Spark plug diagnosis - what are all those hard tiny white balls?

Q

qvalff8

Joined
Oct 29, 2007
Messages
61
Location
Idaho
This is plug 6 from a 2000 Eurovan VR6, which uses a waste spark system with 3 coils in a pack and spark plug wires.

I had rough running and a misfire code for cylinder 6. I put in an old used plug from the last time I changed them ~65k miles ago. The stock plug is NGK BKR5EKUP "laser platinum," which I think means both the center electrode and the grounds are platinum. Waste spark systems have one plug in a pair sparking center to ground, while the other sparks ground to center.
https://ngksparkplugs.com/en/resources/waste-spark-ignitions

The other plugs don't look any where near this bad (much less oily and way smaller and fewer white spheres). Cylinder 6 is the closest intake runner to the throttle valve, so maybe it gets the most oil from the PCV valve. It's been looking like this for a while, as my old saved plug 6 from 2019 is also the worst of the bunch. There's also a whole lot of electrode erosion (gap is at least 0.055" when it should be 0.028" when new (but all 6 sparkplugs are like that).

In the photos you can see the barnacles on the ceramic and the how out of round the center electrode is (sorry for the out of focus top down view). The white spheres are hard to scrape off with a small screwdriver.

I ordered 6 new OEM plugs obviously, if just to check that the new gap is much closer to 0.028" OEM spec. (Gap spec is measured with the feeler gauge inserted vertically tangential to the center electrode).

PXL_20251026_224110368.MP.webp


PXL_20251026_224105176.MP.webp


PXL_20251026_224213722_exported_1761574907816.webp
 
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Long term fuel trim is about 13%, which means lean, right? So I gotta find a vacuum leak?

How long is the term in LTFT? like, is it months of driving or hours?

Regarding ash, that's what I suspected it was. The PCV system in this van is no longer available (and was 300 bucks when it was). I installed a home made oil catch can to try to help keep oil out of the intake, but maybe I just introduced another potential source of vacuum leaks. I should take it out and check where LTFT goes.
 
qvalff8 said:
Long term fuel trim is about 13%, which means lean, right? So I gotta find a vacuum leak?

How long is the term in LTFT? like, is it months of driving or hours?

Regarding ash, that's what I suspected it was. The PCV system in this van is no longer available (and was 300 bucks when it was). I installed a home made oil catch can to try to help keep oil out of the intake, but maybe I just introduced another potential source of vacuum leaks. I should take it out and check where LTFT goes.
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Long term is a handful of seconds. You can log or whatch it change as you drive. However a really long term chart - like an hour - will continue to revert to around its mean - especially at a steady speed. Is it 13% at idle - or does it stay there when your driving down the road at 2000RPM? Vacuum leaks are highest at idle - so if it is a vacuum leak the LTFT should come down if you hold a steady RPM under load - the unmetered vacuum air will be comparatively less to the full loading.

Short term is literally milliseconds. It changes based on everything - including quality of fuel to air density.

You can also check your MAF. It should be about 1 g/s of air per liter of engine. ie 3.0l engine should be very roughly 3.0g/s at idle.
 
I have always noted deposits like this in engines that I ran a fuel additive in. Something in the fuel additive would leave deposits like this on my plugs. Maybe you are using an additive in the tank or the additives at the station are causing it. You could change fuel sources and see if they go away I suppose.
 
Thanks for those pointers SC. I believe it was between 10-14% while driving, and i didn't check it at idle.

Pontiac: The PCV system is a weird design that I don't fully understand. the valve has 3/4 inch hose on both sides plus a vacuum line that it shares with the EGR (there's a control solenoid in between). However, the vacuum diaphragm in the PCV doesn't hold vacuum, so there's a potential source of vacuum leaks.

The crankcase end of the valve attaches with a short hose to the passenger side of the engine (transverse v6) near cylinder 1. The intake side snakes around, gets heated by a long skinny metal segment of coolant piping, then gets further heated by an electrical plug. From there it enters the big plastic intake piping Upstream of the throttle valve. Then comes the throttle plate and on down to the intake runners, 6 then 5 on back to 1. The intake is more on top of the cylinder head than in front of it since the fwd van has a shortish hood compared to a Golf. And the throttle is stacked on top of the intake runners.

