Oil fouled, or carbon or what?

[Junkie2100]

so, my engine hasnt been acting right for a little while now, trying to figure out whats going on and my spark plugs definitely look like theyre fouling just cant tell if its oil fouled or what its not ashy but its definitely a dry crust with a bit of a shine to it, dont know if anybody here can identify anything but figured id ask

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[Schurkey]

What vehicle? What engine? How old are the plugs?

 

[90 Silverado]

Exhaust valve seals are usually the cause on the 305 and 350 V8's , I find that using Autolite platinum plugs in these engines don't foul as much as others.

Mine ( seals )have never been changed, I just get the smoke on startup. Not enough to worry about.

Doug in P.R.

 

[Junkie2100]

What vehicle? What engine? How old are the plugs?

the vehicle itself although not very relevant is a 1994 chevy 1500, the engine is a 1992 tbi 454 from a suburban, the plugs i cant remember how old they are i havent driven the truck regularly in years, they are at least a few years old, but might have less than 50 miles on them.

i can break down the series of events but if someone can visually read spark plugs without reading this part and making assumptions that would be helpful thats more what i was looking for was an unbiased read to see which path to follow

Spoiler: what had happened was

i went out one night about 5 years ago when it was around -10F probably a little colder, truck wasnt having it. got a few blocks died, got it started giving it some gas, hauled ass home without letting off, wasnt sure about it and didnt need to go anywhere i worked from home so i left it for a while

come back a few months later, start driving it again, seems okay enough, but i start seeing dark crap at the bottom of my coolant reservoir, appears to be oil, but no trace of coolant in the oil i can find and the cylinder pressure appears to be ok last i checked so i dont think its a head gasket, could be the cooler in the radiator cracked, could be the intake gasket, either way it was just a tiny bit wasnt even really losing oil, pressure seemed normal, wasnt getting hot at all, and i didnt have the money or time to deal with it, and i really didnt ever take it anywhere, so i drove on it for the time being

a while after that, it started to die randomly, it would die out after having run for a while, then refuse to start, it would eventually start back up and run fine but it was definitely having issues, so i parked it again, sat for a couple years basically

come back, do some things to it, still runs like garbage, replace the temp sensor and the distributor which yes i set properly, it didnt seem to like 4btdc so i went 0btdc, now when i try to start it, gas shoots up out of the throttle body, and my plugs apparently look like this after the entire ordeal though i dont know at which point during all that i changed them if at all, im pretty sure ive changed them somewhere in there, but i cant say for certain, and i dont feel particularly comfortable even trying to start it with vaporized gas flying out of the top, but not having a working vehicle is horrible, and im out of work now so i cant just load the parts cannon i cant afford to replace anything unless im absolutely sure it needs replacing

 

[Junkie2100]

Exhaust valve seals are usually the cause on the 305 and 350 V8's , I find that using Autolite platinum plugs in these engines don't foul as much as others.

Mine ( seals )have never been changed, I just get the smoke on startup. Not enough to worry about.

Doug in P.R.

could be, might not be related to my main issue but im just trying to figure out if it is. because my problem is something to worry about lol

 

[Junkie2100]

oh yea and one other thing its started doing is stuttering and acting like it wants to die even cold now, and the RPMs have trouble dropping below 800, it starts to drop, act like it wants to start to stall, and ramps back up

 

[Schurkey]

Is your question that crappy plugs can make the engine run bad for years; or
an engine running bad for years can make the plugs look crappy?

Either way...the answer is "yes".

Get new plugs. Verify the cap, rotor, plug wires. Test for ignition coil spark output using a spark tester calibrated for HEI ignition. Probably install a fresh O2 sensor.

Drain the old gas out of the tank--pull the fuel filter, run the fuel pump until the tank is empty. Refill with fresh gas and a new filter. Test fuel pressure. Change oil. Make sure no oil is coming up through a failed PCV system.

Then connect a scan tool, look at all the sensor data; and all the output data. See what--if anything--looks goofy.

 

[Hipster]

i can break down the series of events but if someone can visually read spark plugs without reading this part and making assumptions that would be helpful thats more what i was looking for was an unbiased read to see which path to follow

What's to read? They look to have cooked on oil, and the porcelain is dark. The tan color is darker then what you would see just from fuel additives. They look neglected. The second one appears to have some fuzzy loose crap on it. Hopefully that came from the exterior rather than from inside the chamber. I see 2 plugs. One of other 6 might reveal something different.

You mentioned gaskets and an oil cooler in the radiator as reasons to mix water and oil but those are not the only reasons. -10f and the coolant turning to slush can break a block or head. I say this because -10f seems to be where your problems started. Was the antifreeze ever tested?

Schurkey provided a very complete list but I would add a proper compression test and a cooling system pressure test which I think both tools can be borrowed from the parts store for no cost before any real money is spent.

 

[gearheadE30]

Those spark plugs just look old and nasty to me, and like the engine is getting a bit too much fuel and probably burning some oil or really bad gas (carbon deposits). But could also be if it's just idling, only running in warmup, something like that, and never actually getting driven and getting hot enough to clean all that crap up.

Get new spark plugs and rule them out. They're cheap.

 

[Junkie2100]

Is your question that crappy plugs can make the engine run bad for years; or
an engine running bad for years can make the plugs look crappy?

Either way...the answer is "yes".

Get new plugs. Verify the cap, rotor, plug wires. Test for ignition coil spark output using a spark tester calibrated for HEI ignition. Probably install a fresh O2 sensor.

Drain the old gas out of the tank--pull the fuel filter, run the fuel pump until the tank is empty. Refill with fresh gas and a new filter. Test fuel pressure. Change oil. Make sure no oil is coming up through a failed PCV system.

Then connect a scan tool, look at all the sensor data; and all the output data. See what--if anything--looks goofy.

neither, my question is whats the most likely cause for the plugs looking like that. oil in the cylinders, too much fuel, or is it just normal carbon buildup. the initial issue wasnt plugs, im trying to track down something else, and knowing if theres oil getting in the cylinders or that its getting too much fuel or whatever would help diagnosing the overall issue. the plugs were not like this when it started guaranteed theyve been changed since it started acting up