Brain trust....How to troubleshoot no spark on a 6AL MSD system

[Mototrig]

I'm supposed to take the family out tomorrow in the boat and no spark. I'm brand new to 6AL ignition. I verified no spark with a plug pulled and grounded. There's a small relay mounted to the transom under the box tied into the 6AL wiring. .....I looked online for a diagram with the relay. Multiple diagrams show up.

I'm getting 3-5# oil pressure while cranking, not sure if that's enough pressure for the oil switch to throw a start signal.

Motor's a carbureted SBC 350, nothing fancy

It ran fine on the trailer a couple of weeks ago. Any help would be appreciated.

 

[bonesfab]

Scratch the white trigger wire to ground and you should get spark

 

[bonesfab]

big red wire should be constant 12v and small red wire should be keyed 12v

 

[Mototrig]

Here's a lousy picture of the relay tied into the ignition.

 

[Mototrig]

Scratch the white trigger wire to ground and you should get spark

big red wire should be constant 12v and small red wire should be keyed 12v

Alright I'm on it.

 

[sintax]

Alright I'm on it.

Bones has it, just had my msd box fail this summer.

Mine has the msd distributor, so I had to pull the coil wire off of the distributor, lay it within reach of something grounded, and jump the trigger wire where the distributor plugs in to the msd unit. You’ll hear it buzz as it arcs.

 

[Blackmagic94]

Throw it in the trash where it belongs lol

 

[sintax]

Throw it in the trash where it belongs lol

Haha trust me. I’m right there with you. Next time it dies that’s where it’s going and I’ll put in a magneto.

 

[Mototrig]

Scratch the white trigger wire to ground and you should get spark

Jumpered the white wire to ground. Still no spark.
The white wire has 12v when ignition is on. Does that sound correct?

 

[Good Stuff]

Rotor is spinning? I ask because a buddy and I spent an hour trying to diagnose an issue on his boat and the gear on the distributor was toast. Finally pulled the cap and gave it a crank and the rotor just bounced a bit. Felt like a stooges episode.

 

[sintax]

Jumpered the white wire to ground. Still no spark

Did you confirm the box is getting power ?

 

[Mototrig]

Did you confirm the box is getting power ?

Yes confirmed power and ground

 

[sintax]

Yes confirmed power and ground

Which distributor are you running, if you have the full MSD setup, with the msd distributer it’s a slightly different test as I mentioned above

But I’m afraid it’s prob shot, they tend to just fail, no warning. Mine actually did lose the tach output before though

 

[Mototrig]

Which distributor are you running, if you have the full MSD setup, with the msd distributer it’s a slightly different test as I mentioned above

But I’m afraid it’s prob shot, they tend to just fail, no warning. Mine actually did lose the tach output before though

Found it.......
Barely pulled on the pickup wires and the orange wire slipped right out.

3 hours of checking and testing.....

My neighbors must hate me tonight. 10:15 and firing up the boat LoL

 

[Mototrig]

Which distributor are you running, if you have the full MSD setup, with the msd distributer it’s a slightly different test as I mentioned above

But I’m afraid it’s prob shot, they tend to just fail, no warning. Mine actually did lose the tach output before though

To answer your question I have the full MSD distributor.

 

[Mototrig]

Throw it in the trash where it belongs lol

Alright knuckleheads you have my attention. Why should I toss this system in the trash? Other than it being complicated LoL

 

[ElAzul]

Alright knuckleheads you have my attention. Why should I toss this system in the trash? Other than it being complicated LoL

MSD=Chinese shit that will leave you stranded

 

[rivermobster]

Alright knuckleheads you have my attention. Why should I toss this system in the trash? Other than it being complicated LoL

MSD is junk, eventually, it will strand you.

2nd, you have a car box in a marine application...

Go with a Pertronix ready to run marine distributor. No box. Less parts to fail. And built in the USA.

 

[Blackmagic94]

Alright knuckleheads you have my attention. Why should I toss this system in the trash? Other than it being complicated LoL

6AL has been known for years for being prone to failures. My cig runs the Hardin marine boxes and my jet runs the new msd marine digital with good results. Don’t run a car box in a boat.

 

[lbhsbz]

Alright knuckleheads you have my attention. Why should I toss this system in the trash? Other than it being complicated LoL

MSD stands for “My Spark Disappeared”

Throw an HEI on it and call it a day.

 

[HST4ME]

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[OLDRAAT]

(M)ight (S)uddenly (Die)
I've installed many DUI marine distributors with good success. Self contained unit and simple.

 

[Husqy510]

They are prone to failure and probably don't offer much upside in your application.

 

[Nordie]

Alright knuckleheads you have my attention. Why should I toss this system in the trash? Other than it being complicated LoL

MSD = My Spark Disappeared

 

[bonesfab]

Jumpered the white wire to ground. Still no spark.
The white wire has 12v when ignition is on. Does that sound correct?

not that I am aware of

 

[bonesfab]

MSD is junk, eventually, it will strand you.

2nd, you have a car box in a marine application...

Go with a Pertronix ready to run marine distributor. No box. Less parts to fail. And built in the USA.

With the finest quality chinese parts.

 

[bonesfab]

Mystical Speed Device.

 

[575cat]

Must Soon Die .

 

[wzuber]

(M)ight (S)uddenly (Die)
I've installed many DUI marine distributors with good success. Self contained unit and simple.

Get the right kinna DUI in yore bote.... the kind that worx.. The USCG approved DUI....set it and forget it. Pertronix units work too.

 

[mash on it]

MSD stands for “My Spark Disappeared”

Throw an HEI on it and call it a day.

Actually, MSD stands for:

Must Stay Dry.

Always float test it.

If it floats, its good, then reinstall.

