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post #1 of (permalink) Old 12-22-2001, 12:23 PM
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Carbon build up on rotor.

I had some trouble getting home this week, of course during a snow storm, and was wondering if anyone can help me figure out what went wrong so it doesn't happen again. While driving home my jeep started to run like a real piece of junk, barely had enough power to pull itself up hills, the further I went the worse it got. After basically crawling to a friends house it died, in the street, and had to push it into the driveway. It was hot, not internally, according to the gauge, but the exhaust was melting the rust proofing, and who knows what else, off the bottom of the jeep. The cab filled with the smoke. Today, three days later I went to work on it and found that the rotor seamed to have an extremely large amount of carbon black on it. Why? any ideas? Could carbon stop my ignition from firing the plugs? Why so much carbon? I did the TFI upgrade last spring. Is this my problem?

88 YJ, 4.2. TFI, 5 spd.
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post #2 of (permalink) Old 12-22-2001, 05:41 PM
 
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Re: Carbon build up on rotor.

Change cap and rotor to premium quality.
When you put the new one on. use a little dielectric grease in the groove where the cap meets the distributor adaptor.
Put a little dielectric grease on the rotor nose, and each of the inside of the cap terminals... (don't gob it on there, just a little film...)

What plug wires did you use? Cheap ones leak badly when they get wet.... (snow storm...)

Is your coil mounted where moisture can get in the primary connection (low voltage plug connector)?
You might try pulling the plug, cleaning the connection, giving it a good dose of dielectric grease, and plugging it back in...
(dielectric grease in all of the low voltage connectors of the ignition system is recommended...)

If you have the I-6 engine, that distributor is famous for leaking water in the cap...
Condensation in the cap is a real possibility too, what did the inside of the cap look like?

Carbon black? Do you mean a smooth, very black power you can wipe off with your finger? Like soot?

Or large chunks of gray/ black crust stuck firmly to the rotor nose?
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Sounds like you may have a clogged converter, or some combustion problem.

More details please...
Engine size, what plugs looked like, did the fuel milage drop off a bunch, did you check the choke...?...

So many cats, so few recipes...
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post #3 of (permalink) Old 12-22-2001, 09:04 PM
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Re: Carbon build up on rotor.

Thanks for the reply. I thought that the cap and rotor were good ones they came as a set and the cap has the brass terminals. Yes, I did put a little dielectric grease in the groove on the cap when I installed it. Maybe not enough. I didn't put any on the inside of the terminals or on the rotor tip as you suggest. I'll try it. I have a tube of the stuff. The wires may not be the best, but not cheap either, they're 8mm wires. My coil is mounted high on the block in the same location as the original one. I made a bracket up and its tight and seams dry. No cover for it though. Should there be one? The coil I used came from the local Canadian Tire Store. It looks exactly like the one used in the "Juice Box" kit. Again, I didn't use dielectric grease on the primary connections. When you talk about using dielectric grease I assume you mean on the plastic and silicone connectors not on the electrical connections. Correct? I do have the I6 engine with the new cap adapter and larger cap as specified in the TeamRush TFI upgrade. I gotta say that it worked wonders for me. My Jeep has never run as well as it does since I did the upgrade. Inside the cap was dry. The carbon was on the bottom of the cap and on the rotor, bad on the top terminal, and it was a smooth, very black powdery soot. And yes, I wiped it off with my finger (No black chunks as you ask). That's all I did and the Jeep started. I drove it all day today and you would think I dropped in a new engine. The terminals on the inside of the cap are showing signs of burn across the entire contact. Is this normal? The rotor looks fine other than the carbon I found. One other thought I had is the condenser. I didn't install it with the new coil. Should I? Thought it was to limit ignition noise. Does it have another purpose? Yes my fuel mileage dropped off, BIG TIME, I could almost see the gauge move. I haven't pulled the plugs yet, like I said it's running great today. I will check them the first chance I get. I did check the choke and it's fine. Actually was pulling off too early when the temp was below zero. Hope you didn't get bored with the long winded story. Thanks for help.

