Shorting out MSD box

[Pro Street Belvedere]

I have a problem, I drove the car for about 3 months, one day it shuts off, I do all the trouble shooting stuff and find the MSD 6AL is out.......So instead of sending it back & waiting two weeks I buy a new one. Car runs great.....
for about two weeks.

So I send both boxes back, MSD tech says they both have the same problem,
a resistor shorts out. So the tech says that there is a problem on the trigger side (wire coming from the distributor) he says something is shorting the wires and sending a pulse back to the box. I checked all the wiring and it checked out fine. I asked if there should be fuse or resistor between the dist & box....He said no.

Anybody ever see this issue, I got the boxes back from MSD, hooked one up and it runs great (now I'm afraid to drive it...Luckly its winter LOL)
BTW MSD did a great job They repaired both at no charge, just shipping

I want to find a fix, I don't want to get stuck in spring.................

 

[Endangered Species]

What distributor are you running? I would look at every wire running to the MSD and see if something is picking up a voltage spike some how.
Just throwing out ideas

 

[beezee]

I agree with KD,and a good ground from the engine to the body, If doing any welding on the car disconnect the battery as a friends MSD went dead after welding on an exhaust pipe.If your using the white wire to fire the MSD when grounded would stop your engine from running but not hurt anything,if high voltage is applied then this could cause failure.

 

[Pro Street Belvedere]

Stock distributor with electronic points, I looked over all the wiring and all checked out good.......I did run an in line fuse from the main power to the MSD box just in case there was a voltage spike from the alterneter, The tech guy said the problem was not from that side of the box, I put the fuse in just in case.

Just my luck...everyone I asked, no one has ever heard of this problem.

Keep the thoughts coming guys

thanks for your help!!

 

[Revhendo]

How are the engine grounds? I run a couple of 6 gauge wires from the heads to the firewall.

 

[beezee]

Cap and rotor,is it possible to arc to the electronic points in distributer?

 

[Endangered Species]

Electrical problems are a bitch!!! If I have a problem I just start eliminating things and going back to the basics.

Where do you have your MSD Box mounted?

 

[Pro Street Belvedere]

Box is mounted on fender well

 

[beezee]

Very nice...eye candy,did notice the wires bundled together, try to separate them with looms.

 

[Patrick]

When you say electronic points in a stock distributor do you mean like a PETRONIX kit? If so I had 6the same problem your having. All it took to cure mine was to by pass the ballast resistor. The low power was causing my MSD to heat up and fry a resistor. But I wont say it'll fix your problem.

 

[Pro Street Belvedere]

Very nice...eye candy,did notice the wires bundled together, try to separate them with looms.

Thanks for the compliment, looks like you have a nice project coming along.

Thats an old pic I have replaced the wires with Moroso's and used wire seperators.

I do not have a ballast resistor installed.

Keep the Idea's coming guys,

I'm going to install a ground strap from the head to frame......I have a turnbuckle tying down the motor I thought that was enough ground but I'll give a ground strap a try

Butch

 

[696pack]

I have had MANY MSD boxes and I hate them. They are very suseptible to heat and even when installing them inside the cockpit I have have several failures. It used to be that if it failed they would do nothing about it, glad to see they helped you out at no cost.

The only reason I have run them is for the rev limiter exchangable plug in. In the future I will run a upgraded Chrysler box with a seperate rev limiter.

 

[Revhendo]

I have had MANY MSD boxes and I hate them. They are very suseptible to heat and even when installing them inside the cockpit I have have several failures. It used to be that if it failed they would do nothing about it, glad to see they helped you out at no cost.

The only reason I have run them is for the rev limiter exchangable plug in. In the future I will run a upgraded Chrysler box with a seperate rev limiter.

I've heard that for years but personally have never had a problem with one that I didn't cause. The two that I did fry, were fixed with no trauma.

I can't stress grounds enough. I learned my lesson the hard way when I built a big block fuel injected car. I thought the 10 gauge ground that I had run from the block to the frame was enough. So, after replacing the steel braided power steering hose that the motor liked better........

 

[SUPERSTOCKRACER]

move that box to under your dash, use a seperate ground from the msd to the body.
the heat reaks havoc on those msd boxes.

 

[Endangered Species]

I agree with Super Stock Racer, Try moving the box inside under your dash. It might be too close to the coil and the alternator, it might be picking up feed back from one of the two. Not to mention heat is bad for MSD's.

 

[retro]

I have a problem, I drove the car for about 3 months, one day it shuts off, I do all the trouble shooting stuff and find the MSD 6AL is out.......So instead of sending it back & waiting two weeks I buy a new one. Car runs great.....
for about two weeks.

So I send both boxes back, MSD tech says they both have the same problem,
a resistor shorts out. So the tech says that there is a problem on the trigger side (wire coming from the distributor) he says something is shorting the wires and sending a pulse back to the box. I checked all the wiring and it checked out fine. I asked if there should be fuse or resistor between the dist & box....He said no.

Anybody ever see this issue, I got the boxes back from MSD, hooked one up and it runs great (now I'm afraid to drive it...Luckly its winter LOL)
BTW MSD did a great job They repaired both at no charge, just shipping

I want to find a fix, I don't want to get stuck in spring.................

Car ran perfect and then suddenly is began to misfire and then shut off after it was at operating temp for 20-40 minutes.

I had this problem and in my situation it turned out to be the coil that was shorting out the trigger in the box after it became hot. Also I was advised by MSD that I must make certain that if the coil is mounted horizontal , that the positive and negative posts must be on the bottom to ensure the oil is covering them. I changed the coil and all was well since.

 

[696pack]

I just bolded my post stating even when mounted in the cockpit I still had problems. They are just too poorly built in my opinion. Mopar boxes hold up much better and are less expensive.

 

[Endangered Species]

I just bolded my post stating even when mounted in the cockpit I still had problems. They are just too poorly built in my opinion. Mopar boxes hold up much better and are less expensive.

696, I respect your opinion, and I agree there is nothing wrong with the Mopar ignition box.
However MSD is the #1 ignition in the industry, no one even comes close. Look at every form of racing out there and they are all running MSD ignitions.

Our MSD 7AL, which is at least 10 years old, works just fine. (now what our box **** the bed this year)

I'm not saying that they don't go bad, all I'm saying is they are not a POS.

If you're burning up more than one new box then there is a problem somewhere else, it's not in the box.

Pro Street..... What Retro posted is a good place to start.


Kevin

 

[SUPERSTOCKRACER]

MSD when wired properly are hands down the best in the industry. my 7al-2 is 12 years old, my digital 6 is 10 years old and my digital 7's are 5 years old. no issues ever.

 

[696pack]

My problems have not been with just ONE CAR, but with many with MSDs over the years. It is not just me, many of the shops I have worked with complain about the same thing. Yes, MSD has ruled the ignition industry for high performance engines for years and therefore get away with murder with box failures and doing nothing about them. I live in the southwest where the ambient temps are much higher than most places and we do everything to sheild the boxes from the heat but the bottom line is that the Chrysler boxes hold up much better and for 90% of hipo cars they perform great.