Good bye coil rail.
Posted: October 7th, 2011, 6:40 pm
For the past 9 years I have absolutely despised the stock coil rail BS/PIA. I had been researching a way to replace it for a while, but was unsuccessful in finding a solution. If the wrong coil was selected, best case the engine wouldn't start or run correctly. Worst case I would fry the PCM coil drivers. With NAJXA member offroadordnance's help I installed a Dodge Viper coil two weeks ago. He suggested using the Viper coil and he may be offering a kit for this in the future.
Why I wanted to get rid of the coil rail :
1) Its a real pain in the ass to remove that damn rail from under the cruise control cable, throttle cable, TV cable, heater hoses and AC compressor.
2) As I have an earlier head, it doesn't have the bosses to mount the coil rail to as the 0331 head had. I previously had some stainless steel straps securing the rail to the head.
3) It makes diagnosing a cylinder misfire difficult. You can't simply unplug a single plug and see what happens to the engine RPM/Sound.
4) Anything that involved removing a single plug is a PIA because of #1.
5) If I wanted to pull the valve cover I had to remove the coil rail due to #2
6) Perhaps a more powerful coil.
7) God I hate that thing
From what I have found the coil rail is an idea that came over from Mercedes when they acquired Chrysler, as their V12 engines have 4 of these things.
Anyhow. I mounted the coil near the coolant recovery tank using mount fabricated out of 1/8" aluminum. Its secured on the top on the coolant recovery tank bracket and on the bottom on the body side engine bracket. The engine bracket had two free holes which I used.
I used a Summit Racing V8 wire kit which I cut to length. Initially I had a wing style mount coming off the coil pack to mount the wires too, but once I had the Taylor wire clamps installed I found that to be unnecessary. Besides, it looked really odd.
As for plugging the coil into the stock harness, I spent about a hour going over the wiring diagrams and testing the stock coil to see which pin on the connector fired which plugs(the FSM only lists coil #s for the connector diagram). All I needed to do was run the patch cable in a straight through configuration. With a plug I got from offroadordnance I made a patch harness.
I have been running the coil with out a problem for two weeks. Hot idle quality has definitely improved a bit. And WOT seems to have a bit of improvement, but I am unsure... could just be the placebo effect. It was a pretty much uneventful install aside from making the bracket.
Some pics:
Why I wanted to get rid of the coil rail :
1) Its a real pain in the ass to remove that damn rail from under the cruise control cable, throttle cable, TV cable, heater hoses and AC compressor.
2) As I have an earlier head, it doesn't have the bosses to mount the coil rail to as the 0331 head had. I previously had some stainless steel straps securing the rail to the head.
3) It makes diagnosing a cylinder misfire difficult. You can't simply unplug a single plug and see what happens to the engine RPM/Sound.
4) Anything that involved removing a single plug is a PIA because of #1.
5) If I wanted to pull the valve cover I had to remove the coil rail due to #2
6) Perhaps a more powerful coil.
7) God I hate that thing
From what I have found the coil rail is an idea that came over from Mercedes when they acquired Chrysler, as their V12 engines have 4 of these things.
Anyhow. I mounted the coil near the coolant recovery tank using mount fabricated out of 1/8" aluminum. Its secured on the top on the coolant recovery tank bracket and on the bottom on the body side engine bracket. The engine bracket had two free holes which I used.
I used a Summit Racing V8 wire kit which I cut to length. Initially I had a wing style mount coming off the coil pack to mount the wires too, but once I had the Taylor wire clamps installed I found that to be unnecessary. Besides, it looked really odd.
As for plugging the coil into the stock harness, I spent about a hour going over the wiring diagrams and testing the stock coil to see which pin on the connector fired which plugs(the FSM only lists coil #s for the connector diagram). All I needed to do was run the patch cable in a straight through configuration. With a plug I got from offroadordnance I made a patch harness.
I have been running the coil with out a problem for two weeks. Hot idle quality has definitely improved a bit. And WOT seems to have a bit of improvement, but I am unsure... could just be the placebo effect. It was a pretty much uneventful install aside from making the bracket.
Some pics: