The Exciting World of Electricity! (MSD issues?)

[LILCBRA]

Not really, I just can't come up with a good title and I think I've shared the problem somewhere but I can't find it.

The CliffsNotes version: A while back I took the Cobra out and went to dinner with a friend. After I dropped her off the car just died on me when I was aggressively accelerating down an on-ramp for I75. No warning, no sputtering, just shut off like I turned the key. It restarted after I pulled over, then died again after I tried accelerating again. So I left it on the side of the freeway and went back to pick it up the next morning. It didn't start then either, so it was loaded onto a dolly and hauled home. When I got home I decided to give it a try again and the bastard started right up and drove up the driveway without issue.

It's gotta be some sort of electrical bug somewhere regarding the MSD, but it's obviously intermittent. I checked ground, it was good and tight. So all I could think was the damned box has some sort of issue. Then I remembered when the old analog 6AL was giving me issues (which I think it may have actually been the ground that time, but MSD sent me a new digital 6AL free of charge even though my box was well out of warranty), one of the thing I tried was swapping the magnetic pickup in the distributor. They're essentially Ford distibutors, so I swapped an older magnetic pickup from an old Ford distributor that I had laying around and that's what's been in there until now. Maybe that finally quit? So I ordered a new MSD pick up this week and installed it last night. I'm not sure when I'm going to give it a shot again, but fingers crossed that that's it. It might wait until I take possession of the new trailer I ordered the other day, that way if I have to go pick it up on the side of the road I won't have to pay to rent a trailer/dolly again. If that's not it, I guess it'll be back to the drawing board.....

 

[2Blue2]

intermittent pain in the Arse

 

[MustangIIMatt]

MSD: Mostly Starts Dammit!

 

[LILCBRA]

I had to go all Samuel L Jackson with it: motherf'n start dammit!!

 

[Enzio]

I'm sure you know this but the digital msd 6al has a kill switch feature...I think the white wire...that if you're not using it and it happens to touch ground it will die.
The feature is usually fed through a mini switch and run to ground so when it's enabled then the white goes directly to ground. Dead m-f'er.

 

[LILCBRA]

I don't remember the wiring now, but everything looked kosher when I checked it out. There could be a problem somewhere with it, I just didn't see anything.
Waiting until I pick my trailer up to try to take it out and give it a go again. I figure if something like that happens again I won't have to pay a rental fee or pay to have it towed.

I did order a new magnetic pickup and installed that last week. I figure for ~$35 it's not gonna hurt anything, and it could damned well be the issue....

 

[Enzio]

I guess what I was trying to say was if you're not using the kill switch then cover the end with insulation so it won't accidentally ground out and kill.

 

[429MII]

I decided to forgo MSD boxes with my build and went with the Motorcraft Duraspark ignition controller (red insulator), matching ohm coil (special coil) and a Ford duraspark distributor. I think I'm all in for under 80 bucks, and we will see how that works. Took me a while to find USA made stuff but I did. Its cheap enough and I don't hear of many problems with the oem parts, except the occasional bad pickup if offshore made, and a fault with a pick up is easy, either they work or they don't.

I read a interesting thing a while back that the multispark feature of MSD and other brands was actually a fault of the design, and was a work around to get the controller to deliver the desired current without cross firing in a normal distributor cap. It's not any more effective than a single correctly placed large power spark in an engine with a well designed combustion chamber, and a large spaced distributor cap.

The success of the MSD is mainly as a result of the multiple spark process's ability to burn all the fuel in a poorly designed, incorrectly tuned, or over cammed engine, using a regular small cap distributor. (Keep in mind when these things came out there were no large cap distributors.)

Now, the design of the circuitry the motorcraft box uses is a single high current spark which requires a large cap spacing to prevent crossfire. So that is why I thought I would give it a try. In particular, the "red insulator" box was designed with an intensely high current as a way to fire the increasingly lean mixtures common to the emissions era vehicles. These boxes were for California emissions destined vehicles only, and only for a few years. The large cap distributors (duraspark or HEI) are how the large current is able to work without crossfire, so does not require multispark feature. The side benefit to large current spark is the ability to increase plug gap to a certain degree without any detrimental effect. Increased plug gap gives more exposure of the spark kernel to the combustible mixture. It also give the coil more time to recover (more on this below)

The comparison is Its kind of like firing off your combustion with either one .44 magnum shot or an automatic .22 fired multiple times. Both will do the job, but in different ways, and there are reasons for both of course.

Coils have as much to do with high performance ignitions as anything, and are actually the limiting factor to what the box of either type is trying to achieve. The coil needs to be selected based on it's intended usage, and must match the box it is paired with. The OEM's again are always at the leading edge of what works best, and coil on plug is the evolution of overcoming coil saturation, and recovery time problems of single coil ignitions. This is why the single best way to fire an internal combustion engine for years was a Magneto. On a magneto, output current rises with rpm, as opposed to coils which are the opposite, as input voltage remains constant.
The single spark method as Duraspark and HEI use, allows the coil more time to recover and therefore theoretically the coil should be able to continue to produce a decently high output at high rpm. Single fire coils with low ohm resistance, such as the one for the red duraspark box, allow for higher output voltage than a regular coil. Because of this they create a very strong magnetic field and should not be in close proximity to affected electronic components such as electronic fuel injection injectors etc.

