How do you know when you have a bad coil pack?
i have a random cylinder misfiring. I changed the spark plugs last week and have 8mm spark plug wires that i put in about a year ago if even that. next thing to go to is my coil pack. but i dont want to replace it if its good. how do i know if it needs replacing?
Since you don't have your car listed in the profile, I'll try a couple of quick guesses.
If it is new enough to have OBD2, then you probably know which cylinder has the misfire. You could try swapping the wires on the coil pack and see if the misfire moves. If not, then do a compression check. If that's good, I would suspect the injector.
If it DOES move, then you've got a bad wire, or one bad tower on the coil pack. If you could swap another wire in place of it, that would help to narrow it down.
I've only ever seen a coil pack take down both cylinders when it failed. It's outputs are in parallel I believe, so typically both go down.
If it's older, let us know and we'll have to see what else we can figure out. I would check the compression regardless - I got caught on that one last year - replacing parts that weren't broken.
Thanks John for the input.
Sorry I havent been able to get my car in my profile.
but I have a 2000 Sunfire,
2200 engine.
What code is it setting? Is it P0300, or is it for a specific cylinder?
P0300.
im going to replace the front O2 sensor next week and see if that was the problem. if not though, im basicly lost on what to try next besides the coil pack and wires.
if its miss firing then its the coil pack. Anything eleterical goes once not over time. Its like a starter first have problems starting then wont start. replace the pack and it wont happened. if u want to save money go to the junkyard 98 - 01 are the same.
I would pull out the plugs and see how things look. If it's a coil pack failing, then likely only two of the plugs will be fouled. If all 4 are, (or none), then it could be a fuel problem. Your O2 sensor could cause this, but I would have expected it to set a related code. I wouldn't throw money at that just yet.
Does the car generally perform sluggishly, or is this intermittent? What about the gas you put in? Has it only been on this tank? Even a severely clogged fuel filter could potentially cause this problem. I'll try to look in my service manual and re-read that part to see what other ideas GM has to offer...
John
John S wrote:I would pull out the plugs and see how things look. If it's a coil pack failing, then likely only two of the plugs will be fouled. If all 4 are, (or none), then it could be a fuel problem. Your O2 sensor could cause this, but I would have expected it to set a related code. I wouldn't throw money at that just yet.
Does the car generally perform sluggishly, or is this intermittent? What about the gas you put in? Has it only been on this tank? Even a severely clogged fuel filter could potentially cause this problem. I'll try to look in my service manual and re-read that part to see what other ideas GM has to offer...
John
The plugs were replaced a week or two ago. I pulled them out a couple days ago and of course they were black form running rich, but the spark zone on the plug was fine. I just bought a new heated O2 sensor and will be putting this in tuesday probably. We'll see if that works at all.
The car does perform sluggish; it also bogs sometimes when idling or at a stoplight. I go through gas like no other. I'm going through almost $10 a day, its sucking it up soo bad. This has lasted the past 3-4 weeks. I just replaced the fuel filter last week as well.
