One Wire Alternator with MSD Ignition

[65coupe408w]

I am having an issue with my MSD 6BTM. I am currently on my second MSD 6BTM now due to having a faulty one the first time. I cant help but think that this is due to my one wire powermaster alternator. Has anyone ever experienced issues when running and MSD 6 box and a 1 wire alternator?

My battery is trunk mounted and I had the alternator wire running directly to the battery and the MSD power feed of the stater solenoid + post. Charging system seemed to be good but my first MSD seemed to burn up, for lack of a better word. I could tell there was an issue becuase after about 5 minutes of running the tach would start acting erratically and bounce all over the place. Shortly after the car would cut out, the MSD box was really hot to the touch and the car would not start until it cooled.

Since then I have received a new MSD 6BTM and have reinstalled it, this time with the main power feed to the MSD directly from the battery as MSD states in the instructions, but I havent hooked up the alternator cable. With a fully charged battery the car runs perfect no issues with the MSD, rev limiter works correctly and the car seems generally happy. This just leads me to believe that the alternator may be the source of the issue. Does anyone have any input on this? This is the last thing I need to figure out before I can get the car out on the street and start tuning it.

 

[bikefreak600]

check the voltage output of the alternator. if it is normal then no worries. maybe your old box was just bad one. i have used numerous msd boxes with no issues. they would get warm to the touch but never stopped working. the only thing i can think of if the problem was your alternator is the voltage was off. OR your solenoid was disrupting power supply ( maybe its old)?

 

[PoppyMod]

Hi,
I suspect, you have an incorrect wiring issue somewhere. I have run a one wire ALT with a Mallory Hy-Fire (same basic program) without fault in my Etype for a number of years. I had an ALT failure after 8 years of service.
Re-check your MSD wiring. As you know, most all of the CD box mfg's suggest the power supply lead be connected directly to the battery +. I suppose the BAT + side of the solenoid would be OK. So, check for a clean MSD ground. The heat, you are mentioning, is typically a sign of high resistance. Insure, both the battery and engine are well grounded. I like "ribbon" style grounds as they are more efficient ground conductors than stranded cables.
Good luck!

 

[mtaqua]

I have a 1-wire powermaster, and no issues yet. However, only got 400 miles on it due to clutch, TOB, tranny, issues, and now a freeze plug. I do run 1/0 cable up to the front of the car and have a + & - post that I wired my MSD to. Starter gets juice from the same post. My alternator goes to the batt through a mega fuze.

 

[65coupe408w]

Thanks for all th input. What size fuse are you running off the alternator? I think I may add a big one just incase I am getting amperage spikes. I am hoping to take it to be tested tomorrow to confirm its good.

 

[WTFO]

My drinking buddy's 64 Falcon also runs a one wire with MSD 6 Digital and the battery in the trunk. We race it regularly with no issues. His car is set up with a large steel bracket to the driver's side cylinder head for a torque strap which also doubles as the engine ground. What ground is on your block?

 

[67GTFB]

believe WTFO is on the right track here .... don't think the kind of alt (one or ext reg) should make a difference .... what I think is going on is a problem in the ground path return to the battery negative .... the MSD may have gotten hot because it was carrying other load returns to the remote battery .... you need to ensure that the MSD box has its own (heavy guage) wire to the battery and you need to ensure that the ground path for other devices (everything else) doesn't use the MSD wiring as an alternate path for the battery to chassis ground .... I have an MSD 6 box too (but with a PowerMaster with ext reg) and it has its own pair of battery connections right to the battery terminals --- HOWEVER, my mechanic who actually did the install (whilst doing a repower job) made the very strong point to NEVER disconnect the battery neg/ground lead before disconnecting the MSD wires from the battery -- otherwise the MSD becomes the return path for lights, radio, etc (this assumes that the battery pos is still connected) .... if you think about it, without a good solid ground path from the engine and engine compartment to the battery neg, the MSD becomes another path for return current .... well, that's the theory, meaning this is all possible .... so I'd suggest making certain that you have good, heavy duty grounds for the chassis and motor and keep the MSD wiring seprate .... I believe this is discussed in the MSD install instructions too ....
FWIW and HTH .... -- 67GTFB

 

[mtaqua]

I've got a 150 amp fuze.

From my 1/0 welding wire in the trunk it runs to a post in the engine compartment. Everything in the front of the car runs to ground at the post. MSD goes directly to it. Some of the interior stuff goes to bus that goes back to the post. The engine has a 1/0 wire to the block, here the 1/0 branches to each head and the starter mounting bolt. I have not had any issues not grounding directly to the batter, but the 1/0 wire is pretty big.