Msd no run

i installed my new msd ignition, and the first day it ran like a brand new car.


I did not how ever change the gap on my plugs until yesterday which I changed to .55...

started it up and it ran with no power

pulled over and the plugs looked a little foul, regapped back to .30 and drove a little farther

the car shut down while in second gear while driving

i pulled over and I noticed that one of the plug wires was off of the distributor cap

i plan on changing the plugs now...but what else could be wrong?

 

Did you go with a fat plug wire?

 

Well, that's just a bummer!
I assume you mean a 6a or better MSD box.
All I know about this subject is that my MSD still works great! for a year or so now.
So here's my info, maybe it will help: I bought my MSD box "used". MSD supports all OEM coils, so that's all I have, plain vanilla coil (with internal resistor...bypassed ballast resistor). MSD insists on 8mm silicone wires, so I got some. My plugs are gapped at 0.055".
I did encounter one prob a few months ago. I picked up a miss that you could hang your hat on. I replaced the plugs with the old Autolite OEM plug type (the original owner had Bosch plugs in it, and I left them in it). Th prob went away and it runs as good or better since.
MSD states that their box is HARD on the secondary system ... so good cap, rotor, wires seem to be pretty important.
Hope that helps. Feel free to PM me if you need more info, but I don't know much more than this.

 

i have 7mm wires...is that going to be the prob?

 

Yep MSD says 8 or larger.
MSD makes some nice wires.

 

is there a chance that taking the msd off will not work due to any damage to the wires?

will get 8mm wires, but could the msd be damaged?


irritating this upgrade that stops my well running jeep from running well...

 

took the msd off, and still nothing

here is what I know...12.3 volts at pos of coil

12.3 volts at negative of coil with points open

12.3 votls at points with points open

points look a little charred

replacing the coil, points, condensor tomorrow

rotor cap in good shape

questions on msd are this, it was interesting that the msd ignition was not putting any volts the pos of the coil, only to the distributor...does it feed backwards somehow? key on, msd hooked up, 12.3 volts to the distributor wire, but almost no measurable volts to the pos or negative of the coil...

 

Which ignition box do you have?

 

msd 6a

 

Ok, MSD is off and back to points. What's the dwell? Are the points actually opening when viewing using a remote start button? I'm not thrilled to hear the points are "charred" but it wouldn't slow me down either. Just throwing out info: the MSD only needs the points to act as a switch ... gap/dwell are unimportant, BUT there has to be SOME [functional] gap. If charred, pitted, etc, you may have no real gap.
Unfortunately, I forget a lot these days but, I think mine ran fine with the orig 7mm wires but I did not know their history or condition, so I bought new.

 

When the key is on and the points are closed, you should read 0 volts at the neg term of coil.

 

yes to all of the above...

I knew that the points are acting as a switch, which was kind of the last thing that I thought would be the culprit, but everything up to the points seemed to be okay...The - of coil is 0 when the points are closed, and 12 something when open. I just went ahead and got the 8.5 mm wires, a blaster coil, and am picking up new plugs, points, condensor on Tuesday...

Any chance anyone would measure the + of coil, the - of coil and the white wire going to distributor on their msd? I am curious about the ignition as much as anything else...

On the msd website it mentions troubleshooting the functionality of the ignition box by checking to see if the white wire is sparking...I assume that measuring 12 volts on this wire with the key on, would be the same as getting a spark to ground.

 

I'm sorry, I don't seem to be getting email notices till 3 days late and just tripped over your last post. At present, I don't have time to check the voltages but bottom line is, the points-only system has to work before we can go any further. Feel free to PM me, and I'll check whatever you need as time permits

 

Moving down the line of things to check or replace...

New blaster 2 coil

New points

New condensor

Points opening and closing well with nice blue spark.

Was going to re gap points, but don't have the dwell meter I borrowed from a friend last time, so I actually put the msd back on, since it does not matter what dwell is with msd.

Have spark through coil wire to ground(hell of a spark too) at distributor end of coil wire...

Still no spark at #1 or #2 spark plug wire...

Replacing rotor and distributor cap tomorrow...

New spark plug wires from msd came in, but are not the right wires, and are about half the length of the wires needed...

 

i replaced the cap and rotor, and voila! I jumped it right off.

I then immediately ran into charging issues...The engine would die immediately after turning the headlights on. I knew that it doesn't take nearly as much of a charge on the battery to run as to run headlights. I took the battery to the flaps, and they said that it needed to be charged to be retested as it had a very low reading. I went ahead on a hunch and upgraded the battery and paid for the new one, and had them charge it to see if I would qualify for a warranty refund. It tested bad, and i got a refund. With the new battery, it still wasn't charging. I ordered a new alternator a day ahead of time and took that in to be tested, planning on demanding an exchange no matter the test result, and sure enough the alternator tested bad. I intalled the new alternator, and for two days, I have power, restarts, lights, and everything seems okay...jinx!

 

While old-timey ignitions will run poorly with low voltage, electronic ignitions tend to simply shut off and not work at all. Also, when a plug wire comes loose that secondary voltage WILL make a spark somewhere. If it comes loose at the plug it most likely arcs from wire to the nearest ground, maybe through the insulation. If it comes loose at the cap it'll arc inside the cap to the nearest ground. Some electronic ignitions can be destroyed if you crank the engine without plug wires connected.

Chilly