Good bye coil rail.

[Jim K in PA]

There are two part #s for the 6-tower coil that should work; Airtex 5C1103, which is shown as working in the Dodge pickups and Viper with the V10; and Airtex 5C1432, which shows the same applications as the 1103, plus applications for the Pacifica, Mini-vans, and the 2007-2010 JKs (all V6 powered). Rockauto shows the 5C1103 with a cost of $102.79, and the 5C1432 with a price of $25.99. I have no idea why the wide swing in price, but I suspect that differences in quality may exist . . .

Thought this might help others following along.

Chris - I also read further and saw that you don't have any data to show a difference in mpg, etc. Given that your head did not have the mounting bosses for the later coil rail, I can see the greater motivation for you to ditch the electro-schlong. For my '05 LJ, I am undecided if the conversion is worthwhile.

Jim K

[SilverXJ]

I checked my note book, but I didn't find the pin out in it. I may have wrote it on a separate sheet of paper and I do have one place left to check for that.

So the Viper coil will work and seems to be the only option, but it only solves the installation/removal problem. If one coil fails, the whole unit must still be replaced. I'm not sure if there is enough justification to make this swap. Did you see any improvement in efficiency (power/mpg) with the Viper coil?

I don't have any data for the fuel as you mentioned but it does seem to have a slightly quicker start up and a bit more low end power. Technically the Viper coils does provide a hotter spark. Also, as you pointed out you would have to replace the whole coil if one fails. There is also an advertised hotter replacement for the Viper coil, but I am leery if it is any better.
http://www.performancedistributors.com/ ... nition.htm

There are two part #s for the 6-tower coil that should work; Airtex 5C1103, which is shown as working in the Dodge pickups and Viper with the V10; and Airtex 5C1432, which shows the same applications as the 1103, plus applications for the Pacifica, Mini-vans, and the 2007-2010 JKs (all V6 powered). Rockauto shows the 5C1103 with a cost of $102.79, and the 5C1432 with a price of $25.99. I have no idea why the wide swing in price, but I suspect that differences in quality may exist . . .

Its interesting that there are two coils and they overlap in application. I can' see any physical difference, but it could be something like the one that fits the greater number of applications may have an extra hole someplace. I also don't remember seeing two when I first looked.

Given that your head did not have the mounting bosses for the later coil rail, I can see the greater motivation for you to ditch the electro-schlong. For my '05 LJ, I am undecided if the conversion is worthwhile.

Despite the lack of mounting bosses (which i fixed with some straps) it was still a pain in the ass to get in and out, hindered in proper engine diagnosis on a cylinder by cylinder basis as well as a coil diagnosis. Checking timing using a light was something I couldn't do in the past. The rail is just a shitty design.

I would be interested in your idea of using other coils though. For the reason you stated, individual replacement, and also maybe an even hotter spark.

[ibanezjeepguy]

In theory the rail is a better design because it consolidates the whole ignition system to get rid of the problematic secondary wire first of all.
Otherwise I absolutely love the fact that each cylinders spark plug can be checked at a moments notice to do much needed diagnostics... not to mention the fact of being able to run the older cylinder head

[SilverXJ]

I wouldn't call the ignition wires problematic. They have been in use pretty much since the inception of the ICE in one form or another. I would have liked to go with individual coil on plugs but I don't think that can be done with the stock PCM.

[ibanezjeepguy]

compared to a coil which is relatively reliable the wire is problematic... think of how many cap/rotor/wire sets you replace for every coil.
anyways... totally dig the transformation... and I love plug wires, I put a set of MSD on my Wrangler with the straight six back in 2003 and they haven't even thought about breaking down.
right now from advance auto (where I work) I can get the new coil for $57 vs. $84 for the original style rail.
add in the wires and you definitely come out losing money BUT gain in the long run in terms of making it easier to change plugs, track down misfires, do compression tests, etc. coil on plug could be possible except PCM is setup to do waste spark system so adapting is just a waste, aside from installing a custom setup on the flywheel to trigger an external coil driver..... hmmmm.... waste ? maybe still .......
death to the coil rail !

[SilverXJ]

compared to a coil which is relatively reliable the wire is problematic... think of how many cap/rotor/wire sets you replace for every coil.

I see what you mean now. I wouldn't call it problematic though, just a routine service item like spark plugs and the other parts you mention.

BUT gain in the long run in terms of making it easier to change plugs, track down misfires, do compression tests, etc.

As well as checking timing. I could never get an inductive timing light to work with the coil pack by placing it over (as much as possible) the boot.

coil on plug could be possible except PCM is setup to do waste spark system so adapting is just a waste, aside from installing a custom setup on the flywheel to trigger an external coil driver..... hmmmm.... waste ? maybe still .......

I don't think the PCM would like the absence of coils, it would probably set a code. Then how would the PCM control timing?

[ibanezjeepguy]

PCM controlled timing would definitely NOT work in that case...
you'd be re-engineering a wheel.
someone has replaced the stock coil rail on my WJ so I definitely wont be doing this coil mod personally until either this rail dies or my head cracks and I end up going with the older cylinder head casting

[OBXJ1]

Hey Silver XJ,
Nice job on the Viper coil.
I am planning on doing the same coil upgrade to my 2000 xj.
From your pics It looks to me that you have the front 3 cylinders running on the 6,4,2 sections of the coil. I have one in hand. My understanding is that the 4.0 firing order is 1through 6 firing #1 as the first at the front of the engine. Has someone slipped something in my coffee? THX in advance.

[shawnxj]

do you know off hand if these are logic driven coils or if their high output coil drivers? i'm debating on whether to use a coil like this or ls coils on my megasquirt3

[joshbaker]

hey silver xj, I just attempted thi mod on my 99 wj. I used the 5c1432 coil from rock auto. the coil is labeled 1-6. does it matter which cylinder I put on which post? I hooked them up like you did in your pics. I plugged the harness in just like it was on the coil rail. now the problem is it wont start. it backfired once or twice. kinda reminds me of a dizzy with all the wires in the wrong spot. any help or ideas?

[SilverXJ]

It does matter what plug the leads go to.

If you did the harness side like I did you would just basically extending the stock harness. The plug to the coil appears to be pointing to the driver's side, which is good. Then do as follows: Top posts go to 3 & 4 , middle goes to 2&5, bottom to 1 & 6.

I can't tell what you have going on in that pic but it looks wrong.

[joshbaker]

well, thats the way I have it. my coil says 2&5 top, 4&1 middle 6&3 bottom. I didn't extend the harness, just put the coil where the plug would reach. I just put the stock coil rail back on and its starts, but still has "ignition coil a and b" codes. I might keep tinkering with it tonight. does it matter that I got the cheap coil?

[SilverXJ]

That isn't like the coil used so it may fire different. The one I have crosses over to an Airtex 5C1103, for a 2002 Dodge Viper. Different application and possibly different firing order.

It might be that they just moved the coils a bit. So you may just have to experiment with moving the plugs while keeping 1&6, 2&5 and 3&4 on the same coil. Or the coil pack could be wired internally completely differently. At which point you need to pull the FSM wiring diagrams and your multimeter.

[joshbaker]

just came back in from tinkering. now that I re-read your posts and look at pics, I have mine wrong. I will go out and give it another shot tomorrow. I have 1&2 3&4 5&6 together. now I feel like a dumbass. hope this fixes the problem. thanks for your help, i'll post what happens

[joshbaker]

still no luck. ive moved them all over the place. how do I check them with a multimeter? I don't have a fsm.