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Discussion Starter · #1 ·
Finally we got this thing nailed ... Turns out it was the fuel pump all along :~)

A little long ... sorry


My Mach1 351C 4V with complete MSD ignition (right down to the spark plug leads) including "in the cabin" timing control.

This engine has been shutting off, just like I turned off the key for about a year now (occasionally). I changed out the Blaster coil to no avail. I have not changed out the 6AL box (the $200.00 price tag has kept me from using this as a trouble shooting measure)

I am aware these MSD systems are very "power supply sensitive" and require a specific "power supply voltage" in order to function. It is my understanding that if the voltage drops below what is needed, the system will shut down.

I have noticed ... When this problem occurs it is always when the batttery seems to be getting low.

Could it be that my charging system is not working right and once the battery backup has dwindled, I am at risk of low voltage?

Causing the MSD to shut down?

To complicate this I have the battery in the trunk, which my be contributing to the low voltage issue and possibly even a charging problem.

I need some tips here on: If this thinking is correct .... And what to do to rectify the problem.

I'll be glad to supply more info if needed


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Larry Madsen
Las Vegas Nevada



<font size=-1>[ This Message was edited by: MonsterMach on 5/19/02 1:44am ]</font>

<font size=-1>[ This Message was edited by: Monstermach on 7/21/02 9:14am ]</font>
 

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is your power lead(to msd box)connected directly to the solenoid/large bat lead? Are you running underdrive pulleys? is your msd box grounded to the body assuming your batt is grounded directly to chassis. also do you have a good ground strap from eng to chassis. just remember a good ground is important. just my 2 cents chris
 

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If you think/know/assume that you have charging problems, FIX THAT FIRST, then go onto the problem of messing with the MSD.
It's gotta have GOOD/STRONG (clean), voltage source.
Same, same for ground.
You can never install too many grounds on an electrical system.
My .002
 

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One other thing you can try to see if your box is screwed is to go to MSD ignition.com and perform the test to see if yor box is good.It requires shorting two terminals together I think.
Bob
 

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How big of a cable do you have running to your battery? I would think a person should have at least 6 gauge wire, or even 4 gauge for a battery in the trunk. Make sure you've got a good size wire (at LEAST 8 gauge) connecting the alternator to the battery as well. Voltage drop across a wire is directly proportional to it's lenght. Same goes for the MSD box, if you use too small of wire, you could have 14 volts at the fuse panel, but only 12 volts at the ignition box. Bigger wire is always better in high power applications.

If I were you, I'd get a digital voltmeter and check the voltage on the power lead right at your MSD box. Those things are supposed to operate normally clear down to 10 volts. If you've got a good constant minimum of 12 volts to the box and it still shuts off, I'd have to blame the ignition box.
 

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Discussion Starter · #6 ·
#2 wire to the battery in the trunk.

I don't own a volt meter ... may need to put that on my next shopping list
 

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I agree, ground it good, check the charding system, & make sure of your power supply. #2 isn't really large enough. I use #0 or #00, no problems with a 6 or a 7.
 

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I would think 2 gauge would be big enough, as long as the starter doesn't have trouble cranking, 2 gauge should be more than enough to feed the rest of the electrical system (uness you're running a baja lighting array or competition stereo, hehe).
 

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Discussion Starter · #9 ·
I have a nice stereo ... but nothing outrageous ... power amp and bass tube.

Conclusion from folks outside FordMuscle is that I need to go to a bigger Alternator ... move from 61 amp to 100 amp.
 

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Now this is a shot in the dark but it has happened, so stay with me.
Have you ever checked you ignition switch?
with all the power running all the accessories, Fords has been known to corrode the contacts in the switch. Another killer of ignitions is a stack of keys and crap on the ring.
As I said, that is a shot in the dark but it has happened to me , after spending $$$'s on replacement parts and hours of testing.
 

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I would second that ignition switch! I had a 69 Ford 429 wagon that would shut off like that. Drove me nuts. Bad switch and the plug was charred.Found it by jiggling the key and plug.
 

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Discussion Starter · #12 ·
Ignition switch was changed out (with new) when restoration took place back in 97 ... so relatively speaking it is "new" ...

As we all know, that doesn't mean that it couldn't be having a problem though.

I'll proceed considering that as a possible problem.
 

