Ignition miss at idle with timing control
Goefi 8 power adder.
400 SBC with blow through supercharger on street car.
Initially I ran an HEI without timing control to get the system running. When I was happy with that I fitted a Summit Racing Magnetic pickup distributor 850050 and Summit CDI 850611K CDI and coil.
Initially engine ran fine but after a few times the engine developed a miss at idle, particularly when it got hot. I replaced the CDI with another Summit CDI and had the same problem. I removed tach but problem persisted. I ran the engine without the CDI and the miss went away. This leads me to believe its a conflict between the Summit CDI and the Fitech device.
Ive gone back to the HEI but would like to be able to run the timing control in the future.
The fitech sends a signal to your CDI box to fire. Have you tried deleting the box and firing the coil directly?
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from my 30 plus years of dealing with and building small blocks supercharged and blown check your plug wires and type of plugs, small blocks are finicky when it has a high voltage CDI, try a auto lite plug,, what wires are you running, what is the resistance per foot, I have had cdi systems throw enough voltage to cause a dc pulse in the wire next to the one that is firing and cause a misfire it may be just a simple wire change I normally use a msd 8.8 or the Taylor pro 10.4 you can also go online and chat with summit tech about the ignition system its obviously from what I have read not the fitech , not the cdi box, so electrically walk through the system you have, cap, rotor, the carbon button in the cap, wires plugs, and problem goes away if you remove the box and you had two boxes on the car, also try the old sparkle check put the car in the garage (if you have one) or someplace really dark and while its running spray water on the wires if you have a leaking wire it will arc, just my 2 cents good luck...
Yes I tried the engine without the CDI and the the problem went away. But as its supercharged I wanted the spark energy.
I had a couple of sets of leads and used the ones with the least resistance, they are spiral core. I can try the sparkle test. I can also try closing the plug gap and other plugs.
When the ign fails it shows it solidly on the tach with the needle suddenly dropping.