changed spark plugs, what does this mean?

[jgilbs]

just changed my spark plugs and wires due to rough idling, VERY POOR gas mileage (6mpg - no, sadly, im not joking), and very frequent missing. The overall procedure took much less time than originally anticipated - I had figured about 2 hours, since I had heard some horror stories about that last plug, but it took about 15 mins total, including time to jack up and remove my passenger side wheel. When I removed the old Bosch plugs, I noticed that they had a significant amount of white almost powdery buildup on them, and this resulted in a gap of about .010 inches as opposed to the 0.054 that I gapped the new plugs to. What causes this buildup? Is this just normal wear? Or this is a sign of an engine malfunction? I checked my Haynes manual and I didn't see my symptoms listed in their little diagram of spark plug indicators.

Also, a few tips when changing plugs - a pair of vice grips will pull those wire boots right off, and when trying to get at the plugs on the passengers side, a 3/8" ratchet with a 2 ft piece of 1/2" EMT(conduit) works wonders in allowing you a good grip to loosen and tighten the plugs.

 

[Bill Kemp]

My Haynes manual has spark plug conditions pics on the rear cover. Sounds like ash deposits. I presume the plugs were the correct heat range so it sounds like ash. This, they say, indicates valve guide seals are allowing oil into the cyclinder which is burned and leaves deposits. Or bad gas.....

 

[410Fortune]

you run a bunch of octane boosters by chance? always run premium gas?
What plugs were they? Platinum?

All the plugs had the same white buildup?

How does it run now?

 

[jgilbs]

never ran octane boosters(well, i never did, but i got it used, so who knows), but do use seafoam every once in a while. bad gas can cause this? i goto school in iowa and they have a special ethanol blend (i think its like 25% ethanol or something, maybe higher) thats like 89.5 octane. they were bosch platinum, and all the plugs look the same. i use about 3/4 of a quart of oil in between changes(3,000k), i thought some oil usage was normal, but could this indicate bad valve guide seals?

 

[Bronco638]

Jeff,
How long have you owned the truck? How many miles does it have on the odo (and how many have you put on it)? I use 'junk' (Speedway 87 grade) gas in my '96 and don't have any issues with my plugs or mileage (15 mpg city, 20 mpg highway). Do you fill up with the ethanol blend on purpose (or have no choice)? 3/4 qt. every 3K miles sounds a little high (to me).

 

[410Fortune]

That gas is crappy, that is for sure, we get the same here in CO.
Did you re-install Bosch plat plugs again?
I wouldnt think too much of it, unless the truck is running strange.

 

[scattermaster]

just changed my spark plugs and wires due to rough idling, VERY POOR gas mileage (6mpg - no, sadly, im not joking), and very frequent missing. The overall procedure took much less time than originally anticipated - I had figured about 2 hours, since I had heard some horror stories about that last plug, but it took about 15 mins total, including time to jack up and remove my passenger side wheel. When I removed the old Bosch plugs, I noticed that they had a significant amount of white almost powdery buildup on them, and this resulted in a gap of about .010 inches as opposed to the 0.054 that I gapped the new plugs to. What causes this buildup? Is this just normal wear? Or this is a sign of an engine malfunction? I checked my Haynes manual and I didn't see my symptoms listed in their little diagram of spark plug indicators.

Also, a few tips when changing plugs - a pair of vice grips will pull those wire boots right off, and when trying to get at the plugs on the passengers side, a 3/8" ratchet with a 2 ft piece of 1/2" EMT(conduit) works wonders in allowing you a good grip to loosen and tighten the plugs.

What engine,V6? Been wondering how to get to my plugs on passenger side. Lots of stuff in the way.

 

[dreamr]

What engine,V6? Been wondering how to get to my plugs on passenger side. Lots of stuff in the way.

You just need to add a three inch body lift.
See how easy it becomes to change the plugs.

 

[jgilbs]

lol, yea a BL would help out a lot. I got new Autolite Platinums that I put in there and that seems to have really helped with the rough idle and gas mileage. The truck has 154k, Ive put prob 25-30k on it. I've got the first gen V6. I have a KKM intake kit, so maybe there was less stuff in the way, but all I really needed was a pair of vice grips for the boots (dont suggest this unless youre getting new wires as well, like i did), a spark plug socket (comes with most socket sets - its usually the bigger one, with some sort of rubber thing inside so you dont crack the porcelain of the plug), a 3" extension and a 3/8" drive ratchet. It's really not that hard, but I do recommend wearing gloves (as I do for every repair) becasue you're prob gonna be sticking your hands where you cant see very well, and who knows what sharp, rusty piece of oil covered metal will be there. All in all a pretty painless repair, something thats pretty rare for my 13 year old rustbucket.

 

[mctoy]

I've seen the whitish ash (And sometimes rusty colored) on plugs in the Phoenix Az. area, and believe it is from the ethanol's water content. In Phx. they used it in the winter months at just about all stations when I lived there...EPA

Oh and PS...I've also seen it on plugs on large commercial air conditioning equipment (454's big blocks) that ran on nat. gas which is also considered 'wet'. Nat. gas furnaces comonly get those ashy deposits on the burners as well.