jndnaps Posted December 19, 2010 Author Report Share Posted December 19, 2010 The dealer didn't show a tune up, but maybe they did it themselves or had a another shop do it. They really didn't look all that bad really. I checked the gap on a few when I took them out and the gap was at about 50 maybe a wee bit over. I'll go out in the garage tonight and check them all. The #3 was very close to 50. Link to comment Share on other sites More sharing options...
JimD Posted December 19, 2010 Report Share Posted December 19, 2010 The gaps would be in the 0.060" range at that mileage. But believe this, the coils can produce the voltage to arc across that gap with noooo problem. My factory installed plugs were replaced at 141,000 miles and it was hitting on all 8 with no noticeable drop in fuel economy or any other symptoms before the change. And the gaps on the "old" plugs ranged from 0.056" to 0.068". I suspect the OP had either a cracked ceramic or a carbon track on the surface of the ceramic (both of which can be difficult for a novice to "see"). Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
jndnaps Posted December 19, 2010 Author Report Share Posted December 19, 2010 There was a black line on the #3 plug. I'll take a pic of it and post it later. The only plug that had that. But it didn't feel like a crack. Link to comment Share on other sites More sharing options...
JimD Posted December 19, 2010 Report Share Posted December 19, 2010 I don't need a picture to identify a carbon track Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
jndnaps Posted December 19, 2010 Author Report Share Posted December 19, 2010 I'll take one anyways so you can tell me that's what it is for sure. That's probably it though. Link to comment Share on other sites More sharing options...
BodybyFisher Posted December 19, 2010 Report Share Posted December 19, 2010 I'd like the see the black line on that plug, I have not seen a carbon track since I was a kid Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
Texas Jim Posted December 19, 2010 Report Share Posted December 19, 2010 I don't need a picture to identify a carbon track :D I heartily agree with JimD... But...it HAS been a long time since I have seen one. They used to be a lot more common...I don't know why. Link to comment Share on other sites More sharing options...
Ranger Posted December 19, 2010 Report Share Posted December 19, 2010 Sometimes it is hard to tell the difference between a carbon track and a hairline crack, ESPECIALLY in a picture. Link to comment Share on other sites More sharing options...
jndnaps Posted December 19, 2010 Author Report Share Posted December 19, 2010 I don't know anything about them so let me know. The #3 plug was the worst and the gap was just over 55 and one other plug was at a little over 55. The rest were at 50 still. Just checked them all and after re looking at them, the #3 was twice as bad as the rest.. I didn't feel a crack in it at all really. But this is the #3 plug and I'm sure that's what you call a carbon track. Link to comment Share on other sites More sharing options...
JimD Posted December 19, 2010 Report Share Posted December 19, 2010 Now that is a classic example of a carbon track. Try to take a much higher pixel count picture with sharper focus and save it somewhere you can look at it until you are old enough to use the brake pedal for a foot rest. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
JimD Posted December 19, 2010 Report Share Posted December 19, 2010 One other (serious) suggestion. IF #3 cylinder shows signs of not firing in the near future, that would be a sure indicator it is time to replace all your spark plug wires AND possibly #3 spark plug (again). Why? Because there is a possibilty the source of the original carbon tracking was a faulty #3 cylinder spark plug boot. IF that is the case, the same thing could happen again to your new #3 spark plug. Which puts the condition of the other seven spark plug wires/boots under suspicion. Once an insulator (in this case the spark plug porcelin) is carbon tracked, it is not practical applied engineering to attempt to remove the carbon. That approach does not work!! Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
jndnaps Posted December 19, 2010 Author Report Share Posted December 19, 2010 I'm gonna get a new set of wires this week and probably change them out on Wednesday. They're probably the original wires too. AC Delco wires on it now. The #3 has a Bosch now. Maybe that one's in better shape than the original wire. Thanks Jim.. Link to comment Share on other sites More sharing options...
CarlaValentine Posted December 19, 2010 Report Share Posted December 19, 2010 I know this is a novice question, but what exactly IS carbon tracking? And what causes it? Link to comment Share on other sites More sharing options...
