msd ignition problems [Archive] - FSB Forums

: msd ignition problems


3bronco's
01-01-2005, 06:55 PM
hi i have a 78 bronco 351m im runing a msd 6a ignition msd wires msd coil msd conector to the distributor wich is also new but not a msd. No spliced wires 12v switched power to my key with a new ignition switch.Proper ground red power to posative of battery.My problem is it will run for a bit simetimes 5 min sometimes 30 minutes then it just shuts off i go to restart it and it wont turn over .I get a multimeter and test light and im geting 12v to my ignition switch. Im also getting power to the msd box but im getting no power to the coil .So i think its the msd box so i get another one it runs fine for a bit then it does the same thing as the first one ?then i return it and got another msd box.This is my third msd and the same thing what is going on i dont know what it is or what to do and its not a gas problem new tank new fuel pump filter carb and its getting gas.please help me

Sixlitre
01-01-2005, 07:51 PM
My problem is it will run for a bit simetimes 5 min sometimes 30 minutes then it just shuts off i go to restart it and it wont turn over

Won't crank over ? or will turn over but won't start ?

Sixlitre

3bronco's
01-01-2005, 08:18 PM
sorry about my improper wording. it will turn but will not start

Sixlitre
01-01-2005, 08:30 PM
sorry about my improper wording. it will turn but will not start

Okay

a couple of suggestions for you before you buy annudder MSD-6. Did you get the fancy coil to ignition box disconnect/bypass wire ? Disconnect the MSD-6 and run the truck with just the coil for a couple of days.

If everything is fine it's likely the MSD-6 or the 12 volt switched source.

Sixlitre

3bronco's
01-01-2005, 09:39 PM
the wiring harness comes with the msd 6a. I also have the msd blaster coil the truck was doing the same thing on the stock ford ignition system thats why i converted to msd. I dont understand why its still doing this because msd is its own system conected directly to the battery not off any stock wiring harnesses.

Sixlitre
01-01-2005, 10:15 PM
the wiring harness comes with the msd 6a. I also have the msd blaster coil the truck was doing the same thing on the stock ford ignition system thats why i converted to msd. I dont understand why its still doing this because msd is its own system conected directly to the battery not off any stock wiring harnesses.

I'm still suspecting that switched 12 volt source as it's the only common theme in the whole problem, other than a bad ground. Can you try another completely seperate ignition switched 12 volt source ?

Sixlitre

3bronco's
01-01-2005, 11:20 PM
i will try that thank you

3bronco's
01-01-2005, 11:38 PM
when i turn the key the box is geting 12v acording to my multimeter.So my msd has power now i take a test light and i have no power to the coil.Which means its getting no power.When the trucks runing i have power to the box when it shuts off it still shows it has power but not to the coil

Sixlitre
01-01-2005, 11:50 PM
when i turn the key the box is geting 12v acording to my multimeter.So my msd has power now i take a test light and i have no power to the coil.Which means its getting no power.When the trucks runing i have power to the box when it shuts off it still shows it has power but not to the coil

I ain't no expert but I believe there's 2 kinds of switched ignition on power.

There's the "start" power , a momentary, sometimes timered power and then there's the "run" power for after the initial start up.

On a Dodge this makes a world of difference especially on carbed Mopars.

We need someone else diving in here, because I'm running out of ideas for you, not having a great Ford background.

Sixlitre

3bronco's
01-02-2005, 02:28 PM
please help someone

GHOSTRIDER
01-02-2005, 04:40 PM
3....why dont you get with Steve83 or Fireguy....they are the electrik-ul gurus

81Bronk36
01-02-2005, 08:00 PM
I hooked my MSD to a 12vs sourse and it wouldnt start at all because I needed power in start as well. I dont think thats your problem though. are you sure its not fuel thats your problem?? probably not but its worth ruling out.

also if your ground is loose or any of your wires dont have a good connection they could do that same thing.

3bronco's
01-02-2005, 09:19 PM
new gas tank new fuel pump / filter new edelbrock carb full tank and the carbs getting gas.The problem is it will run then just shut off no power to coil .Now it won't start at all .Msd is grounded. The battery has a proper ground to. One to the block and one to the frame.I have power directly to the positive of the battery and switched 12v to the key.When it dies my multimeter says i still have 12v switch power and constant power from the battery.I have no power to the coil from the msd .3 times i have thought it was the msd i put a new one in and it will run for a bit then die again and wont start?

Sixlitre
01-02-2005, 10:25 PM
new gas tank new fuel pump / filter new edelbrock carb full tank and the carbs getting gas.The problem is it will run then just shut off no power to coil .Now it won't start at all .Msd is grounded. The battery has a proper ground to. One to the block and one to the frame.I have power directly to the positive of the battery and switched 12v to the key.When it dies my multimeter says i still have 12v switch power and constant power from the battery.I have no power to the coil from the msd .3 times i have thought it was the msd i put a new one in and it will run for a bit then die again and wont start?

Do you know the MSD units are definately cooked each time ?

Next controller I buy will be the Crane multi-spark unit as my MSD-6 has been in the mail more than under the hood !!!!!!! Still like their coils best though.

Sixlitre

KillerRanger
01-03-2005, 02:48 PM
When this happens, leave the ignition in the run position, pull off and ground your coil wire (to watch for spark), and grab the white wire on the msd.

Tap it to ground. Every time you break the ground connection, (by picking up the white wire) you should have a spark come from the coil wire.

If you don't, you either don't have power to the MSD box (main) or (switched), or a bad ground to the msd.

if it does spark, then your issue isn't with the MSD, it would probably be with the pickup in the dizzy, the coil going bad, or problems with associated wiring. (wiring from the dizzy chaffed and shorting or the like)

Coincidentally, if you read the owners manual, you can use the white wire for theft prevention. With it grounded the MSD won't fire.

edited slightly for clarity

3bronco's
01-03-2005, 09:34 PM
the problem is i have no spark to the coil and acording to the msd wiring diagram ( instructions how to install) it says for my aplication not to hook up the white wire?

fordman300
01-04-2005, 09:42 AM
if youve got power to the msd, no power to the coil, and it did it before you put in the msd then its probably the pickup coil in the dizzy $20 at the zone

KillerRanger
01-04-2005, 12:59 PM
the problem is i have no spark to the coil and acording to the msd wiring diagram ( instructions how to install) it says for my aplication not to hook up the white wire?


correct, you do not hook up the white wire for normal use.

You can use is for diagnostic purposes like I mentioned, and you can also use it as a theft-prevention ignition kill.

With the MSD powered up, if you ground and break the white wire, everytime you break the ground connection from it, it will cause the MSD to fire one discharge.

3bronco's
01-05-2005, 01:55 AM
i put a new distributor cap and rotor and it runs fine now

Sixlitre
01-05-2005, 01:52 PM
Glad to hear that !

Poor MSD is taking the rap this month !

Sixlitre

3bronco's
01-05-2005, 02:20 PM
thanks for all your help guys