My setup was working great since last summer. All of a sudden, the car randomly studders and a couple of times it lost all power while it fired badly.

I also noticed when it starts studdering, that the RPMs spike to 7000+ RPMs. I didn't know if the spark misfire was the cause of the crazy RPM spike, or if it was the other way around - where the RPM spike causes the engine to misfire.

I replaced the coil, changed the plugs, and I even switched the spark drivers to the VB921's according to the msns-extra site. Using the VB921's to trigger the coil alone could not get the car to turn-over.

I thought this was wierd. Do you think that the VB921's won't trigger if the processor port has to drive both the VB921, and the original LED circuitry?

Has anyone gotten the VB921's to trigger our coil without any other power transistor in-line (ie. mitsu power trans, or crane box)?

Also, to eliminate noise, I want to remove the stock ECU completly from the crank sensor, has anyone successfully done this? If so, what voltage should be applied to the crank sensor and how much current does it draw?

Setup:
v2.2 board.

spark setup = RHS R25,R28 --> driving the VB921 circuit --> Crane Ignition Amplifier --> Stock Coil --> MSD low resistance plug wires - Resistor type Spark Plugs.

I am trying to isolate either the ignition or the crank sensor as the problem. I guess I will connect back up the stock ignition system to see if it helps.