BLACK BLACK Spark plugs

Nottoofast50

Founding Member
Dec 9, 2000
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Cali
Car has been sitting for a week and a half, was running like crap and had oil coming out of the tailpipes. I pulled the back plug that has been getting fouled and it had some oil on it. Left the rest of the plugs in and pulled off the upper intake and valve covers. It sat like that for a week and a half and now i finally have time to work on it again. I pulled the rest of the plugs and this is what they all look like. Is that just carbon build up from sitting for a week and a half with the valve covers and upper off or where they fouled with oil from before? I wasn't sure if they could have carbon buildup from that or not. Is my whole motor going to have carbon buildup like that if it is from sitting thre? In other words if I can't finish taking off the heads and lower soon should i just put everything back together?
 

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So is it possible for them to be carbon fouled from sitting for a week and a half in the motor with the upper and valve covers off? I don't think it's sucking oil from the intake.... there wasn't any in the upper but i haven't gotten the lower off yet. I think it's either bad seating on the valves on the heads or bad rings. :( I also had a dist/tfi go bad on me right before this could that have anything to do with it? I was thinking maybe it wasn't firing very well and the plugs got fouled because of it. I replaced the dist/tfi and it made no difference but maybe bc the plugs where already fouled? I'm at a loss here.... I think i'm going to go ahead and pull the lower and heads, is there anyway to check if the rings are bad in the motor with the heads off?
 
actually before you pull the heads, do a compression ck, that can help you determine if your rings are bad

heres how, start your compression test, if you find one that is lower than the rest, or if they're not all within 10% or less of each other, go back to your lowest one, crank it four cycles, then squirt some wd-40, or lightweight oil into the spark plug hole, spin it for a couple seconds, then reaccomplish the test...if the pressure goes up, you have bad rings, if it stays the same, you have bad valve seats

repeat as necessary
 
and yeah, if the car was running like poo before you changed the tfi mod, then yes that would definitely cause fouled plugs...once they get fouled, they're kinda hard to burn off again. it takes a little while for the carbon to burn off, and usually leaves a gray flaky residue...same thing with oil fouling
 
Nottoofast50 said:
So is it possible for them to be carbon fouled from sitting for a week and a half in the motor with the upper and valve covers off? I don't think it's sucking oil from the intake.... there wasn't any in the upper but i haven't gotten the lower off yet. I think it's either bad seating on the valves on the heads or bad rings. :( I also had a dist/tfi go bad on me right before this could that have anything to do with it? I was thinking maybe it wasn't firing very well and the plugs got fouled because of it. I replaced the dist/tfi and it made no difference but maybe bc the plugs where already fouled? I'm at a loss here.... I think i'm going to go ahead and pull the lower and heads, is there anyway to check if the rings are bad in the motor with the heads off?

That build up is not likely to be due to sitting. Unless the car is running there isn't much carbon flowing through the chambers.
If it was caused by the bad dist, then there would have been a noticeable improvement as the better spark would have helped to clean the plugs.

Do a compression check as described above, a leak down tester can help locate the source of a leak too.
Oil can enter the chambers through rings, valves, or pcv system. Also if the lower intake gasket was positioned incorrectly you can have problems there. You will be able to tell if it is from the lower intake gasket by looking at the gasket after removing the intake.

good luck
 
txstang84 said:
and yeah, if the car was running like poo before you changed the tfi mod, then yes that would definitely cause fouled plugs...once they get fouled, they're kinda hard to burn off again. it takes a little while for the carbon to burn off, and usually leaves a gray flaky residue...same thing with oil fouling

I ran the car for 50 miles at least after the dist/tfi swap and it didn't get any better in fact it got worse. :(
 
Now that I think about it, it could be carbon that was coming out of the tailpipes, it was black and not runny like oil but just making little black patches on the ground so i thought it was oil. The car has been running SLOW for a long time now that i have been trying to track down. I have a 5 page thread on the corral about it and never figured it out. However recently it started missing. It got worse and worse and i thought it was the dist/tfi bc i had a pip sensor check engine code. I replaced both of those and it didn't get better....
 
Tfi wires where fine.... so should i put everything back together and clean the plugs and try it like that and hope they where just fouled from a bad dist/tfi or go ahead and pull the lower and heads and have them checked? I still have oil that leaks into the number 4 cylinder slowly but i'd rather not pull it all apart if i dont need to.

Taylor wires
 
mmm, how bad is that oil leak into #4? i've got a little one like that too, but it's not bad.

unless you really want to spend the money in gaskets, i'd suggest just cleaning everything up, making sure everything is connected up properly and give it another shot...
 
is there anything else that would be of huge concern, like water in the oil or vice versa?

did it start doing this after any particular event? like the head swap? or any other parts? or did it just start doing it out of the blue clear sky?
 
I'll try to sum it all up. I did the h/c/i swap thing car ran great, 13.2's @ 104 all day. 7 months down the line the car started running slow, 14's at 94 or so. I had bought a new cam as well right before it started running slow. Figured out that my fuel pump was going bad so i replaced that. Me being stupid i swapped the cam at the same time without ever running the car with the new fuel pump to see if that was the problem or not. Anyway everything gets back together and the car is still slow. I took it and had a chip burned thinking that was it but still didn't fix it. So i drove it like that for 6 months being in school and working not having time to mess with it(daily driver). During that time i've replaced/messed with every sensor or tuneup item on the car it seems like and it never got faster again it still ran mid 14's. Recently i had the problems i described changed the tfi/dist and now here we are. The leak isn't to to bad it doesn't pour out of the cylinder when i pull the plug out but there is a good amount of oil on the plug after i drive it hard although most of it is on the threads. I haven't noticed any water in the oil although i'll probably drain it out tommorow and check again just to be sure. What exactly do you mean by "cleaning" everything up?
 
just ensuring that all your connectors and mating surfaces are clean pretty much, ensuring everything is connected properly, etc.

so it started running like poo before you changed anything, then just got worse...are you sure that your dizzy isn't turning on it's own? if it just got gradually slower-now, this is a long shot-but if it just gradually got slower and not all at once, then maybe the dizzy started retarding itself a few degrees. is the timing where you set it before? what did you have it at? what's your pressure at?....

sorry to play 20 questions, but i'm still cutting my teeth on eec tuning...i'm used to carb jets and bumping the timing to where it runs best, and not worrying about a computer doing it for me.