Intermittent misfire

[Bee1971]

I'm running the msd blaster 2. The former coil was just a stock one I added the msd blaster because I put on accel 8.5 mm wires

Can you put the stock coil back on - I would assume it was a 1.4/1.5 OHM Primary resistance inductive coil designed for your points system

You can leave on your Accel wires + Mancini ECU/Ignition Module

Anyways , hopefully you didnt destroy the Chinese ECU running the MSD Blaster 2 or vise versa

The MSD Blaster 2 coil is a low .7 OHM Primary resistance coil designed for CDI Ignition systems

Sometimes they dont mix well with these cheap ECUs/Ignition Modules

Just throw your stock coil back on , keep your ballast resistor hooked up , and get back to us first on how it runs before we make the next move

Peace

 

[RJRENTON]

I'm running the msd blaster 2. The former coil was just a stock one I added the msd blaster because I put on accel 8.5 mm wires

Out of curiosity, why did you change to the MSD blaster coil? The coil has nothing to do with the distribution wires. 8.5mm wires means what? Most people think that the bigger diameter the better. What specifically does the 8.5mm dimension refer to? Is it the diameter of the center conductor (not likely)? Or is the outside DIAMETER of the wire (probably)? The most important factor is, IMO, is the RESISTANCE (measured in Ohms, per a given length, like per foot or per mm) and the conductor material, like copper or copper alloy. Ideally, a copper conductor would have an almost ZERO resistance, allowing full voltage to be delivered to the plugs. The system voltage developed by the coil would determine the insulation value required (higher voltage = thicker insulation) to prevent flashover or insulation breakdown, while delivering the spark energy to the plugs.
It seems the trend is to increase the spark voltage, in search of more HP or faster acceleration or better fuel milage or ???, which seems to overtax the ECU, leading to its failure, or if the ECU survives, distribution wires are increased because of insulation failures. Just like a "Catch 22" scenario or the chicken and the egg story. Does your system need suppression wires? Which compounds the wire type. If ignition noise on your sound system is an issue, why not use resistor spark plugs and zero resistance (copper conductor) silicon insulated wires?
Sometimes, having something on your car, like 8.5mm spark plug wires, MAY make you the winner in the "one-upmanship contest" contest, at least temporarily but are they really necessary? But to each his own volition....
Just my opinion of course.
BOB RENTON

 

[Drew67coronet]

Out of curiosity, why did you change to the MSD blaster coil? The coil has nothing to do with the distribution wires. 8.5mm wires means what? Most people think that the bigger diameter the better. What specifically does the 8.5mm dimension refer to? Is it the diameter of the center conductor (not likely)? Or is the outside DIAMETER of the wire (probably)? The most important factor is, IMO, is the RESISTANCE (measured in Ohms, per a given length, like per foot or per mm) and the conductor material, like copper or copper alloy. Ideally, a copper conductor would have an almost ZERO resistance, allowing full voltage to be delivered to the plugs. The system voltage developed by the coil would determine the insulation value required (higher voltage = thicker insulation) to prevent flashover or insulation breakdown, while delivering the spark energy to the plugs.
It seems the trend is to increase the spark voltage, in search of more HP or faster acceleration or better fuel milage or ???, which seems to overtax the ECU, leading to its failure, or if the ECU survives, distribution wires are increased because of insulation failures. Just like a "Catch 22" scenario or the chicken and the egg story. Does your system need suppression wires? Which compounds the wire type. If ignition noise on your sound system is an issue, why not use resistor spark plugs and zero resistance (copper conductor) silicon insulated wires?
Sometimes, having something on your car, like 8.5mm spark plug wires, MAY make you the winner in the "one-upmanship contest" contest, at least temporarily but are they really necessary? But to each his own volition....
Just my opinion of course.
BOB RENTON

I switched the msd coil simply because my original one was leaking oil out the top of the tower. I had the wires laying around I was just trying to use my inventory up if I had to buy wires I would have went with the stock wires but I decided to use what I had as to save money. Thank you for your input, if there is anything I learned from I'm this it's that simple is the way to go. I am converting back to points ignition.

