gettin' there

[troonbop]

I recently changed my spark plugs and wires, thanks to all the good advice on this forum moving the engine wasn't as much trouble as i though it would be. It runs stronger, but still a little rough - i think i have one cylinder still missing, the one closest the driver. Anyway, my question - is it possible for only one half of the coil pack to go so it only affects one cylinder? I searched the forum, can't find the answer. Thanks to everybody in the past who helped.

[jeffcoslacker]

Originally Posted by troonbop

I recently changed my spark plugs and wires, thanks to all the good advice on this forum moving the engine wasn't as much trouble as i though it would be. It runs stronger, but still a little rough - i think i have one cylinder still missing, the one closest the driver. Anyway, my question - is it possible for only one half of the coil pack to go so it only affects one cylinder? I searched the forum, can't find the answer. Thanks to everybody in the past who helped.

Not that I've ever seen. I don't think that can happen. MAYBE if the tower was cracked, and it was throwing spark somewhere else, but not likely.

Is it missing at idle, or all the time?

If just at idle, you're sucking air near that cylinder.

[troonbop]

Hi Jeff, thanks for the quick response. In the meantime I was looking up about catalytic converters and their effect on performance, maybe it's the cat. The engine runs rough at idle and pretty much all RPM ranges and is louder than usual. Thing is, the cat's only about three months old, low mileage on it since then.

[richtazz]

If there is a visible crack in the coil tower to that cylinder, I would say yes. Normally a coil problem will effect both cylinders fired by that coil, but it is not impossible for the coil to have an internal problem and work fine on one cylinder but not work on the other. If you have access to an inductive pick-up timing light, hook it to each plug wire and point it to a dark area where you can see the spark pattern. IF you see one that skips, there is your problem cylinder. If all the spark patterns seem constant, then you may have a bad fuel injector on the cylinder in question causing your miss.

[decollect]

Originally Posted by richtazz

If there is a visible crack in the coil tower to that cylinder, I would say yes. Normally a coil problem will effect both cylinders fired by that coil, but it is not impossible for the coil to have an internal problem and work fine on one cylinder but not work on the other. If you have access to an inductive pick-up timing light, hook it to each plug wire and point it to a dark area where you can see the spark pattern. IF you see one that skips, there is your problem cylinder. If all the spark patterns seem constant, then you may have a bad fuel injector on the cylinder in question causing your miss.

Rich, thanks for the idea!! I've got a '97 with an intermittent miss, mostly at idle. I've been "sitting on the fence" trying to decide with to replace, injectors or coil packs first. I have an old inductive light that because of newer cars, hasn't seen use in years. THANKS!!!!

[troonbop]

I notice the problem gets worse when the car is thoroughly warmed up after ten or so miles. Any ideas what that means?
Thanks.

[decollect]

Originally Posted by troonbop

I notice the problem gets worse when the car is thoroughly warmed up after ten or so miles. Any ideas what that means?
Thanks.

Tron, I'd have to then agree with Jeffco and Rich. It's starting to sound like you have a cracked tower. I know on the older, distributor type ignitions, that I've seen that problem before. When the cap or tower on the cap would crack, it wouldn't be much of a problem when it was cold. However when the cracked component warms, the crack gets larger, changes the distance between contact points and produces erratic spark. It would stand to reason that you MAY have a similar problem with your coil pack. I'll re-read the posts, but if you haven't checked/changed them, plug wires would be suspect as well. When they're cold, they're alot less flexible then when they are warm. If you have a crack in the insulation, it may be widening as they warm. It really doesn't take much to mess with your spark from what I see/hear.

I can't see temperature messing with your fuel delivery to produce the problems you're describing. Yes, I know that temperature in SOME cases will mess with fuel delivery, but my experience suggests that is limited to vapor lock or other fuel evaporative problems. I don't think that is what you're dealing with. Blocked fuel lines or filters don't really care what temperature they are. However please note I AM more familiar with the older engines. Look to Jeffco, Rich, or Cadgear and a few others for more recent, up to date info.