MSefi.com read only forum (Jan.15,2018)

I've had a mysterious problem with a perfectly running tune. I haven't been able to solve this problem on my own for over three years now. The cars runs perfect 50% of the time. When it decides to run perfect it will run perfect for hours. But then sometimes it doesn't (can't detect the pattern). Sometimes when I drive and let it sit for an hour...and the engine will cut out under load in 1st and second gear around 2500 to 4000RPMs for a moment and then starts back up.

The datalog shows that my RPMs are spiking then go to zero.

Some facts about my setup

Car is a 1978 280z Stroker with Low Z injectors (with 6 ohm dropping resisters)
MS 2.2 with 3.0 board (flyback capability connected) with relay board installed.
daughter board installed...only controlling fuel at this point.
Using an ignition module from a 79ZX.
Brand new cap/rotor/wires and plugs.
Grounds are all solid and clean connection running to the engine, batt neg terminal and body is ground to the batt neg term.
Coil has the stock noise capacitor connected
Tach is coming off of the neg coil and is shielded with braided wire and the shielding is ground off.

Attached is the datalog.

thanks for your help

Corey

What exactly is controlling the spark?

The 79ZX ignition module is controlling the spark.

But I think I found the problem. I went through the installation step by step and compared it to the board and found that my board was setup for the Hall/Opto sensor and not the neg coil. (C30 was not installed, D1 was jumpered, D2 was jumpered, C12 was not installed). Lucky for me I ordered those parts years ago and was able to solder them up tonight. I just took it out and it ran smooth. Time will tell...