88 YJ, 4.2. TFI, 5 spd.
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post #4 of (permalink) Old 12-23-2001, 05:39 AM
 
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Re: Carbon build up on rotor.

Please try and use a little punctuation.
I'm a dyslexic, and it looks like alphabet soup when you guys make the posts one long sentence....
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*My coil is mounted high on the block in the same location as the original one.*
*I made a bracket up and its tight and seams dry.*

I-6 has coil on the side of the block, lots of splash & spray from the front wheels gets there.
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*No cover for it though.
*Should there be one?

No, don't worry about it. Use lots of dielectric grease on the high voltage coil wire to boot, boot to high voltage tower, and fill that primary connection up.
The dielectric grease isn't going to stop any connections if your connectors are any good, and anywhere the grease is, moisture and corrosion isn't.... No air, no moisture, NO CORROSION...
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*The coil I used came from the local Canadian Tire Store. It looks exactly like the one used in the "Juice Box" kit. Again, I didn't use dielectric grease on the primary connections.*

The coil is suspect unless you got it out of a box that said, "Borg Warner", "Crown" or "MSD"...
(Having said that, it probably isn't your coil.)
BTW, the 'Juice Box' is the original 'TeamRush upgrade' that someone packaged using as cheap of parts as they could lay hands on... The guy selling them used to be on this BBS...
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*When you talk about using dielectric grease I assume you mean on the plastic and silicone connectors not on the electrical connections. Correct?*

Dielectric grease is commonly referred to as 'Tune Up Grease'. I use it on every part of the ignition system.
It doesn't conduct electricity, doesn't attack plastic or rubber, and anywhere the grease is, moisture and air are not...
I pump the connectors full, and wipe off what squirts out, then use a nylon zip tie to hold the connector together.
I don't have problems like that....
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*I do have the I6 engine with the new cap adapter and larger cap as specified in the TeamRush TFI upgrade. I gotta say that it worked wonders for me. My Jeep has never run as well as it does since I did the upgrade.*

That's why I went to the trouble of putting the upgrade info together, statements just like that one...
And the fact I hated seeing guys spending $600 for a GM HEI style distributor just so the old Jeep started in the morning to haul his butt to work.... ($600 is hard to come by for working men...)

Guys can cuss my sense of humor, argue my methods, or complain about my gruff manor all they want to, but when I hear a working man say I helped, that other crap doesn't matter...
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*Inside the cap was dry.*

No condensation.... No sucked in water.... May have already burned away, or it was just vapor, and didn't condense...
Vapor will do some pretty strange stuff.... Especially when you add road salt!
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*The carbon was on the bottom of the cap and on the rotor, bad on the top terminal, and it was a smooth, very black powdery soot. And yes, I wiped it off with my finger (No black chunks as you ask).*

You have low temperature combustion going on inside the cap...
Something is catching fire. Moisture, Gasses from the engine, maybe parts of the cap terminal material if the spark is having to jump too far... Or the coil/ module is giving out
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*That's all I did and the Jeep started. I drove it all day today and you would think I dropped in a new engine.*

You just described a moisture (not wet, just damp) condition.
Buy a can of starting fluid to clean out the cap with, just make sure everything is evaporated before you put the cap back on, or KABOOM! (ask me how I know that...[img]/wwwthreads_images/icons/wink.gif[/img])

That carbon is not carbon black, it's ionized carbon, and it's conductive.
Anything conductive will sap the high voltage to ground inside the distributor, and you don't get the engine to run worth a damn.
You removed the ground (conductive carbon) for the high voltage, and the high voltage went to the plugs where it belongs...
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*The terminals on the inside of the cap are showing signs of burn across the entire contact. Is this normal? *

Better than normal, it's almost perfect. That means your rotor phasing is approximately correct.
As the advance comes and goes, the rotor nose is staying in line with the cap terminal, more or less...
(If it's all on one side, you really have to worry!)