Dan'l

 

[Mototrig]

Once I found the loose wire I figured this was a waste of a thread......
But I learned something. Thanks Bromigo's for the school lesson. I thought I was hot shit with an MSD box until now

 

[rivermobster]

With the finest quality chinese parts.

Possibly.

I know unlike MSD, I've never had one fail. And I've installed a ton of em.

We had an instance where we didn't want to put points back in some old 4 cyl restore. We took the distributor over to them, and they made a pickup for us.

They have bailed me out a couple of times. I'm a huge fan of their products And their support.

 

[sintax]

Once I found the loose wire I figured this was a waste of a thread......
But I learned something. Thanks Bromigo's for the school lesson. I thought I was hot shit with an MSD box until now

one word of advice I could give, if you plan on keeping the MSD....

go over ALLLL of the wiring, ensure its properly terminated (crimped) with weather proof connectors. The one you have in the pic up there is no good, as you've you found. You'll also want to make sure the power leads are free from corrosion at the connection points as well. The last final word is to buy a spare MSD box and have it on the shelf, because that one WILL fail at some point, and make sure you buy the proper MARINE one.

 

[ToMorrow44]

The last final word is to buy a spare MSD box and have it on the shelf, because that one WILL fail at some point, and make sure you buy the proper MARINE one.

I always keep the spare in the boat lol. And the power leads have a weather pack connector so I can swap out that box in a couple of mins.
That being said, I swapped to a Daytona Sensors box and put the MSD Capacitor in the power leads, no issues

 

[Universal Elements]

If I may make a suggestion. If possible, relocate that box. Having it above the fuel Valve with the wires Rubbing back and forth from wakes might not be a good idea.

 

[SBMech]

SO many haters. I've never had one fail, properly installed. As pointed out, you are using a non-marine unit, not that it makes a huge difference except to the coast guard.

Always install the Capacitor, these boxes die from voltage spikes, poor connections and grounds. It cracks me up, 98% of them look like a 3rd grader with his Dad's crimper installed it....

But hey, blame the part eh?

 

[Racey]

Jumpered the white wire to ground. Still no spark.
The white wire has 12v when ignition is on. Does that sound correct?

It's an internal pull-up on the white wire that holds it to 12v+ with very high impedance, it will show 12v on a meter, but probably can't light an incandescent test light.

This is a standard electronics feature to avoid floating voltages of signal circuits. Basically if the trigger hasn't pulled the wire to ground then it stays at 12v, this makes it very easy for the electronics to determine a valid triggering occurred, otherwise stray voltage will induce into the wire just from being near to other wires, or even radio waves etc.

 

[Mototrig]

It's an internal pull-up on the white wire that holds it to 12v+ with very high impedance, it will show 12v on a meter, but probably can't light an incandescent test light.

This is a standard electronics feature to avoid floating voltages of signal circuits. Basically if the trigger hasn't pulled the wire to ground then it stays at 12v, this makes it very easy for the electronics to determine a valid triggering occurred, otherwise stray voltage will induce into the wire just from being near to other wires, or even radio waves etc.

Good to know. That's above humble my electronics know how

 

[coolchange]

Knew a guy with msd on his street drag car. Ran fine all the time except on the top end at the track.
Hard shift to 4th would jolt the column and trip the left turn indicator on throwing voltage spikes to msd causing miss fire.
95 percent of stuff I see with msd box’s don’t need it.

 

[caribbean20]

Want to make sure that MSD box never fails? Get a spare and throw it in the boat. I had an MSD 6ML fail after about 1 year and bought 2 the next time. That box never failed for 10 years and the spare sat there gathering dust till I sold the boat.

Can’t tell you how many times I’ve bought a spare of something and the original part never failed. It’s only the parts for which I’ve got no spare that fail. Some bastard out there is playing a joke on me I’m convinced.

 

[rrrr]

Found it.......
Barely pulled on the pickup wires and the wire slipped right out.

3 hours of checking and testing.....

My neighbors must hate me tonight. 10:15 and firing up the boat LoL
View attachment 989162

Any wiring on your MSD, distributor, coil, and ignition switch that is crimped like the one that failed needs to be redone, or you'll have more problems in the future. Those cheap automotive terminals have been crimped with a Vatozone crush crimping tool.

That results in a connection that's inadequate for the pounding a boat wiring system takes, and the insulation on the connector has been damaged. It's not a watertight connection, subject to corrosion, and will probably leave you stranded again.

I use Ancor heat shrink adhesive lined connectors and Ancor Marine tinned 105 degree C insulation wire for my boat stuff. The tinned wire resists corrosion way better than bare copper, and the strands are smaller than automotive wire so it has more flexibility.

The insulation on the Ancor connectors is soft, so when its crimped it doesn't damage it. I use Greenlee 45500 calibrated crimpers with machined dies to crimp the connecters, not a Harbor Freight manual pinch deal. They cost $60, a lot less than aggravation you experienced. Once it's crimped, a heat gun shrinks the insulation and activates the adhesive. This is a watertight connection that won't pull out or corrode.

 

[lbhsbz]

SO many haters. I've never had one fail, properly installed. As pointed out, you are using a non-marine unit, not that it makes a huge difference except to the coast guard.

Always install the Capacitor, these boxes die from voltage spikes, poor connections and grounds. It cracks me up, 98% of them look like a 3rd grader with his Dad's crimper installed it....

But hey, blame the part eh?

I had one burn all the insulation off the main power and ground wires connected straight to the battery (per the instructions) starting a small fire. Dead short in the box. Yeah, I blame the part. It was less than a day old. I sent it back to MSD the following week and they called and explained that the wires would need to be replaced and the burned insulation was the cause of my problems. That response is why I’ll never give MSD another penny.