90 dpfi crx with a zc swap. Had a shotty mpfi conversion by the previous owner. Bought a brand new mpfi swap harness, as well as an obd1 dizzy and jumper harness.

At first we used an OBD2a b20 dizzy, it threw a cyp code and wouldn't rev up. We replaced the icm and it would occasionally drive. We had enough of the dizzy so we bought the right obd1 zc dizzy and cut the harness and soldered the obd1 plug to it. The car works great now but it still cuts out every few days. Also if you turn the headlights on the tachometer stops working. Any leads of where I should look. Car used to throw a code 9 cyp. Now it doesn't throw any code. It threw an ELD code once as well. It's all very confusing and I hate intermittent problems.