You might want to spring for an MSD or Borg-Warner cap and rotor.
Sounds like the rotor may be too short, and I wonder what the terminals are made of if you are getting carbon in the cap...?...
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*The rotor looks fine other than the carbon I found. One other thought I had is the condenser. I didn't install it with the new coil. Should I? Thought it was to limit ignition noise. Does it have another purpose?*

The "Condenser" (actually, it's a capacitor) has a couple of functions, but ignition noise is probably the biggest.
Tune your radio to AM and listen for the ignition...
Not having the capacitor wouldn't cause this problem, I wouldn't think....... ANY THING is possible on planet earth....
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*Yes my fuel mileage dropped off, BIG TIME, I could almost see the gauge move.*

An engine on the verge of dying does some pretty strange vacuum things, one of them is draw tons of fuel...
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*I haven't pulled the plugs yet, like I said it's running great today. I will check them the first chance I get.*

If it's running pretty good, then just wait until you get a garage and some time, and just replace the plugs.
They are probably shot after the fuel soak and combustion problems...
Good time to change the cap and rotor too!
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*I did check the choke and it's fine. Actually was pulling off too early when the temp was below zero. Hope you didn't get bored with the long winded story. Thanks for help. *

Not bored... (well, maybe a little... [img]/wwwthreads_images/icons/tongue.gif[/img])
Just couldn't read this post being all one long sentence...
(I'll bet some have wondered why I break up my posts... Now you know, I'm an Idiot Savant, only without the Savant part...)
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Borg-Warner and MSD seem to make the best caps, rotors, and coils.
MSD makes the best plug wires, but they are EXPENSIVE! ($80)
They are simply the best... Best boots, best terminals, best wire, best crimping tools included!, best instructions...
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Just out of curiosity, was there slush on the road, particularly on the right side, like where the right front wheel could sling it into vapor?....

Does your cap have a vent on top?

Do you have the correct rotor? & Is it on correctly?
I-6 rotors say "6 CYL." right on the top. If your rotor doesn't say, get a new one that does.

Did you use clear silicone to seal the cap base to the distributor housing?
(you can't get the entire thing to seal with the vacuum advance being outside the cap, but plug up as much as you can with out interfering with the vacuum advance)

Is your PCV valve new? Have you checked it lately?
(if plugged, the engine may force combustion gasses up through the distributor housing)

An EGR stuck open will do strange things too...
----------------


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post #5 of (permalink) Old 12-23-2001, 03:27 PM
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Re: Carbon build up on rotor.

You posted "The cab filled with the smoke."
This sounds like a different problem, but perhaps related.
If enough craps from the road was being splashed up to contaminate the exhast manifold then perhaps it was getting into something else.
Water in the distributor cap is only one possibility but a good one. The black on the rotor may not be the problem though. The factory service manual makes a reference to this build up (see picture). You will have to make up your own mind as to if the build up on you rotor is excessive or not. Seal up the distributor as best you can, but keep looking for some other problems.


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post #6 of (permalink) Old 12-23-2001, 06:59 PM
 
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Re: Carbon build up on rotor.

I didn't rule anything out, just waiting for answers to the last round of questions...

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post #7 of (permalink) Old 12-23-2001, 10:02 PM
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Re: Carbon build up on rotor.

Just a random thought but has anyone considered carb icing? This would create a lean condition making loads of heat and the thing would run terrible, Shut it off and the ice melts.Next morning turn the key and presto it runs like a champ, been there done that.

breeze

post #8 of (permalink) Old 12-23-2001, 11:05 PM
 
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Re: Carbon build up on rotor.

My money is on the catalitic converter.Loss of power ,high temperature melting the undercoating enough to smoke.when they start to go and especially when you are running them they will turn cherry red ,

Ray
Learn to let go of what does not serve you ,but forces you to serve it
why does everyone ask if I am gonna paint it ?
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