At worlds end with no spark

[DocMel]

440, mild build. No spark:

This has been an issue since Sept 2015;   I got so fed up with it (and my wife) that the car has sat since.

Some history:  I was running a MSD 6 digital box, MSD blaster 2 coil with a MSD pro billet dizzy. Your basic MSD set up
 
Seemed to run OK for a couple of years,  but my last drive in Sept 2015 it started cutting out.  I barely made it home

In the garage, I had no spark at the plugs, but wet gas on the plugs

Next I did the MSD troubleshooting by the book.  I got a strong spark at the coil lead by jumping the MSD box white wire to ground:  A positive sign that both the box and coil is working    So to me, that left the MSD distributor......  I ditched the distro, thinking the module was shot:  A somewhat fairly common prob with MSD distros.  I didnt have the $$ at the time for a new distro, so I left the car sitting until now

Just got the xtra $$$ and I just installed a new distro.  A summit unit, basically a Mopar Perf knock off.  The wiring is stone cold stupid simple
I am still running the MSD 6 box and blaster coil

-Still no spark at the plugs, but a very strong spark at the coil lead (as just mentioned above IAW the MSD troubleshooting guide) 
-I triple checked all the wiring.  All good.  All grounds, connections, good to go
-Triple checked firing order
-I even tried 12v hot by bypassing the ignition switch in case there was a prob in that circuit)
-To rule out yet again the MSD box, I switched out the MSD box with the one I have on my chevy powered Toyota FJ.  Still no spark at the plugs
-Yep, the distributors shaft is turing when the engine is
-Installed a new MSD coil, even though it checked out OK 

Good solid 13v at the battery

This has to be a very simple prob that I'm just missing the root cause of.  But at the same time it has really turned me off on the hobby over the last few months, (and my wife), considering all the time, labor and money that I have spent so far over the years, just to have this prob come up, something I cant seem to narrow down and figure out

I've left the car to just sit for 5 months now, and this continuing problem sure doesn't motivate to keep the interest going, considering I have basically replaced everything that the problem could be resulting in a no spark at the plugs

Any recommendations are appreciated

[roadman5312]

If you have a strong spark at the coil lead this makes no sense. Spark into cap should equal spark out of plug wires. New distributor equals new cap and rotor.    I'm thinking. Did you try different spark plugs.     Hey Shelby Dogg  jump in here. 

[mopar jack]

Make sure the distributor is indexed to the # 1 plug at top dead center. Then pull #1 plug wire and check for spark, if it's good it should try to start.

[roadman5312]

OK, so your checking the msd box, key on, grounding white wire. But your checking for spark at plugs by cranking engine ? Power to MSD in cranking mode. ??   I would check that.   

[Chryco Psycho]

bad rotor could ground to the dist shaft but this is a very common problem in HEi but not Mopar dist if you ground a spark plug & rank it over you should get spark across the plug  leaving only indexing so make sure the rtor is pointed at #1 wire when the #1 piston is at TDC firing strke & the wires are correct & in the correct rotation CCW

[cudabob496]

big ground straps on engine?

[cudabob496]

there's a mod to the MSD digital box that I had to make.
check with MSD

[734406pk]

The white wire is for point style ignition triggering of the MSD box. Since you're running a magnetic pick up distributor, you should be intermittently shorting together the Violet and Green wires with the key on to trigger the MSD box. Check the MSD website if you need further instructions. Was your car originally equipped with electronic ignition from the factory by chance?

[cudabob496]

The white wire is for point style ignition triggering of the MSD box. Since you're running a magnetic pick up distributor, you should be intermittently shorting together the Violet and Green wires with the key on to trigger the MSD box. Check the MSD website if you need further instructions. Was your car originally equipped with electronic ignition from the factory by chance?

ya, think I ended up cutting the white. The MSD instructions talk about this, I think.

[734406pk]

Yes if the white wire grounds out, there won't be any spark produced. This can be used as a theft deterrent by using a hidden switch. The white wire is not used in a mag pickup application.

[70chall440]

bad rotor could ground to the dist shaft but this is a very common problem in HEi but not Mopar dist if you ground a spark plug & rank it over you should get spark across the plug  leaving only indexing so make sure the rtor is pointed at #1 wire when the #1 piston is at TDC firing strke & the wires are correct & in the correct rotation CCW

  try a new cap and rotor.

[cudabob496]

Actually, I did not cut the large white wire, but there was a small attachment on the side,
that had three little wires in it. That is what needed modification. It was not in the MSD instructions
at the time.

[73restomod]

Out of curiosity did you check to see if distributor hold down is tight. It could have walked itself out of time. Check the bolt, than grab distributor and try to turn. I have seen them bent outta wack enough that the bolt was tight, but wasn't clamping right.

[Strawdawg]

It's pretty hard to have spark at the coil wire and not have spark at the plug wires unless the rotor is shorted out as Chryco stated.

As you stated that you had installed a new distributor, the shorted rotor would be highly unlikely assuming the new distributor came with a new rotor and a new cap and you used them when installing the new distributor.  With the poor quality control of new parts that we so often see these days, all things are possible, but, I would think it is a very small percentage.

If you still have spark at the coil wire when you check it, I think I would pull a plug and a plug wire off another vehicle, remove one of your plug wires and replace it with the borrowed wire and plug and lay this plug on the valve cover so that it is grounded.  Then crank the engine over and watch the gap on the plug laying on the cover to see if it is sparking.

If I did not have spark at the coil wire, I would disconnect the msd box and go to the parts store and buy a cheap mopar box and install it...being sure that I grounded it well to the firewall or some other convenient ground and try that with your new distributor.  At this point, assuming that you do indeed have a good coil wire spark, that should not be required.

Also, I usually pull the distributor out and spin it with my fingers for spark testing to save fouling the plugs with raw gas while troubleshooting if I don't find the problem immediately.  Wet plugs often do not show a spark.

[DocMel]

These are all good points. 

As said, what makes no sense to me,  is if I have a very strong spark at the coil lead, that should transfer to the plugs

Even if the distro is out of time, a spark should be seen at the plugs.  A distro out of time, to me, just means the plugs wont fire in time with the proper compression stroke.  You'd at least get a back fire if plugs were firing with an out of time distro . I have checked both #1 and #8, no spark.  Also no load up or even a hiccup indicating any fire to any of the plugs

Ill triple check all ground straps as well.  That couldn't hurt to check:  Ill install another strap just in case 

I removed all of the factory ignition components when I first installed all of the MSD components about 2 years ago, as they weren't needed

Troubleshooting:  Correct as said:  I didnt catch that in the instructions: The white wire test is not for testing a mag p/u type distro, like the one I am running.  But I did get a good spark at the coil lead by testing that way.  Even so, when I switched with a known and good MSD box off my other vehicle, still no spark while cranking at my plugs on the 440

However, I certianly need to check the proper way for a mag p/u distro, and thats by jumping the violet and green wires thats in the connector that is not used in my application.   Ill do that today for certain and post