Ignition Coil Installation Preparation

[Seriously]

About two weeks ago my car's CEL lit up while I was driving on the highway (with a noticeable decrease in speed), and I took it into the local garage for some servicin'. It came up as "P0300: Multiple Cylinder Misfire". First visit they replaced the spark plugs, second visit it was the wires, and the whole time they told me that it couldn't be the coils. I know I probably should've done the plugs and wires myself, but the recent arctic blast in Jersey wasn't exactly encouraging.

Well after all that the car is still having the same problem, so I've decided to change the ignition coils myself. I've downloaded and read the associated service manual topic, and I think I'm pretty certain about what I need to do. I do have some questions though:

1) Do I have to replace the "coil on plug" boots when replacing the coils themselves?

2) I've been trying to get as much information as I can from the forums, and I remember someone mentioning that they used dielectric grease on the connectors. Is that necessary or is that more of a performance thing?

3) I know I should remove the negative cable from the battery before starting, but is there anything else I need to do beforehand?

4) Am I insane for trying to do this as my first real DIY automotive project? Right now I really just want to get my car working so I can get to work, but I think I also want to learn more about how my car works. I've kinda kept myself ignorant on the topic but I don't think that's a good idea anymore, especially considering that my car just crossed the 60k threshold.

Thanks in advance for any info, this forum has been an awesome resource in diagnosing my car problems.

 

[azeli73]

Before doing the coils check to see that the catalytic converter hasn't gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open. There is a How to on cleaning the EGR here and I recommend doing that.

 

[goldstar]

The use of dielectric grease is not a performance option. It should be part of the regular installation proceedure. When installing a new coil pack, or replacing the spark plug wires, put a light coating of dielectric grease on the coil pack's boss. Do not put grease inside the coil boot of the spark plug wire and do NOT get grease on the contact terminal itself. Then, insert the spark plug wire's terminal into the coil pack by firmly pushing the boot down over the boss.

If you were replacing the wires, which you're not since they've already been changed, you would also coat the inside of the boot at the spark plug end of the wire with dielectric grease, using a toothpick to insure that the grease doesn't get on the contact.

The purpose of the dielectric grease is to prevent sticking of the boots on subsequent removals which could damage or destroy the wires.

One brand/source of dielectric grease is Permatex available at Pep Boys.

 

[Seriously]

Thanks again for all the info guys, I really appreciate it. I undertook my first car project today, and I think it went off great. The car is running smooth now and no CEL. The idle is still a little rough but I think that might be the EGR valve.

I checked the smell of the exhaust and it didn't smell like eggs (but it didn't smell pleasant either). I think my project next weekend will be to try this seafoam stuff that everyone raves about, and maybe I'll investigate cleaning the EGR valve.

This car stuff is kinda fun once you get started =)

 

[goldstar]

Good job. Glad it all worked out well.

 

[Wingman21]

Before doing the coils check to see that the catalytic converter hasn't gone bad. If you smell rotten eggs in the exhaust, your cat converter needs to be replaced. I've also heard in other cases the problems were faulty fuel injectors.

Random misfires that jump around from one cylinder to another (read: P030x codes) also will set a P0300 code. The underlying cause is often a lean fuel condition, which may be due to a vacuum leak in the intake manifold or unmetered air getting past the airflow sensor, or an EGR valve that is stuck open. There is a How to on cleaning the EGR here and I recommend doing that.

Can a bad catalytic converter causes non constant problem? My car has been acting badly recently (flashing CEL + drastic drop in acceleration + shaking), but sometime it goes away and the car drives normally. I dont know the exact CEL code yet.