msd 6a fault???

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cudaboy 67

cudaboy 67

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hello there, this one been ongoing, first give brief outline.......car been running bad now for months, only attempt to take out weekends but every time im towing home:cry: was running/starting then fluffy and dies, classic fuel i thought...ive stripped fuel tank,cleaned and lines, had a new fuel pump,did complete carb rebuild then last week ditched my points dizzy to a two wire electronic one, new msd blaster coil etc, re configured the wiring from my msd 6a and away to go! went to start it later in day and no joy,weird. pal came over today, we went thro timing,pullrd some plug leads off have spark.one minuite car doesnt want to start, then when it does its real fluffy and dies after couple minuits. theres good ruel supply, its like its a real weak spark on all 8 and im suspecting the msd.any thoughts?
 
So is this an MSD 6 ignition triggered with a mopar electronic distributor?

If it is - never run a 6a with disconnected plug wires.

You could have just left the point distributor in the engine to trigger the MSD - they work just fine with a points trigger.

.
 
have you checked the pick up coil on the distributor...and check the air gap
 
hello there, brand new dizzy and coil, car started,ran, drove round block, perfect, started car later that day..........perfect. left it a week, wouldnt start.been suggested to buy a ATE 6AL due to so many msd 6al failings? or can i ditch the elec box and put a ballast resisistor in there and run coil+ to batt....but then theres two wires to dizzy..........hmmmm.
 
I have had 6a ignitions outlast cars. I have also seen a cracked coil tower kill 3 of them in a week.

If it ran good, then quit after it sat for a week, start looking for a high tension leak someplace.

Grab a spare plug wire & plug. Ground the plug body, and plug the wire into the coil. Test the ignition. You should have a very hot spark at that plug.

Watch the coil carefully when testing. If it arcs anyplace besides the gap in that plug, you have your leak.

B.
 
hello there, coil brand new, new lead to dizzy, no arcing, plugs still sparking but just not that good, i aint a betting man but if i was my money be on somthing getting warm in msd box and playing silly buggers....
 
hello, theres no real voltage to coil from msd even when car does run, that kinda odd but how it is, im going to check the ign live from keyswitch to msd just in case but its like the car is fluffy and missing yet its not actually missing on one particular plug like down on all of them,like a dimmer switch to plugs and they only operarting on half.
 
cudaboy 67 said:
ign live from keyswitch to msd .
Click to expand...

Exactly what I meant. The "keyswitch" voltage goes through the bulkhead connector. If the circuit path from the battery -- through the bulkhead/ firewall connector -- through the ignition switch and connector -- and back out the bulkhead/ firewall connector -- has a poor connection somewhere, you won't get "good" voltage to the ignition.
 
Ok, so you have a mopar magnetic trigger distributor yes?

The black wire from the distributor is connected to the green wire from the MSD magnetic pickup connector yes?

The orange wire from the distributor is connected to the violet wire from the MSD connector yes?

Nothing else is connected to the pickup wires yes?

The white wire from the MSD box should not be connected to anything, and not grounded either.

The large gauge red wire should be connected to the battery, or the alternator output stud. It must receive constant 12v power, from a circuit capable of 30 amps or more.

The large gauge black wire should be connected to a good ground - it needs to carry 30 amp peak loads too.

The small gauge red wire is connected to the ignition switch. This is the wire that turns the ignition on & off.

The orange wire goes to the positive side of the coil. The small gauge black wire goes to the negative side of the coil.

No other connections go to the coil. There will be no voltage to measure at the coil connections - this is a capacitor discharge system. The red box dumps about 250v into the coil when it is time for a spark.

Again, only the orange & black wires connected to the coil - nothing else. Only the green & violet connected to the distributor magnetic pickup - nothing else.

B.
 
hello, all wiring good as i rewired car, was using the white wire when points dizzy, now using the two wires from mag output,<white disconected> have good connections to constant positive/negative and to coil, i will however be rechecking thr switched 12v ign supply as this the only weak link before i write off the msd unit as faulty.i figured however if i was to lose the 12v ign the car would either start/run or not and not start and run bad like it is, cheers for the input all!
 
hello and thankyou all for the input! ordered new msd streetfire box, before i fitted it i tried to start car one more time with the suspect msd 6a...odd thing but the needle on my aftermarket tacho went all the way to the max and has stayed there:eek:ops:<worked fine before> was this the msd last act of defiance before being removed and chucked for a younger sleeker model :tonqe: anyhow, it was removed and streetfire fitted, car now idles <have to sort timing again> has lost its lumpyness and is back to where it should be. :cheers: so many folk have said an msd will either work or it wont, mine running bad the exception!
 
Which blaster coil are you using?

Regular round oil filled style or the new Solid State SS Coil?
 
hello, i bought the coil new with the dizzy from hauser racing here in the uk, i said my intended aplication and told the coil matches the dizzy and will work with the mds settup, i imagine its the sold state, it says blaster 2 on side.
 
I had problem with msd 6al I did some of the same things you did tracking fuel problems I even had their pro billet distributor and msd coil. I canned the whole msd system went back to mopar setup, 2 years later no more ignition problems. Msd will repair the unit but for a price plus shipping. Google MSD problems you can see for yourself these things are far from bullet proof.
 
hi there, cheers for the info, real threw me a curve ball, classic fuel type probs and the msd was the last thing to replace :violent1: never mind i got new coil,dizzy,rebuilt carb,new fuel pump,cleaned out tank and lines.......hee hee,keeping my original points dizzy so if i ever do get caught out can swap over on side of road with a little wiring and ill always get me home!
 
cudaboy 67 said:
hello, i bought the coil new with the dizzy from hauser racing here in the uk, i said my intended aplication and told the coil matches the dizzy and will work with the mds settup, i imagine its the sold state, it says blaster 2 on side.
Click to expand...

The Solid State coils look like a square-ish box. Does yours look like that?
 
daredevil said:
msd= might suddenly die
Click to expand...

That applied to every electronic ignition out there. There are plenty of chebby guys that carry a spare HEI module & the tools to change it in the glovebox. I have watched a friend replace 2 of those in the past couple of years in his daily driver.

I have had ford OEM TFI units die, with no warning - just a failure to start. Usually at about 60k miles. The older duraspark was the same way.

Mopar orange box/chrome box/blue box etc. mag triggered ignitions die as well.

Since the MSD 6 series has been in production for decades (there is a 40th anniversary model) and it has been fitted to all makes & models - there is every chance that there are more of them made / in service than the mopar box. There are a lot of them out there. Some will fail. The percentage is very low.

All electronic ignitions can fail. I had a Pertronix that almost caused me to replace a damper - the timing would drift over 30 degrees while you watched the timing light. Glad to see the OP got it sorted out.

If you want an ignition that fails slowly - stay with Kettering's points. Of course you have to maintain them, and they can't give you that powerful spark CDI can. But they are dependably mediocre.

B.
 
MSD..might suddenly die. Now that is clever. Points will get you home, keep one in your trunk. I had an MSD fail, brought points out and got it home. Put MSD back in again, drove around, failed again, had points in trunk this time. Got me home. Installed old Mallory Hyfire5, have not touched it since. still carry the points in the trunk.
 
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