One Cylinder Not Firing

[pawn256]

*******UPDATE*******: The problem is the big black thing at the top of the cylinder, not the plugs/wires/distributor. The black box that sits in the cylinder on top of the spark plug is the iginition coil right? I'm doubting that NAPA will have one for a volvo... any tips as to where I should order one online?


Well, being a 17-year-old, I have to love cars right? Unfortunately since neither of my parents is much of a car person, I am kind of on my own. I drive a '99 S70 GLT w/ 106,000 miles. Because I had never done much on my car, I decided to pull out a spark plug, just so I'de know I was capable of replacing my own. Everything was fine, and I took out a couple of plugs and put them back in snug (without over-tightening, and making sure to label the wires). The problem is that one of the plugs isn't firing (shakey idle, engine shakes when quickly rev'ing between 2-3k, definite reduction in power).

I took out the two spark cords that I had removed earlier. I noticed that if I only removed a particular cord (call it #1) there was no change in engine noise/rattling/idle when I started it. So I figured #1 was not firing. One at a time I took off part of the plastic piece at the end of the cord so that the little wire coil that holds the spark plug was exposed. I set it up about 1cm above the block and briefly ran the engine. #2 sparked the gap easily as soon as I cranked the engine over, but sure enough, I couldn't get #1 to arc the small gap. So at least I ruled out the possiblility that I damaged the plug while removing it.

So my best guess is that there is a short in the wire somewhere, or that when I was taking out the spark cords off I somehow broke something... By the way, the black plastic casing around the sets of wires (about 1 cm diameter) crumbled at the touch. I don't see what I can do from here besides take it to the shop and explain that I don't think this particular cylinder is firing and that I don't think the problem is the plug.

Thanks for taking time to read this!

ANY IDEAS/COMMENTS?

Oh, and how harmful is it to drive with a cylinder not firing?

-pawn256

[matthew1]

In the dark, start the car, lift the hood and look for arcing from wire 1 to any part of the block, or nearby metal. It's probably your wires by the sound of things.

[pfeener]

Go to FCPgroton.com. In the tuneup section you'll see the ignition wire sets. Get the Bougicord brand wires. They are the OEM (original equipment manufacturer) for Volvo wires. Also replace the plugs if they have 30,000 miles or more on them. Get the genuine Volvo plugs.

The wires aren't hard to do, but you'll need to remove the air filter box to get access. Not a hard job, look through some of the previous posts and you'll get the info you need.

[pawn256]

*******UPDATE*******: The problem is the big black thing at the top of the cylinder, not the plugs/wires/distributor. The black box that sits in the cylinder on top of the spark plug is the iginition coil right? I'm doubting that NAPA will have one for a volvo... any tips as to where I should order one online?

Thanks for the tips. Each cylinder has its own ignition coil right? (the big black thing sits on top of the spark plug...)

I will take off an ignition coil that I know works (making sure to label it) and plug it into the ignition wire for the cylinder that is missing. Then I'll check for spark. I'm hoping this will allow me to tell if the problem is the coil or if it is something else like the wire or distributor.

Well wish me luck, I guess auto-repair is all about isolating the problem. Even if it ends up going into the shop, it would be nice to tell them what isn't working, instead of them just replacing my plugs... then distributor... then engine block... then "Whaddya know, it was just the ignition wire".

-pawn256

[pfeener]

Sorry, my bad. I looked at the parts catalog for the wrong year. Yes you are correct. You're on the right track.