 

[RJRENTON]

I switched the msd coil simply because my original one was leaking oil out the top of the tower. I had the wires laying around I was just trying to use my inventory up if I had to buy wires I would have went with the stock wires but I decided to use what I had as to save money. Thank you for your input, if there is anything I learned from I'm this it's that simple is the way to go. I am converting back to points ignition.

Drew,
Thanks for the update...
You are correct....sometimes the simple way is the best way to proceed. Best of luck with your ride and as the turnout Seargent on the old TV program HILL STREET BLUES use to say: "lets be CAREFUL out there".....
BOB RENTON

 

[66-67-Belvedere]

Can you put the stock coil back on - I would assume it was a 1.4/1.5 OHM Primary resistance inductive coil designed for your points system

You can leave on your Accel wires + Mancini ECU/Ignition Module

Anyways , hopefully you didnt destroy the Chinese ECU running the MSD Blaster 2 or vise versa

The MSD Blaster 2 coil is a low .7 OHM Primary resistance coil designed for CDI Ignition systems

Sometimes they dont mix well with these cheap ECUs/Ignition Modules

Just throw your stock coil back on , keep your ballast resistor hooked up , and get back to us first on how it runs before we make the next move

Peace

The ECU must be grounded.

 

[RJRENTON]

The ECU must be grounded.

The low resistance primary of the MSD Blaster 2 coil's 0.7 ohm will csuse, roughly, 2x the current flow the ECU's switching transistor must interupt. Likewise, due to the low resistance of the coil, the inductive reactance will cause s higher than normal impressed voltage that the switching transistor must withstand. Usually these often overlooked aspects cause the premature failure of the ECU. One should ask themselves WHY was an out of spec coil (low primary resistance) selected in the first place? Just because an acquaintance suggested a change, is not a valid reason. The ignition system components MUST be coordinated to insure each individual component is operating within the capabilities of each other.....higher coil secondary coil voltage does not equal more horsepower produced, for once the fuel charge is ignited, any additional voltage applied to the plugs has no effect. Just my opinion of course.
BOB RENTON

 

[kbfallon]

Hello all, I recently converted my points ignition to electronic and I've developed a misfire where as the points didn't miss at all I've replaced plugs wires cap rotor ballast resistor, I'm just wondering what I should test next, maybe I have a bad ecu box? I'm scratching my head on this one the box is new but it came from mancini racing along with the distributor and conversion kit.
Thank you all!

Years Past when working on these cars regularly, I used to keep known good electrical parts for testing purposes....actually, i still do. I would check the ECU.

 

[halojumper]

Is there really any benefit to electronic over points ignition? I was told by a buddy it helped with fuel mileage and throttle response but now it just runs like a turd lol im thinking I made a mistake, luckily I have my points distributor readily available for reinstallation

Tony Defeo, uncle Tony's garage you tube. He stated that an electronic ignition had no advantage over a points driven ignition. He says this was proven on a dyno. Electronic ignitions are more of a convenience thing than any appreciable advantage over a points system.

 

[RJRENTON]

Tony Defeo, uncle Tony's garage you tube. He stated that an electronic ignition had no advantage over a points driven ignition. He says this was proven on a dyno. Electronic ignitions are more of a convenience thing than any appreciable advantage over a points system.

Who is Tony an "uncle" of and what are his credentials....just because he is on U tube, qualifies him how? Is a member of SAE? I would be great to see some data to support his claims.....just saying that one way is better than an alternative means nothing.....at least to me.....show us your data.....
BOB RENTON

 

[AJ/FormS]

I like being able to set my timing, and knowing it will never change, and there is no rubbing block to wear off, and no points cam to develop rounded corners, and I like that if the top bushing wears out, I will never know about it. And I like not having to reach over my fat belly twice a year or more, to pull out the points and file them flat, replace the condenser if the points say so, and then put it all back together, adjusting the dwell, and re-timing it. I just want to drive the beast.

