Car surging? possible bad ignition box or coil?

pfordamx · 04-06-2019, 11:59 PM

Took our amx to the track for the first time this year with a new engine but same electronics that were working good last October including distributer and ignition box which is 7al2 and a hvh pro power coil. also same plug wires and were used and the same carburetor from last season. the car fired up and showed no signs of issues in the garage it started well and free revved just fine, so we get to the track we unload drove to tech went smooth, and being a new engine i decided to drive up the return road and see if it felt ok and with a little throttle input and load the car stumbled then spring up and stumbled bouncing the rpm from almost dead to 4000rpm so i turned around and drove back to the pits and after changing the cap rotor sparkplugs, jets , pulling the 2 step chips moving timing unplugging the crank trigger and going back to the distributor ressetting up the carb, we could not make it better. we tried to make to passes and you could ease into it and it would feel ok but fast throttle movement or to aggressive and it would stumble and start bucking again. we have a second 7al2 that were installing tomorrow to check that but i'm open to any and all suggestions.

04-06-2019, 11:59 PM	#1
pfordamx Member Join Date: Sep 2011 Location: Oklahoma City, OK Posts: 214 Likes: 3 Liked 7 Times in 5 Posts	Car surging? possible bad ignition box or coil? Took our amx to the track for the first time this year with a new engine but same electronics that were working good last October including distributer and ignition box which is 7al2 and a hvh pro power coil. also same plug wires and were used and the same carburetor from last season. the car fired up and showed no signs of issues in the garage it started well and free revved just fine, so we get to the track we unload drove to tech went smooth, and being a new engine i decided to drive up the return road and see if it felt ok and with a little throttle input and load the car stumbled then spring up and stumbled bouncing the rpm from almost dead to 4000rpm so i turned around and drove back to the pits and after changing the cap rotor sparkplugs, jets , pulling the 2 step chips moving timing unplugging the crank trigger and going back to the distributor ressetting up the carb, we could not make it better. we tried to make to passes and you could ease into it and it would feel ok but fast throttle movement or to aggressive and it would stumble and start bucking again. we have a second 7al2 that were installing tomorrow to check that but i'm open to any and all suggestions.