Super Jet Intermittent spark with MSD TL

[Pablo]

I just installed a double pickup MSD TL this past weekend. Wired up and running fine this weekend. Ran the battery dead. Installed fresh battery today. Was very difficult to start. Finally fired and went to ride...felt like I was running on one cylinder. Confirmed with intermittent spark on front cylinder. Rear cylinder firing regular. When I was setting plugs on head I noted that the brain was chirping with small spark noted at plug when I was dragging it across the plug hole(???). Brain was on and lanyard was installed when this happened, but it was strange nonetheless. By the end of a thousand starts with me checking plug wires were secure and wiring was all connected and grounds were in place I ran the fresh battery dead, so I quit diagnosing. When I quit, both plugs had stopped sparking with engine turning over slower and plugs out. No changes made except battery.

1. Why? Ran fine. Parked it. New battery and now trouble??
2. Causes of intermittent spark? Coil, ground, faulty S/S or TL switch?
3. Will a coil just die on you? I've never seen one just quit. I've never really had one be dead.
3. Will MSD TL stop sparking with low battery voltage (kinda like ATP Flame)?

My coils are grounded individually to one of their own mounting bolts and then a common wire splices both ground leads together and runs to the battery ground. I know the directions say each coil needs to be grounded individually to the motor...am I setting myself up for trouble with my current schematic? I know the mantra is that you can never have too many grounds, but the MSD directions don't call for extra grounds.

[COIL]------(coil mount bolt)---___________(battery ground)
[COIL]------(coil mount bolt)---

 

[Aircraftsalz]

I run mine 1 ground per coil to a center ground stud that I also have my start solenoid grounded there. I have another ground lug 1/4 in bolt.. One 6 ga ground to the starter and another 6 ga from that same stud to battery...

Double check everything, it's normally something very simple..

 

[scotts2t]

First of all, do ground your coils to the motor.

MSD will stop sparking/working when your battery gets so low that starter wont even budge. I was out on the lake and my ski died, hit the start button and nothing. my experience with MSD is that it does not have low voltage issues.

I also had a running on one cylinder problem. it turned out to be a bad trigger wire. oh ya, that stock fuse holder that you get with a new brain is crap. fuse holder delete. it took me a looong time to diagnose.

could possibly be a switch problem but usually either they work or they dont, msd gets power from your switch aswell as the red power cable.

 

[scotts2t]

as for your coils holding residual charge, i dont know. could possibly be a bad coil or 12v charge somehow getting into your coil ground?

 

[Pablo]

I was looking at MSD's pics of the individual coils. Why is one mounting hole brass colored and one silver colored? PN42921

 

[scotts2t]

the brass coloured hole is the hole that requires the ground wire I believe. I have always bolted the coils to a plate back to back and use 4 ground wires lol two for each coil for security.

 

[Pablo]

I did some thread searching and read a post that said if the air gap is diff between the two then it will cause trouble. MSD doesn't say they need to be the same. My air gap is not the same on both pickups (0.080" and 0.065"). I just shot to make sure the gap was within the listed specs for both. Could that be the source of trouble?

 

[Pablo]

Today, I tried trimming back the MSD spark plug wires. The inner core of the MSD wires is a very thing gauge, spiral wound wire with lots of insulation. The wire was black from the tip back to 2". I cut it and scuffed them down to shiny copper on both ends and reinstalled. That by itself did not fix the problem. I know you want as little resistance as possible from the plug wires. I don't have any idea what's a small or large amount. I measured 99 and 105 ohms with my volt meter. Whadya think?


Next, the MSD directions show the grounding leads coming off the coil from the same side as the black wire. I had one coil grounded with the ground lead coming from the orange wire side of the coil. I moved that ground to the black side with both of them spliced together to the negative battery post. In addition, I added an individual ground from each coil (same side - black wire side) to a separate head bolt. I've never run extra grounds. Is it any better to ground to the head versus the cases? I assumed it's the same.

Performance-wise it's the same. It's only hitting on one cylinder. It starts on first bump of the starter now, but only one cylinder is firing??? I'm gonna double check my wiring to and from the coils. If that doesn't fix it I'm going to order two new coils and a fresh set of plug wires. You guys have any other advice?

 

[Waternut]

My old plug wires measure 40k-90k ohms. They obviously aren't great since 10k-15k per foot is normal but they worked fine. It's most likely the trigger or coil. It's possible if one coil wasn't grounded very well, you could've fried it. That might explain why it worked when you first rode it and now it doesn't. If you lay both plugs on the head, does only one plug fire and is it always the same coil even if you swap plugs and wires? Can you jump the green trigger wires together and get a spark on that coil?

 

[Pablo]

I need to take back all the words I've said about MSD customer support. I'm eating alot of crow today. I shot them an email this afternoon about my problems. Within 2 minutes they called me directly instead of email. Gave me some quick direction. I tried a few things and still no changes in my situation. I ohm tested both coils and found both to be fine. I was about to pull the flywheel and check my pickups that I had just installed and confirmed air gap two weeks ago. I shot MSD another email before I did that and within another 2 minutes I had another call. He had me check for the remote chance that I had a bad channel on the brain instead of pulling the flywheel and pickups. He said try this first and then it will nail down the pickup as the culprit. Well, sure as sheeeet, it was a completely bad channel on my brain:dunce:. I can't believe that was the problem. I've never heard of a channel going bad on the brain, just the whole brain being shot. Well, I had assumed that with all my problems and previous troubleshooting it was for sure a bad coil. Too bad for me I didn't call MSD first, because I had just ordered a new coil and was out of riding all last weekend.:thumbsdown: At least I have some backup coils now.

Here's some added info for MSD specs:

Coil ohm test: Orange to Black wire < 0.2 Ohms
Coil tower to ground = 2000 Ohms
MSD plug wires = 40-50 Ohms/12" wire
MSD single pole coils are always to be grounded with the SILVER (or right sided hole with coil tower pointing up) mount boss.

 

[sportfish258]

This should go in a data base for MSD . Thanks for the G-2 pablo ... The devil will come a calling bout some stuff you gots laying around... soon very soon