No spark to left bank (1 3 5 7)
 

OK, I haven't driven my truck since early October until a couple weeks ago. When I finally got it out, the battery went dead. I jumped it off and got it running. Drove into town, got a little gas, then took it by the parts store to test the battery. The test showed the starter and alternator was good, but the battery was weak. After leaving the from the store the engine was running very poorly. Would barely run, idle, etc. I limped it home, hooked up the Battery Tender and haven't messed with it until Friday when it still had all the same symptoms. I checked the headers with an infared thermometer and noticed the driver's side(1 3 5 7) were still cold. I'm going to start with checking grounds and check for voltage at the coils, but I'm worried the charging test may have fried my MSD box since that's when the problem started. Or could the weak battery just be causing the MSD to work improperly? Anyone else have any ideas?

I've seen two cars do this due to a bad coil ground.

I haven't had time to mess with it with my hectic schedule, but I plan to recheck all grounds. The only thing I've done for now is unhook the battery. I'm kinda hoping the MSD box will "reset" if the battery is unhooked. I know it's unlikely, but I've seen stranger things happen. LOL

12 Dec update. After leaving the battery unhooked for a couple days, I checked grounds, all were good. I charged the Optima yellow top from my wife's Mustang, hooked it up and checked voltage. A full 12.3xx to the main hot(pink) wire of the coil harness. Hit the key and she fired right up hitting on all 8 now.

I guess the big question now is, did unhooking the battery for the MSD box to "reset" fix it, or did the fully charged battery solve the issue? Either way, it looks as if a new battery will be my next purchase.

I would say the battery, voltages are critical to the ECM.

I don't think a weak battery would cause one bank to fizzle and let the other one run without a bad connection somewhere or a basic fault, even if temporary. I think the hard reset on the box fixed it. And of course a good battery

Worst case answer is moving the wires caused a loose connection to work again....

Good point

I'm still having the issue. I can unhook the battery for a couple hours and it works when hooked back up. But later, it goes back to losing fire on the left bank again! I'm going to hook the laptop to it to see if I'm getting an error code. I'm really getting frustrated with this 6014 box!

I'm starting to think its the box. If after running a while after re-hooking the battery, I wonder if there's a connection in the box that's getting too warm or just hot.

It sounds like a bad ground to me. Make sure you have a dedicated ground going to one of the heads where the ground cable for the box hooks straight from the battery.. Then a jumper to the other head. The 6014 has 2 grounds for the coil harnesses. Each one is to be hooked to each head. If you have a bad ground it will still search for the nearest ground and could be getting whatever is making the ground get hot and loose connection. We use stainless star washers on all grounds to make sure they are biting good. Something to try real quick.

When I first installed the box, I mounted both grounds together on the back of the block and had the dreaded "cam sensor fault" code. I went through and rewired all my grounds making sure I had the box grounded directly to the battery and each coil ground to the back of each head with star washers for adequate bite. Although none of this fixed the cam fault issue, it's at least grounded correctly. I've not had any issues like this until the battery went dead and the charging system test was administered. I'm starting to think the test messed up something in the box.

I drove the truck to work today while the laptop was hooked up. So far, it worked perfect, but I'll drive to lunch and back then back home after work and keep an eye on the computer to see if anything happens and gives me a fault code.

Post-lunch break update:Everything worked fine leaving work going to lunch. Parked the truck. Went to fire it back up and same thing, no fire to the odd side. Laptop was hooked up and reading, but showing no error codes. I called MSD again. Brett said it's either in the harness or the box, but since it works temporarily, it's most likely the box being bad. I've got to call him back later with a purchase receipt and see if we can get some sort of warranty deal going.

Post Christmas update- I finally got a hold of someone at MSD to talk to a manager. He said evn though it's a few months out of warranty, they will warranty out the box pending inspection. So, the box is on it's way today back to MSD. Hopefully it acts the same for them and I get a new one.

New year, same problems!!! So, MSD warrantied the box and I received the new one Friday. I was busy working a hockey tournament this weekend, so didn't get a chance to mess with it until this morning. I mounted the box and loaded my timing curve before leaving for work. It started up and seemed to be working good. I shut it off and started several times and seemed good to go. I shut it off, went inside and put away all the critters and turned lights off to leave for the day. Jumped in the truck to drive to work, started it and started pulling out of the garage and noticed that sluggish throttle response again. Checked the headers with the infared and, yet again, no fire on the driver's side bank!!! I'm about ready to set this thing on fire and collect the insurance money!!!

I guess my next step is start adding grounds. Since the heads and block are aluminum, I'm going to ground the block and each head to each side of the frame and the body and add grounds on the crossmember to each frame rail. I honestly don't think grounds are the issue since it's worked fine for over a year, Since they sent new wiring as well, I may even re-wire the system to see if it's a wiring issue.

My two cents. Is it possible the ECM went bad? When you unhook the battery and hook it back up the ECM is resetting and working for a while. I dont know how you can check it other than replacing it and then if that doesn't work it would suck.

The MSD 6014 is basically the ECM. I just replaced it with a new one and it's still doing the same thing.

I'll be selling my setup soon and going EFI also. I'm in the process of removing the old harness, just been extremely busy with work and family stuff.

OK, I've been extrememly busy the past few weeks, but I finally finished the harness swap. I added a few extra grounds just to make sure that wasn't an issue. One place I added grounds was a strap from each head to the frame rails where the coil grounds are attached. Since the block and heads are aluminum, they don't conduct electricity as well, so I figured this was a safe bet.

The engine is running fine, now. I'm not really sure what went bad in the wiring harness. I inspected it for anything out of sorts, but didn't see anything. I didn't bother checking resistance in anything either, but may still do that if I have any free time, which may not be anytime soon. lol

Thanks to all that replied and offered advice and/or helped.