I just installed a msd 6al box on my 1980 camaro with hei. as soon as i start the car it backfires out the exhaust! before i installed the msd i adjsut valves and timing on the car and it ran great! Any ideas?

 

Have you gone back through the instructions to ensure it's wired right? Do you have spiral core wires, and NOT solid core? Check your plug gap too; MSD reccommends a .050-.060"" gap so you can't use the plugs as they came out of the box. Make sure it's grounded properly, and go back over the start up list.

 

I went over the list twice. i have a trunk mounted battery so i hooked my positive power to the starter and grounded to the chasis. for 12 volt switched power i just used the wire that was wired into the dizzy under the batt terminal, i checked it does switch on and off with the switch and its getting 12 volts. and the dizzy is getting ground on the header bolt.

 

i just called msd and they said i should have a noise filter installed, and mag pick up wires shouldn't be solidered, they need to be one straight pice of wire so they have a wiring kit. so ordered those to things and i will see. it seems they jus throw parts at you and hope that fixes it.

 

Hope it does!

 

i really dont see how the noise filter would help because it says its made to stop interfeirence with the rado and things like that, not the other way around.

 

The filter doesn't make sense to me either. Filters generally keep the ignition system from emitting RF that causes noise on your radio, not to stop noise on the ignition system.
The soldered wires to the pickup sound like a possible solution, so that part might help. I'd also make sure the grounds are good, and if you're using the starter as a hot, then the block as a ground you should be fine there. Just be sure the block ground path back to the battery is also very good!

 

the filter seems strange, a way to sell more product.

 

John... Did you get everything set good like 69 and I were helping you with on the other threads? Once the static timing is good the addition of the 6A or 6AL box should not make a difference in the timing and cause back firing. Make sure everything else is good first and then hook up the box.

Massey

 

^ Yep, if the engine was running with the old ignition, and the MSD swap was the only thing done, then it's the MSD hookup. But since you said earlier that you were going to adjust the valve lash, I'm more inclined to believe you may have some set too tight. Intake valves that aren't seating will cause blow back out of the carb. Or if your timing is way off, the engine will try to fire before the valves are closed, also causing a pop back or back-fire.