i just installed a 6al ignition system. now it misfires up to 3000rpm when under a load. what causes this?

I've had bad ones, right out of the box before. I've had them go bad all of a sudden without warning after years of good service too. Make sure it is wired correctly and you have a full 12volts(more is better, 13 to 14v) feeding it.

it is almost new, the guy i got it from ran it one weekend. it runs great at an idle and over 2500 rpm. i think it is the spark plug wires, i just noticed they are turning brown at the boots that plug into distibutor. i am going to get some MSD super conductor wires tonight and try it. it is acting like the wires are crossed.

thanks
mike

i just unplug my vacuum advance, and most of the backfiring went away. i still have little bit, but now the car is pinging real bad. Does MSD changing your timing?

no. im drunk )real drunk) but it doestn changer ur timing. ill clear this up tomorrow.

has anyone had a problem with their vaccum advance on an MSD 6AL? I found i had the magnetic pickup wire backwards, i changed them, but it still misses and pops out the exhuast. My cousins 77 with msd has no problems what so ever. abny ideas? thanks

i just installed a 6al ignition system. now it misfires up to 3000rpm when under a load. what causes this?
You wouldn't happen to have the 3000 rpm test chip they come with plugged in?

i have the 6000 chip in. just out of curiousity, i notice the 6000 chip has a 6000 sticker on it. does that mean it is a testing chip?

also i was wondering, could the problem be my distibutor. I have a Proform HEI distributor that i converted to use MSD by removing the 4 pin module and using the 2 magnetic pick up wires. just a thought. i am going to install MSD 8.5 wires on it and put on an accel high performance cap and rotor

The 3000 rpm chip is the test chip.You could stand on the gas pedal and it won't go above 3000rpm. The 6000 rpm chip isnt the test chip. What do you have the timing set at? Make sure the vac. advance is connected to ported vaccum and not manifold vac.

i ahve initial timing at 14 degrees. Yes, i have the vaccum advance hooked up to ported vaccum. The car runs great when i unhook the vaccum advance, i think i am going to look for a msd distributor this weekend at the swap meet.

Yo! I don't have a 6AL, I have a 6A, and it runs perfect with my HEI and vacuum advance setup. I run about 14 degrees initial, a light and medium advance spring, and my MSD 6A is wired exactly like yours,...remove the four pin module, etc,...I DO have an adjustable vacuum advance that is limited, and you may be having problems with overall advance due to excessive centifugal and vacuum advance. Check summitracing.com for an adjustable vacuum advance and a spring kit for your centrifugal advance. Total advance should be about 45-55 degrees. Check this: http://webpages.charter.net/wag1/heiperformancesetup.htm and have fun!! Todd.

i will have to check my springs and hook the timing light up to see the total advance. thanks for help. have u been to the strip yet?

Yo! 81Z28! Naw! Not with my 2.79:1 rear gears! But I RULE northern Colorado on the road! I DO estimate 0-60 in five, and qmile in about 16. At 14.5 mpg avg. I think I'm doing fairly well at this point. More to do, including a 3.23:1 rear gear, possibly 50-75HP of nitrous, and I'm always tuning! GLAD to be of any help!! Todd.