As an interesting side note, all magnetic MSD distributors use the Ford pick up. The pick up from my duraspark drops right in an MSD distributor, and vice versa. Seems Ford got ignitions right way back then but didn't capitalize on it.
I also find it interesting that the OEM's (Ford and GM) both went with large cap and high voltage instead of multispark...)

 

[Enzio]

Bump. Did you ever get this worked out? What was the issue?

 

[429MII]

yeah stupid me and my long winded story seems to have stopped the thread lol...

 

[LILCBRA]

No, I've not tried anything with it. I wanted to wait til I picked my new trailer up. Well, I just picked it up today, so it shouldn't be too long before I either confirm or deny whether or not the magnetic pick up was at fault.

Got the new trailer home, unhooked, then took care of a few things around here (mainly cleaned my gutters) before taking a nap.

 

[429MII]

sweet trailer

 

[Enzio]

Wow! nice trailer.

 

[LILCBRA]

Thank you! My next home project requires a bunch of 16 foot 2x4s and a few 12 or 16 foot 2x10s, so it should be put to good use relatively soon. Then I'm going to have to side my house and put up new soffits, so it'll definitely come in handy. The 5-1/2' bed in my truck just won't cut it for that kind of stuff.

Just got back from Harbor Freight and picked up an 8000 lb come along hand winch. I didn't realize the cable was only 10 feet, but it'll serve the purpose in the interim until I pick up an actual winch. I'm eyeing this one off Amazon:

Amazon product ASIN B08GBXPJM7View: https://www.amazon.com/gp/product/B08GBXPJM7?pf_rd_r=32X2WM3GXNN54399WHDP&pf_rd_p=edaba0ee-c2fe-4124-9f5d-b31d6b1bfbee

 

[2Blue2]

Wow, look at that fine trailer! Nice

 

[LILCBRA]

Wow, look at that fine trailer! Nice

And it's already been f'd up!! That's all part of the update.....

So I went to start it but it didn't like it. It kept backfiring though the carb and wouldn't idle. I kept tinkering with the carb and when I was finally able to get it to idle I grabbed my timing light and found I had to readjust it. Once it was warmed up and timed correctly it was off to the races! I took it within about a 5 mile radius and had my buddy on standby in case it died again. Turning the second to last corner about a mile or so from home it just shut down on me again. This time was different though. I lost my AF gauge whereas the last time that was still working. I coasted it to the shoulder, fiddled with some wires, and didn't recover power inside the car, but my electric fan was running. So I start the trek back home, text my buddy an update, and a good samaritan pulls to the side and offers me a ride. He drops me off, I hook my trailer up, my buddy shows up and we're off to load the car onto it. Once I get it home, my options are limited on pulling it up the driveway. I either have to back it all the way down the road, I might get lucky and be able to turn around in a neighbor's driveway, or I pull it straight onto my driveway and pull into the yard to turn it around. I chose the last. Backing it back onto the driveway the trailer jack catches the driveway and jacks that all up (pretty punny, huh? ) but I'm able to back it up onto the garage pad with a little guidance.

Long story short, I didn't completely fix it. I think I might have fixed one issue to only have another one pop up that is very close to the first one. This time, however, I think it's the actual ignition switch. Or a fuse. One of the 2. It's still on the trailer and covered back up though, so for now it's going to remain a mystery......

There was one other thing though. I'm sure it's because it was in the mid 60s as opposed to how warm it was when I tinkered with it the first time, but it has a lean stumble now as well. So I think I might have to tinker with the accelerator pumps and squirter sizes some more too. While cruising at a steady speed it's a tad rich like I set it, but that stumble........

 

[extra_stout]

Aslong as the ignition is not fixed, I wouldn't start to do anything with the carb. If it's running right, it will be solve perhaps also issues like that stumble as well (if it didn't stumble after finishing the tune of the carb when you installed the AFR gauge).
It's mysterious to me that the timing changed that bad, because it's just a year (?) ago that you checked all the ignition stuff.

 

[LILCBRA]

The timing changed because I changed the magnetic pick up in the distributor. That was due to it abruptly shutting down on me while accelerating onto a highway. I didn't lose power to anything other than the ignition system at that time as my AF guage was still lit up. This time, it just shut down AND I lost the AF guage. So I only messed with the carburetor to get it running well enough to test drive it, and the only conclusion I could come up with at the time was that the temperature had changed due to the changing season. When I tuned it it was in the 90s F, yesterday it was in the mid 60s F. Once it was warmed up it ran well EXCEPT the lean stumble (AF guage would jump into the 16s-17s). So, first order of business will be to check my fuses, and if they're good then move to the ignition switch. It's not entirely out of the question that it's bad since it's original to the car. I'm not going to be jumping on any of this right away though, so it'll be a little bit before I update about this again.

 

[2Blue2]

But ran and drove...briefly

and those trailers always seem messed up and now you know why.
First ding always hurts.

 

[LILCBRA]

Pulled the jack off and semi-straightened the mounting location. Then I did some Amazon shopping. I've not pulled the trigger on any of it yet, I might break it up and buy part of it soon and part of it later.