: Tuning up the engine.

09-09-09, 09:10 PM
Hey guys, I'm in the process of tuning up my engine (spark plugs, wires, coils) since I just got the car and it has been neglected. I was able to replace the front 4 plugs easily as they are exposed, but the rear plugs (1,3,5,7) seem to be underneath the intake manifold. What I'm asking is, how much needs to be removed to get at these rear plugs? Thanks

09-09-09, 09:28 PM
Just remove the strut tower cross brace. Then remove the ICM (Coils and all) and set it aside. No need to pull the plug wires. Just pull the 4 connectors (2 each side) and the mounting bolts. Be advised that there is a hidden one on the back side that needs the Braille method. After that it is very easy to get to them.

If it is not missing, there is no need to replace the coils.

09-10-09, 12:30 AM
Awesome, thanks! So you're saying there isn't any reason for me to replace the coils?

09-10-09, 07:51 AM
If the engine was not missing on one or more cylinders, there's no reason to suspect a bad coil. While you have the ICM unit apart you should clean everything with contact cleaner (Radio Shack) and if you feel like it, use a digital VOM to check the DC resistance of each coil primary - the 12 volt side. All 4 coils should be within a few Ohms of each other. If one coil is significantly lower or higher than the other 3, replace it. (Aftermarket coils, if any are available, do nothing for you.)

Make sure you use the diagrams to reconnect the plug wires - it's very important - Google "waste spark ignition" to find out why.

Torque the plugs to 13 ft/lb and use a dab of dielectric ignition grease in each spark plug boot tip and coil connector tip. It seals out moisture, but don't get carried away...........

09-10-09, 10:42 AM
Well, I had a flashing service engine light and I found out that Cylinder 2 was misfiring, but I checked the spark plug for that cylinder and it was badly fouled. So I changed it, and it no longer misfired, so I'm not sure if that's the coils causing the bad plug or not.

09-10-09, 11:48 AM
Your original post says the car was neglected. A complete wire-plug change, cleaning of electrical units and connectors, vacuum line check/replacement, and the like is your first line of attack. Probably coolant, too, unless you can absolutely document a proper coolant change within 3 years.

The fouled plug may have been by chance, or more likely, a marginal plug wire or connector - maybe, just maybe a very dirty coil connector area (dirt + moisture = weak spark).

09-10-09, 06:26 PM
I'm not positive the car was neglected, I was just assuming it was judging by how bad the spark plug was in Cylinder 2.