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Another annoying thing that happens is with the ballast resisitor. If they have even a slight crack in the filament, the heat from the power going through it will break contact. And, within seconds, it will make contact again and off you go.
 

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I have an MSD 6AL it has a little black(18ga. I think) wire that when grounded cuts the ignition, its supposed to be a security feature. Maybe that wire has chaffed and is intermitently grounding and causing your problem.
 

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So far the advise here has been correct. I would like to clarify a few points though. Voltage must not drop below 11.5 volts or you will have trouble. The problem is current availability in most cases and not voltage. If your alternator is working then the voltage is fine (assuming the battery is good). When the car gets higher in the rpm range the current draw by the MSD goes way up. At 3000 rpm the 6A can draw 25 Amps or more. To ensure this you need to check a few things. 1. Be absolutely sure the battery to starter relay is good and at least a 4 guage wire. If in doubt change it. 2. The 12V feed to the MSD should go either to the battery itself or the bat side of of the starter relay. A higher output alternator will not fix your problem unless yours is not working correctly or you have too much draw from your stereo components. I would suggest moving your MSD box close to the bat somewhere temporaraly and hook up directly to the bat. If your battery is good and the problem persists, then you have proven the MSD to be good. By the way, I worked for MSD for 3 years in repair department and I can tell you that 95% of the failures resulted in a box that did not work at all. Does the car run rough when the rpm goes up? Does the car shut down at random or at some interval? The only other thing I can suggest is the box is overheating and thermal protect is shuting it down. Hope this helps.
 

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Discussion Starter · #16 ·
Battery is new (within the last year) ... (Marine batter)

Problem does seem to rear it's ugly head as I am accelerating ... RPMs climbing

Car runs great ... until it shuts off


Shut off seems somewhat random ... only does it when it's been up and running for a bit ... never done it before things are up to operating temp ... so to speak.

6AL is in the engine compartment ... pretty much where the battery would normaly sit ... not in a "high heat" environment ... could be moved to better air flow position without too much trouble.

I can say for sure though ... problems seem to occur when battery is somewhat depleted, and this condition seems to happen more often than I would expect.

Could easily test it without the stereo blasting
... in order to reduce draw on the electrical system. (However, in this car it has to be blasting in order to be heard)




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Larry Madsen
Las Vegas Nevada



<font size=-1>[ This Message was edited by: MonsterMach on 5/20/02 1:35pm ]</font>

<font size=-1>[ This Message was edited by: monstermach on 5/20/02 1:37pm ]</font>
 

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In an effort to nic this problem in the a$$ I would try to drive the car for 1 full day without the radio on at all. (you will survive) Heres what Im safely assuming, the MSD is not overheating, the bat is good, and the connections are ok. My next question is when it shuts down how long before you can restart the car? When it does shut down does everything go dead like the lights, radio etc?
 

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Discussion Starter · #18 ·
Nope ... not everything is dead, other things work ... car just won't fire.

Seems once it sits a while ... maybe an hour (give or take a few minutes) ... It will fire back up.

However ... as I said in the beginning, it seems to happen when the battery is discharged and isn't cranking the engine over very well either, so I usually need a "Jump" as well to get it fired up.

I don't drive the car every day ... it's just a "For Fun" ... "Street Worrior" kind of toy ... But, I guess I could force myself to drive the thing on a day when I normally wouldn't ...


Just need to do it when someone is available to come pick my A$$ up if it dies
 

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My car acted like that once... and I could have SWORN it was the MSD box. Turns out, there was a short in my steering column. Sometimes, when the wheel was turned just right, the horn lead would short out, drawing the current from the system, and the MSD wouldn't have enough power, and the engine would cut out. Weird. I had no clue until I connected the wheel position to the engine cut outs... Go figure.

Look for bad connections, shorts, and the ignition switch lead. Also check for good grounds. There could be a loose wire or connection inside the box as well, but you'll have to swap another box onto the car to check that.

MSD has a GOOD repair policy... at least they used to. If you sent them the box, they would fix it for a MAXIMUM charge of $60.

Good Luck!
 

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I was just about to say something about thermal protection, but you beat me to it, hehe. I read on the MSD site that their electronics were supposed to run on a minimum of 10 volts, so that's where I got that number. Also, 25 amps?? Dang, I had no idea that ignition setup could pull that much power, I'm impressed!
 
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