Topic: Problems with MSD ignition

[1980yota]

Hey guys I have having some problems with my MSD that I need to figure out. First let me give you a background of my truck. I have a 1980 Toyota pickup that I saved from the crusher at a local scrap metal yard. I have had it about 3 years now slowly doing upgrades to it over time as I am a college student for one more semester. I completely rebuilt the engine which is a 22r and while I had the motor out I decided to pull all the factory wiring out, which was not only 30 years old but had more wires that weren't hooked up than where hooked up, and start over with all new wire. This was all done over last Christmas break.

I installed an MSD 6 Offroad box and blaster coil along with a fuel regulator to help on inclines and such. about a month ago I went out to start the truck and it wouldn't start I popped the hood to find my MSD box melted where the constant power wire goes into the box and black goo all over the inner finder where I have it mounted. I could actually pull the melted wire out of the box so I put another fuse in and had 12 volts on the wire. This told me the wire was fine and whatever happened must have happened in the box.

I installed another MSD box this time just a 6A model with the same blaster coil and it worked great. I got in the truck yesterday to start it and it would start again. I feared it was something to do with spark because I could smell gas so I check power to the box, both constant and switched, and I checked the ground. Everything checked good but with the key on I did not have power to the blaster coil which is hooked straight to the MSD box. So does this mean I may have another box bad?

I must note that both of these boxes where used so age could play a role in this but at this point with possibly two down in a month I am wondering if there is something wrong with my wiring. I would think it would run bad or not at all if there was. Both of these problems have seemingly happened overnight where I would drive it to where it sits with no signs of running bad and then next day it wont start. Does anybody have any ideas on what may cause this outside of having to boxes go out? I don't want to put another box on just to have the same thing happen again.

For those that don't want to read all this here are the cliff notes:

1) Gone through possibly 2 MSD boxes (both used) in a month. The first melted the constant power wire inside the box, the second I am not getting 12 volts to the coil.
2) Could there be something with my wiring that would cause this or is this just 2 boxes going out?

Thanks for the help guys.

[chim]

I think the best thing to do would be getting a stock ignition wiring diagram and double checking how you have it wired.. maybe switch back to stock coil since Toyota ignition systems are pretty good and don't seem to benefit from an MSD box... also you can bench test your MSD boxes as well to see if they really are bad.. there are instructions on the MSD website I believe.. or just do a search for "bench testing MSD box"

[2manytoys]

I'm running MSD's on 5 vehicles. All were bought used at swap meets except one. It is the only one that gave me any problems and I will be sending it in for repair. All the others are still going strong after years of use.

Like chim said, bench test it. Very easy to do. If it tests good, ya better recheck your truck wiring. MSD has excellent customer support via phone or e-mail. They also have wiring diagrams on their website.

Make sure you post up what you figure out so others can learn from this too. GOOD LUCK!

[1980yota [OP]]

MSD tech support was less than impressive on the phone. I dont see how my wiring can be wrong or else it wouldnt work at all. Its only like 5 wires. I guess I will do some more digging. I have constant power, switched power, and a good ground at the box but no power to the coil with the key on. The coil is hooked up through the box so in my mind thats all it could be. Cant believe I have gone through 2 of these things in a month.

[emsvitil]

The MSD is hooked up to the coil, so you won't see any 12v power at the coil...............

[crazykooter]

The 1st box melting down sounds more like a failed ground then a bad msd box.   It very well could be the same issue with the second box.  I had a msd 6a in my 82 and it was flawless.
I second bench testing it.  If it test out ok then it would be a good idea to run the grounds to the frame instead of the body.   Also where the 2 wires from the msd go to the wiring harness need to be solid.
Its 2 wires if your running a tach adapter.

[1980yota [OP]]

The 1st box melting down sounds more like a failed ground then a bad msd box.   It very well could be the same issue with the second box.  I had a msd 6a in my 82 and it was flawless.
I second bench testing it.  If it test out ok then it would be a good idea to run the grounds to the frame instead of the body.   Also where the 2 wires from the msd go to the wiring harness need to be solid.
Its 2 wires if your running a tach adapter.

I may have to look into the grounding. I would think a better spot would be on the motor though since its grounded directly to the battery. It should be getting a good ground on the body though, I sanded all the paint away to insure a good connection.

The MSD is hooked up to the coil, so you won't see any 12v power at the coil...............

So instead of running 12v to the coil and triggering the ground the box triggers both? Most factory ignition systems I have worked with the box just triggers the ground.

Thanks again for all the help guys I really appreciate it.

[emsvitil]

http://static.summitracing.com/global/images/instructions/msd-6201_frm29772.pdf