So, while there may be no POWER difference between points and electronic , so what! When has that ever mattered to a V8 powered streeter? I mean you only ever go thru the power peak once on the way to 65 mph, and usually the tires are still smoking at the top of first gear. The bulk of the time your engine will be idling along at 2000 to 3500rpm, am I right? You know I am.

But the no-maintenance electronic ignition system, is way beyond points. Yours might have a hic-up, but the intermittent misfire could be anything, including a faulty install.
I've been running electronic since it came out. I said good riddance to points then, and never missed 'em.
Whatever you decide; good luck.

 

[Bee1971]

Tony Defeo, uncle Tony's garage you tube. He stated that an electronic ignition had no advantage over a points driven ignition. He says this was proven on a dyno. Electronic ignitions are more of a convenience thing than any appreciable advantage over a points system.

Not on this dyno - Points where done by 4500/5000 RPMs

Actually it was a great show , and they even ran Chrysler Ignition boxes / ECU s at one point

https://www.motortrendondemand.com/detail/throwing-sparks-the-great-ignition-debate/930794/

 

[Bee1971]

The ECU must be grounded.

Yes , I Know

And it doesn’t really matter , because the original poster gave up without trying to replace anything like the ECU or MSD coil that I mentioned and went back to a points system he said

 

[coloradodave]

Sure it is Don, but how many dead cars owners have been looking for help about why their car is dead in just the last few weeks, while us Dinosaur points guys are out there cruising day after day. I carry a pocket knife, just in case...
View attachment 1002624

Hey, Dad... I can do that too! MSD Pro-Billet electronic distributor, FiTech dual EFI throttle bodies and; best of all, top UP or top DOWN...lol.

 

[Bee1971]

Beautiful car - WOW !!!

 

[Drew67coronet]

Just another update I was curious as to why i had the misfire, I ended up having a faulty distributor pickup, mancini sent me a new one and the car runs fine now. Just letting you know what happened. Tried a good ecu, no change. Tried a different coil no difference. No voltage drops at battery. Coil had good voltage. Good blue spark bit it would zap really good and then cut out for maybe half a sec and start zapping blue again this led me to believe it was something electrical in the distributor. Thank all of you that gave me advice and helped me diagnose the problem. Keep it classic!

 

[Bee1971]

Nice to hear a resolution

 

[Don Frelier]

Now on to the customary burnout...

 

[451Mopar]

Yes, poor quality parts are very common these days. Same thing with most items you buy these days.
I think it's likely the ECU is not working properly. I suggest you see if Mancini will provide a replacement. At one point a few years back I think my brother had three blue ECU's none of which worked well.
Bob is a very intelligent guy, but unfortunately in this case he chose to be critical and not very helpful.

I think Bob (and many Mopar owners) is just frustrated with all the issues with the Mopar ECU. Just do a quick search. I do think they were better back in the 1970's and 1980's, but quality seems to have gotten really bad while prices more than doubled. Not to mention the parts to make the ECU are likely less than $5.

 

[halojumper]

Who is Tony an "uncle" of and what are his credentials....just because he is on U tube, qualifies him how? Is a member of SAE? I would be great to see some data to support his claims.....just saying that one way is better than an alternative means nothing.....at least to me.....show us your data.....
BOB RENTON

Go look up tony defeo. His claim to fame is not being a youtube guy. Do some research and look him up. He's not some youtube know it all. I bet ten bucks he knows a lot more about mopar than you do smart ***

 

[RJRENTON]

Go look up tony defeo. His claim to fame is not being a youtube guy. Do some research and look him up. He's not some youtube know it all. I bet ten bucks he knows a lot more about mopar than you do smart ***

Define "a lot more"... which is like saying: "how high is up"...a dimensionless statment at best. Does he know more than I do? HIGHLY UNLIKELY.....as I'm a member of SAE and have performed many dyno runs on Mopar as well a several different GM engines. PERHAPS, you can share your your knowledge of what this fellow's qualifications are ... and why the defensive attitude? Is he a friend or ?
BOB RENTON