JimD Posted December 19, 2010 Report Share Posted December 19, 2010 ....AC Delco wires on it now. The #3 has a Bosch now. Maybe that one's in better shape than the original wire. I'm confused (not to worry; that happens easily and frequently). Your #3 plug wire is Bosch as a temporary test/fix?? That would be OK as long as you install OEM ACDelco specified wires as soon as practical. If your #3 spark plug is Bosch I urge you to replace that Bosch spark plug with an ACDelco part as soon as possible. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
jndnaps Posted December 19, 2010 Author Report Share Posted December 19, 2010 ....AC Delco wires on it now. The #3 has a Bosch now. Maybe that one's in better shape than the original wire. I'm confused (not to worry; that happens easily and frequently). Your #3 plug wire is Bosch as a temporary test/fix?? That would be OK as long as you install OEM ACDelco specified wires as soon as practical. If your #3 spark plug is Bosch I urge you to replace that Bosch spark plug with an ACDelco part as soon as possible. Yes, that's one I snatched off a bone yard caddy. I'm gonna get a set of AC Delco wires. I'll call the parts guy Monday and pick them up Tuesday or Wednesday. I have 4 cars and only one on the road right now. My wife's car is having the engine rebuilt, so she's driving the caddy. So I'm without a car. Link to comment Share on other sites More sharing options...
JimD Posted December 19, 2010 Report Share Posted December 19, 2010 I know this is a novice question, but what exactly IS carbon tracking? Carbon tracking is the black trace (carbon deposit) you can see on the OP's spark plug photos. Carbon is a conductor of electricity. WHEN a layer (trace) of carbon offers a "lower" path of resistance (the proper term is impedance but that terminology difference can wait for another discussion), the high voltage pulse will follow the path of least resistance. Unfortunately, the spark plug gap is a path of "higher" resistance and the spark voltage pulse follows the carbon trace to ground. And what causes it? I'll duck this one because my applied experience is with voltages much lower than what is required to fire a spark plug at modern combustion chamber pressure levels. But I have experienced high voltage (vacuum tube application) radio frequency transmitter insulators that were carbon tracked. The only practical way to return the transmitter to service was to replace the carbon tracked insulators. Removing the carbon track is not a reliable fix. Automobile ignition high voltage wiring has used carbon impregnated wiring for decades. A source of carbon is therefore readily available. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
CarlaValentine Posted December 19, 2010 Report Share Posted December 19, 2010 Thanks Jim. That makes sense. And I already understand the difference between impedance and resistance. Resistance is found in all objects, whereas impedance depends on frequency and something else I can't remember the term for. Reactanse? Something like that... I do remember SOME things I learned in school...but only the things I found interesting enough to remember. Lol. Link to comment Share on other sites More sharing options...
jndnaps Posted December 23, 2010 Author Report Share Posted December 23, 2010 Plugs and now the wires are replaced. Car runs great! Hope that was the problem. Thanks for all the input. Greatly appreciated. Link to comment Share on other sites More sharing options...
JimD Posted December 23, 2010 Report Share Posted December 23, 2010 Plugs and now the wires are replaced. Car runs great! Hope that was the problem. Thanks for all the input. Greatly appreciated. You are welcome and thank you for the feedback which could benefit future readers. And you can bet the wires and/or the plugs was the problem. Carbon tracking is frequently an undiagnosed cause of misfire. Repair shops commonly throw parts at the problem and do not get paid to analyze why replacing the wires or plugs resolved the issue. Jim Drive your car. Use your cell phone. CHOOSE ONE ! Link to comment Share on other sites More sharing options...
jndnaps Posted January 3, 2011 Author Report Share Posted January 3, 2011 So far the car is running good with the new plugs and wires. I do feel a little something when stopped at a light. Kinda feels like the miss may be coming back. It idled very smooth right after the new plugs and wires. It's not getting any worse, but I do feel a little something. But it's still way better. Link to comment Share on other sites More sharing options...
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