Most explanations of PCV show a connection downstream of the throttle, which means it sucks hard on the crankcase at idle, and much less at higher throttle positions. In my car, it hardly sucks at all at idle, which might explain the larger hose diameter 3/4 inch instead of the 1/4-1/8th I'm used to on the intake side hose.

Others in the Eurovan community have tried to get other cars' PCV valves to work with varying success. But because of the odd upstream of the throttle connection, I was hesitant. Maybe I'll get a valve from a Toyota or Honda and get rid of all the heating piping by installing it downstream of the throttle. I'm open to suggestions :)
 
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I very rarely run techron concentrate and haven't in years. I occasionally get top tier fuel but usually not (though the last two fill ups were both at Exxon). I doubt it's too much PEA, since the white spheres are there on the old plug too. (And the others #1-5 have some spheres, but fewer and smaller).
 
qvalff8 said:
Long term fuel trim is about 13%, which means lean, right? So I gotta find a vacuum leak?

How long is the term in LTFT? like, is it months of driving or hours?

Regarding ash, that's what I suspected it was. The PCV system in this van is no longer available (and was 300 bucks when it was). I installed a home made oil catch can to try to help keep oil out of the intake, but maybe I just introduced another potential source of vacuum leaks. I should take it out and check where LTFT goes.
Click to expand...
LTFT is typically built over 10 or so drive cycles and yes, a + FT indicates the ECU is adding fuel and 13% is too much. What are your Short Term Fuel Trims looking like? STFT is much more of a "what is happening right now" type of reading...but it sounds like you have a vacuum leak somewhere.
 
I have two methods of connecting to the obd: torque Pro and VCDS-Lite. Torque tells me LTFT and VCDS tells me misfires per second. I don't think I have per cylinder misfires; I need to upgrade to full VCDS for that. But there are two fields that show misfires per second. One reads ~0-2, while the other reads ~15/sec. I would guess the first is bank 1 (cyls 1, 3, and 5) and the second is bank 2 (2,4,6). This was both before putting in the new old spark plug and after, though the rough running and CEL went away with the new old plug.

Torque pro shows my usual driving STFT close to 0, but LT is still ~13%
 
I replaced the spark plugs and removed the catch can. Fully expected my LTFT to be quickly back to zero or close to it. But it didn't change after 3 start ups across 25 miles of driving. Anywhere else I should look for vacuum leaks?
 
if you think your plugs are bad take a look at the ones that came out of my fiesta, think these did 40k original motorcraft platinum plugs.
no one can tell me why they got a white coating like that. looks like they were painted lol
and the plugs never misfired too.

IMG_20150913_105331.webp
 
slybunda said:
if you think your plugs are bad take a look at the ones that came out of my fiesta, think these did 40k original motorcraft platinum plugs.
no one can tell me why they got a white coating like that. looks like they were painted lol
and the plugs never misfired too.

View attachment 313074
Click to expand...
Too hot and or too lean.

But those are the whitest I have ever seen.

What were your long term trims?
 
slybunda said:
Not sure the car is a 1995 MK3 ford fiesta and doesn't have OBD2. I think it may have obd1 but not sure how to work it.
Click to expand...
OK, so that might explain why its running so lean. I think your right in that Ford OBD1 doesn't provide live data. I had one and all I remember is it flashing a few codes.

If its that lean I would expect something like a vacuum leak. Does it have a MAP sensor - that could be faulty also.
 
Not sure on map but does have a maf sensor. Could clean it out and see how it goes. Never missfires no driveability issues either and no eml on too.
 
slybunda said:
Not sure the car is a 1995 MK3 ford fiesta and doesn't have OBD2. I think it may have obd1 but not sure how to work it.
Click to expand...
There's more to this story. That doesn't appear white from running lean to me. Those look like white deposits from burning something other than gasoline. you can clearly see how much "oil" in in the threads of the plug. How much oil does that engine burn? Are you using any additives in the oil or fuel?

Also this kind of derailed the original topic and poster... To the original poster, those deposits are certainly from burning oil. +13% fuel trims are a little far away from what I would consider normal. Do the long term fuel trims change and different loads? As mentioned a vacuum leak will be found with a considerably larger correction at low load levels when compared to high load levels.


Edit: I apologize everyone, didn't realize this was so old. Mods feel free to remove if you like
 
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