dailydriver

My engine needs lifters/cam, but until I can fix that or replace the engine, I need to know WHICH valve event malfunction would cause the spark plug to carbon/load up so badly as to cause a flashing SES light mis-fire DTC??
(It is NOT oil, it is VERY hard, crunchy, carbon deposits on the electrode/ceramic/base of the plug, like an over-rich condition on this plug ONLY.)

Would the above ONLY be due to the INTAKE valve not getting opened properly because of a; collapsed/turned/broken lifter, as far as valvetrain malfunctions go??

Also, IF I am ONLY getting the DTC 305 code, and this is the ONLY cylinder and plug getting fouled out, does that mean that ONLY the cylinder 5 lifter(s) are the bad ones making all of the clacking racket????

Until I can fix this permanently (or dump the whole car), is there any plug HOTTER THAN the stock NGK TR-55s that will fit in a stock 853 head and work (for THIS cylinder ONLY)??

1 FMF

iTrader: (1)

TR5 #2683 is hotter, TR4 #3754 is even hotter.
The spark plug specs for the LS1, which is the same for the 8.1L in my truck, and the 3L GM in my boat, is
14mm thread size with 1.25mm pitch
tapered seat (as opposed to gasket seat like lawnmower engine type plug)
18mm reach (0.709")
as long as the reach is not too long then there won't be a problem,
after those whether it takes a 5/8" socket or a 13/16" is trivial,
resistor type plug is preferred but not absolutely required,
and then the heat range of plug determines the specific part number of the plug.
for the jap plugs like ngk or denso the lower number such as TR4 is hotter, TR6 is colder. it is opposite with champion plugs the lower number within the part number is a hotter plug. I don't think there is an ngk TR3, but if you find an equivalent champion plug to TR4 then find a champion part number having a higher number for heat range would be even hotter.

the pcm runs the fuel injector based on airflow, load, etc. and assumes the valve opens enough to let all of that specific a/f mixture into cylinder. if the intake valve doesn't open enough, then less of that mixture is going into cylinder and would eventually puddle up on the intake side of the intake valve which eventually becomes equivalent to over fueling

dailydriver

OK, thanks.

Yes, I found the V Power TR4 3754 at my local Carquest today.

IF the valve seal(s) is/are gone/going in that one cylinder, and oil is getting into the chamber and burning, would the resultant deposits be hard and crusty, or would their be actual liquid oil on the plug base/insulator/electrodes, even with NO visible smoke out the back of the car??

What do 'pig rich' over-fueling deposits look like, and can they be very hard, crusty, or are they ONLY/ALWAYS powdery and 'soot like'??

Also, IF a bad coil was causing a flashing SES light DTC 305 misfire, wouldn't that come back INSTANTLY after clearing the code, vs. taking until the plug gets carboned up/oil fouled to set if that were the case?

1 FMF

iTrader: (1)

a rich mixture will leave the spark plug covered in black sooty material, if you wipe your finger over it you'll get a black streak on your finger. most common are boats with carburetors that run rich and have black sooty plugs. this condition (within reason) is not a problem and the motor runs fine and makes power. richer than this will leave the plug more wet than dry/sooty especially when the spark plug is NOT firing. i have never seen hard/crusty deposits like you describe from a typical rich condition... but i have seen them on motors and outboards where seawater has entered into the combustion chamber either from bad head gasket or porous/cracked block or head. not sure if automotive coolant/antifreeze would leave deposits like you describe.
can you post a pic?
don't overlook a bad spark plug wire to be the cause... it's not hard to wreck one yanking on them to remove them.

1 FMF

iTrader: (1)

^^ this is a pic of a carbon fouled plug from running too rich.

on chart below, what does your plug look like?

dailydriver

It looks most like the "gap bridging" and "detonation" (WITHOUT the insulator/electrode damage) pics above.

I cannot post a useful pic because I cleaned it up so that I could run the car until I got either a TR4, or one of the AC Delco Rapidfire plugs (these latter are in the head now, and there have been NO flashing misfire (or even steady on) SES dash lights for almost 100 miles so far.

I also picked up a TR4 V power just in case.

The original Laser Iridium must have been destroyed by whatever is causing this condition, as it did cause a flashing misfire light on hard acceleration, even after I cleaned it up very well, and checked the gap.

Those very hard deposits were down into the inside of the threaded shell part in between it and the insulator, which I'm guessing could cause a misfire, even if the center electrode, ground, AND insulator itself are VERY clean?????

The plug wires are the fully covered Moroso Ultra 40s, less than 3 years old, and I am VERY VERY careful about pulling them off of the plugs and coils.

Besides, wouldn't the misfire light come back on INSTANTLY IF it were a bad wire, or bad coil, even with a brand new plug in there?

1 FMF

iTrader: (1)

generally if it was a bad wire or a bad plug then the misfire and poor performance would be present almost all the time very soon after... in a perfect world. but you mention "under hard acceleration" which can be a different animal to diagnose. from what you describe it sounds like a misfire where the plug loaded up and fouled but then it was able to fire eventually and heat up and clean itself off = clean electrodes. what caused that i don't know, and i don't see & experience first hand so best guess is it's electrical. you go in and work on it and accidentally prevent the problem from occurring like bad or misconnected or chaffed wire. i could see this being more probable versus valve train being the cause; valve operation does not correct itself causing what you're experiencing to come and go.

dailydriver

Yes, thanks.

I KNOW the valve train will not correct itself, and the proof is that one can still hear the lifter(s) CLACKING from 4 blocks away (you should see the looks I get around here from all of these snooty Bimmer/Audi/Merc/Lexus drivers, whose rides I can STILL kill even with the bad valvetrain!!).

It NEEDS a new engine, and I plan on getting one by the end of July (funds pending), but I need it to make it until then.

The flashing misfire SES does not totally go away, it just came on occasionally, usually under load (but not ALWAYS), but would stop for a few seconds to a minute, and then come back on again, even with the original plug cleaned off.

IF it was wires/coil/harness related, wouldn't it stay on CONSTANTLY, with NO breaks, EVER, whatsoever, or does that DTC not 'show' that way??

It has stayed away TOTALLY now for ~200 miles with the AC Delco Rapid Fire plug gapped to 0.40, but I pulled that plug two days ago and it was just starting to show some slight carboning up, just like the original, fouled out, 'crusty' NGK Laser Iridium did.

I brushed/cleaned it off and re-installed it.

1 FMF

iTrader: (1)

no it would not stay on constantly, it can come and go.
bad wires and plugs and coils can allow the engine to run fine under low load, low rpm, low heat conditions.

bad/old plugs with large gaps can result in misfires at high rpms, and under low rpm heavy load conditions.

run the engine hard and create a lot of heat... spark plugs wires can get hot and be problematic along with the engine coils.

you said in the beginning it wasn't oil, but my guess it is and the hotter plug is allowing it to burn off more resulting in a longer time before the plug loads up with deposits.

dailydriver

THANKS.

Yes, now I am thinking that it IS oil getting past the valve seal(s) in that one cylinder, maybe.
NO smoke out the back, but it does smell like it is burning oil every once and a while.