Hemi Swapping a perfectly good 70 Duster
Ended up getting the coil drivers installed last night. It wasn't as time consuming as I thought it would be. Taking the seat out helped make work under the dash easier.
For those not knowing or understanding why I needed to install coil drivers, I thought I'd explain it. I was previously running LS style coils. LS coils are considered "smart" coils, meaning they have their own driver inside them. There are 4 wires for each coil. Power, engine block ground, ECU signal ground, and ECU logic signal to fire the coil. The logic signal from the ECU is 5VDC based upon duty cycle.
The Hemi coil is only 2 wires. Just like your old school canister style coil, it has power on one terminal and a switched ground to make it fire. If you're following along, you will remember the ECU puts out 5VDC. That's not going to work with a 2 wire coil. Keyswtched battery power is applied to one side of the coil. The output from the drivers connect to the other terminal. The drivers I installed essentially convert the 5VDC signal to a ground signal with the same varying duty cycle based upon your settings.
Once I got the drivers installed, it was time to power up the engine for the first time and start checking sensors, coils, and injectors. Since I made the wiring harness exactly the same as the small block, I started with the same tune and just started making changes from there. I figured this would be easier than starting from scratch. So far it looks like everything is working as it should. I only made it through checking about half of the things. All of the injectors fire properly and the water temp, MAP, and TPS are reading correctly based on the tuning software dashboard. I need to pull every coil to test each one individually. I did test #1 coil before heading in for the night and the coil drivers appear to work.
Once I get through all the coils, I'll setup the IAC, then confirm all the analog sensors are really correct, which I'm sure they are. After than, I'll crank the engine over to make sure I'm seeing the crank and cam signal. If all that checks out, it will be time to put the fuel pump relay in and make some noise!
Ended up getting the coil drivers installed last night. It wasn't as time consuming as I thought it would be. Taking the seat out helped make work under the dash easier.
For those not knowing or understanding why I needed to install coil drivers, I thought I'd explain it. I was previously running LS style coils. LS coils are considered "smart" coils, meaning they have their own driver inside them. There are 4 wires for each coil. Power, engine block ground, ECU signal ground, and ECU logic signal to fire the coil. The logic signal from the ECU is 5VDC based upon duty cycle.
The Hemi coil is only 2 wires. Just like your old school canister style coil, it has power on one terminal and a switched ground to make it fire. If you're following along, you will remember the ECU puts out 5VDC. That's not going to work with a 2 wire coil. Keyswtched battery power is applied to one side of the coil. The output from the drivers connect to the other terminal. The drivers I installed essentially convert the 5VDC signal to a ground signal with the same varying duty cycle based upon your settings.
Once I got the drivers installed, it was time to power up the engine for the first time and start checking sensors, coils, and injectors. Since I made the wiring harness exactly the same as the small block, I started with the same tune and just started making changes from there. I figured this would be easier than starting from scratch. So far it looks like everything is working as it should. I only made it through checking about half of the things. All of the injectors fire properly and the water temp, MAP, and TPS are reading correctly based on the tuning software dashboard. I need to pull every coil to test each one individually. I did test #1 coil before heading in for the night and the coil drivers appear to work.
Once I get through all the coils, I'll setup the IAC, then confirm all the analog sensors are really correct, which I'm sure they are. After than, I'll crank the engine over to make sure I'm seeing the crank and cam signal. If all that checks out, it will be time to put the fuel pump relay in and make some noise!