regardless. I'm leaning towards it being the issue now - yet the test shows it is generating spark.

 

From what I've read - the two popular ignition setups are the ZX E12-80 or the Mallory. I would 'like' the Electromotive XDI system - but can't justify a grand on ignition for a car that doesn't get driven a whole lot. 

 

Yes - i'd like to fix the current issue, but my fears of the MSD failing again have overtaken the desire to continue screwing with this setup.

 

Open for suggestions...

 

 

 

 

[madkaw]

I have read a lot of bad poop on the MSD, so sorry to hear about your pain. I will give a shameless plug for my e-12 set-up for sale, it works great!!!!!!!!!!!

 

I don't know about MSD's but from what I have read. I know they are sensitive to voltage issues, so make sure everything relating to charging and grounds is solid.

[Six_Shooter]

It sounds like you're still using the original ignitor to trigger the MSD box? In your situation I would try removing that box and using the magnetic pick up of the MSD directly from the ignitor.

 

The only reason I ever use the stock ignitor/ignition modules is when there is computer controlled spark, which you will not have.

 

Why are you using the MSD box and not just triggering the coil directly from the ignitor? Actually that's another test you can try, bypassing the MSD box.

 

If you find that the MSD box is an issue and you don't want to use another MSD, take a look at the MegaJolt. It's more than just an ignition amplifier, you can set different timing curves and even go DIS with it.

[NewZed]

MSNS stands for Megasquirt and Spark, doesn't it?  Spark control is waiting.

 

As noted, it could be that the MSD box is just doing what it's told to do.  It might be fine.  The tach works off of the trigger, not the Multiple Sparks, I believe.  Bad tach signal means bad trigger activity.

[2eighTZ4me]

Six_Shooter - not sure what you mean by using the original ignitor. I'm using the star wheel/reluctor in the dizzy to trigger spark. Red and green wires. Course - now that you mention it - it's been so long since I wired that thing in - i'll need to go back and find where the red/green from the dizzy go to.

 

I did try bypassing the MSD box and ran straight coil (B/W wire to +, and blue wire to -) and got NO spark either. I have to think it's something in the trigger setup as NewZed stated. I do have a spare distributor, so I may try that this evening.

 

The MegaJolt looks very cool - are you able to trigger from an existing stock distributor setup, or do you HAVE to go crank trigger?

[Six_Shooter]

Ignitor - the little black box on the side of later dizzys, or sometimes a separate box altogether that the reluctor wires attach to, to trigger the coil. It sounds like this is what you're using to trigger the MSD through the white "points" trigger wire.

 

You can bypass this and connect the red and green wires to the magnetic input of the MSD 6AL box, you will have to determine the polarity of the Nissan reluctor though, for it to work correctly. They will usually work ok if connected backwards but work best when the polarity is correct.

 

I haven't personally used a MegaJolt, but I believe it will work with either dizzy or crank trigger. Read up on it to verify.

[2eighTZ4me]

That's what I thought you meant - but the black box is on a 79-81. Mine's a 78 - so that function would probably be handled by the Transistor Ignition unit in the passenger side footwell under the dash. ???   When you say magnetic input of the MSD - is that the green and purple wires coming off the MSD box? I don't have a manual here in front of me.

[NewZed]

I misunderstood which car you were working on.  No MSNS.  I would find out where the green and red wires go first.  Know what you have. Check the tach adapter too, if you have one.  Maybe they go bad.   If you find that you're using the stock ignition module to trigger the MSD box, that would be the most likely problem source and changing the distributor won't fix it.

 

The GM HEI module and the various performance versions will trigger from the 78's stock reluctor (green and red wires).  If you decide to get rid of the MSD box or need to fix the stock module.

 

The MSD instructions are on the internet.

Edited May 19, 2014 by NewZed

[2eighTZ4me]

Sorry NewZed - I have 3 - this is the NA car that I've had for 18 years. Is there a way to test the tach adapter? I doubt that's the culprit though. I will search around for the GM HEI setup and see what all needs to be done to accommodate that....but with GM - I just don't want it to 'shut off' !!! (Bad joke in there...)

 

MegaJolt will ONLY work with a 36-1 trigger wheel. So much for that....

Edited May 19, 2014 by 2eighTZ4me

[Six_Shooter]

I haven't used a dizzy on my car in 5 years, so I don't recall when the changes were, you are thinking right.

Yes, the purple and green wires on the MSD box are what I'm referring to. As said the MSD instructions can be found on the inartweebz, more specifically on the MSD ignition website.

 

I also ran the GM HEI ignition module before I went DIS, only really because I had computer controlled timing and it was the best way to give the ECM I am using the DRP (Distributer Reference Pulse) that it needs. The GM HEI module swapis pretty simple, but unnecessary in your set-up from what I read, the MSD 6AL can do what the GM HEI module will do for you. In your case you would use a 4 wire module, that is literally the 2 wires from the dizzy's reluctor, an ignition source and a trigger to the coil.

 

[2eighTZ4me]

Well howsaboutthat..... I had a spare dizzy and went to put it in. Upon removing the old one, I noticed the sheathing around the red and green wires was melted. Upon closer inspection, it turns out it burned through the green wire jacket all the way down to the copper. It was obviously resting on the header and when the green jacket yielded - it shorted and shut the car down. The new pigtail has been routed far away from the header now. All is well....stupid me.....despicable me......