Topic: Distributor cap issue

[Lu]

a month ago my jeep (95) started idling and running rough and had a noticeable loss  in power.  I popped the dist cap off and saw that the contacts were all black and gross.  I replaced the cap, rotor, and wires.  the plugs were already new.  It ran great, smooth and more powerful.  so the last few days it has been running a little rougher and not so great.  I popped the cap off again and saw the same black crap building up.  the guy at the auto parts store said just clean it.  He didn't know what it could be.  So, anyone?  what is it? 

i've also read that if the distributor shaft wobbles it could cause arching which would cause this i think.  I don't know how much it should or shouldn't wobble.  i pull the rotor off and it shakes slightly when I move it.

any help would be appreciated

[sharpxmen]

a month ago my jeep (95) started idling and running rough and had a noticeable loss  in power.  I popped the dist cap off and saw that the contacts were all black and gross.  I replaced the cap, rotor, and wires.  the plugs were already new.  It ran great, smooth and more powerful.  so the last few days it has been running a little rougher and not so great.  I popped the cap off again and saw the same black crap building up.  the guy at the auto parts store said just clean it.  He didn't know what it could be.  So, anyone?  what is it?  

i've also read that if the distributor shaft wobbles it could cause arching which would cause this i think.  I don't know how much it should or shouldn't wobble.  i pull the rotor off and it shakes slightly when I move it.

any help would be appreciated

just a guess but what coil do you have and what did you set the gap at on the plugs?

EDIT: there is always arching there, but the shaft wobbling can cause issues (like the rotor actually touching the prongs inside the cap which is not supposed to happen.

[Lu]

I have whatever the stock coil is and I am running Bosch Platinum+4 plugs which are pre-gapped and can't be gapped I don't think.   I tested the shaft more and it doesnt move back and forth but only a little up and down and slightly when turned

[sharpxmen]

I have whatever the stock coil is and I am running Bosch Platinum+4 plugs which are pre-gapped and can't be gapped I don't think.   I tested the shaft more and it doesnt move back and forth but only a little up and down and slightly when turned

dunno what to say - i would try different plugs, just buy whatever cheapest recommended plugs are (they go for about $2.50 a piece), no fancy stuff and see how that goes. Did you find these platinums in the catalog to be the ones recommended for your engine?

the movement of the shaft sounds normal to me

[Lu]

I got the plugs from napa and the guy said they were the right ones.  So you think it could be the plugs being wrong for my engine and are fouling up my cap and rotor?

[sharpxmen]

I got the plugs from napa and the guy said they were the right ones.  So you think it could be the plugs being wrong for my engine and are fouling up my cap and rotor?

i would at least double check to make sure they're the right ones.

[dwtaylorpdx]

I tried the Platinum +4's and my 2.5 did not like them. Never idled right. Ran ok at high revs though.

Went back to Copper Core std NGKs

Dave

[bumati]

I have the plus four and the e3.    Both have helped in my mileage war.     Much better than standard plugs.  I run the accel coil for big spark. 

[dwtaylorpdx]

I'm going to have to redo the coil test so I can document the
performance or lack of it from a lot of the "special" after market coils.

 

Dave

[Lu]

I'm having to clean the contacts off the rotor and cap every few days

[dwtaylorpdx]

Is the rotor getting a burnt spot or black edge as well?

Sounds like the sparc current is going too high maybe,
My YJ never has gotten great mileage out of the cap and rotor.

About 15K is the best I've done.

Dave

[Lu]

Yeah, rotor and cap contacts. I have to clean it off every few days.  What does it mean the current is going too high? 

[dwtaylorpdx]

If you gap the plug too big, (Usually above .045) and the coil cant quite handle it,
the current becomes unstable then you get secondary arcing which burns the
contacts. I've also seen mild oil leaks at the distributor shaft bearings cause blackening
when the oil deposits on the contacts and burns.

Also if the coil is old and has some internal leaking the sparc is unstable and it can burn
contacts as well.

Dave

[Lu]

When I replaced the spark plugs, I found the gap to be anywhere between .055 and .062, far above stock .035.  Could this incorrect gap have caused the cap to get black by wearing out the coil or something?  I really have no idea and I'm just throwing something out there.  So now could the coil be old and worn out and causing an unstable spark?

[sharpxmen]

if you have the correct plugs gapped properly and good cap rotor and wires should all be fine - all is left is the coil so if you suspect that to be the prob give it a shot with a different (new/old) one. Also, make sure the distributor is locked in place by the fork, but if you didn't take it out or try to turn it there's no reason for which would be clocked.