Folks,

I recently changed the plugs on a 98 Explorer SOHC 4.0 @ about 95K miles

I noticed that the Drivers side bank is much more worn than the passenger side. The passenger side still plugs still have the shape on the tip, fairly clean...just little burned, etc.

The tips of the drivers plugs were all worn way down...almost to a nub.

I heard that the current on one bank flows in the opposite direction of the other bank (or something like that) but don't remember which bank or the details.

Has anyone else noticed this when changing plugs? and does the current flow issue (if that is correctly described) is the reason for the notable difference in the plug wear?

THANKS !

 

Kev, that is true. The sparkplug polarity is different on either bank. I forget which side is negative to positive, but I think it's the driver's side. This is true because of the "lost spark" ignition system, in which the plugs fire twice on each combustion event (every crank revolution).

That's also the reason that double platinum plugs are used in these engines. Were your plugs by any chance the regular non-platinum or single platinum type?

 

The Plugs that were replaced were all Platnum plugs. Part# Champion AGSF-22PP in both sides.

I replaced them with Autolite Double Platinums (APP103).

But those ones on the drivers side did indeed show much more wear - the posts were worn to a nub.

 

Very interesting. Since the ones that were removed were double platinum, they should have worn evenly on both banks. Maybe they just had a lot of miles on them......but then they must have been changed at least once before, since they were Champions. This makes me want to pull mine and take a look. My 00 has about 38K on it, and it probably has the original plugs in it.

When Ford installs sparkplugs at the factory, they put two different sets in; one for each bank. One bank has the platinum on the electrode, the other has the platinum on the anode. The only reason I can think of is to save a little money on platinum. I guess it adds up over several hundred thousand vehicles built.

 

AGSF22PP is a Motorcraft P/N, not a Champion P/N.
Yes, a plug in each bank fire together, in series. I have done a
schematic for the coil pack, if you are interested, e-mail me at
rlayers@us.ibm.com

This will let you see how the plugs fire together, and why
it is important to use double platinum plugs with EDIS.

 

Thanks for the info...

Does their firing proceedure explain why the Drivers Side bank got so much more wear than the passenger side...if so why/how?


Thanks much !

(and yes....the ones removed where motorcraft...I mistakenly mentioned champion b/c that was the brand of the replacements)

 

My 97 SOHC has had plug problems since day one.
I've also been through two coils.
On the first engine and the new one Ford replaced.

Only it’s the plugs on the passenger’s side.

When I went though "the show" replacing the engine with Ford, the head mechanic (who was good) mentioned in passing that he was aware of the passenger sides running hot. The side my cam spun on.
If I was in a better mood I would have pursued it.

I always notice faint brown marks on the porcelain just below the electrode only on the passenger side. Driver's side is usually clean. It could be the norm with the waste spark.
Is that part of the general compliant/question?

 

The extra wear on my 98 SOHC plugs was on the DRIVER's side.

It ran fine before - excepting from runnig a little rough from having 95K on the plugs. And runs fine now that they have been changed.

However - I was simply wondering WHY the drivers side plugs had so much more wear. Again...the passengers side looked fine (just a little burned from the use - but still had the coning shape on the tips...etc) - the DRIVERS side were burned way down - almost to a nub.

BOTH were the same double plat brand (see above posts).

Just wondering why - and if it was normal or something that needed to be addressed. But again..the truck is running fine - especially since changing the plugs,wires, all filters, etc.

 

Here I am almost 10 years later, '99 ranger with the 4.0 OHV. Same problem. Running iridium plugs and the drivers bank just seems to go through them about every year and a half to two years. When I pull them the iridium stud is straight up missing from the electrode, but again only on the drivers side. She's an old girl with 265k miles on it, and it gets whipped over a mountain every day, but no oil deposits or anything. Passenger side always looks almost new. Colors are similar. I did them today after getting a cylinder 6 misfire (rear cylinder, drivers side for those who don't know) at idle that turned on the money light pretty fast. Upgraded from Autolites to NGKs, see if they last longer.

 

OHVs have issues with heads cracking, coolant leaking into the cyls. I use Lexus Denso TT plugs. Seems to be a very good combo.

 

Just read the above. I was looking for information on the driverside spark plugs. I am reporting the same. Passenger side almost new. Driverside worn to almost nothing. The middle cylinder was the worst.
Cause for diagnosis- If I aggressively used the throttle in any gear ( manual truck) the truck would briefly hesitate. Very similar to a clutch slip. The problem was very slowly getting worse. 3 months or more and I could have continued to drive it.
I had an issue with a coil that had more than 100k on it. The current coil was approaching that so, I replaced it and kept the old one as a back up. I checked the wires and there was chafing. I don't think that was the problem after seeing the pugs on the driversside. Not enough meat to regap.
Motorcraft out, Motorcraft in.