Coil going bad... how to tell which one?

We had a customer tow his car into the shop for no-start issues. Was running fine and then wouldn't start one day. I did the usual check for spark and fuel....got them both. Pulled a plug to check spark at the end of the wires and noticed the electrode completely even with the metal part of the spark plug. Like it was gone....

Pulled the rest and found them in the same shape, lol. I was in awe. This was an 89 Ford F-150 with 195K miles.....ORIGINAL spark plugs. The owner verified it too, he was the original owner and said he's never had them replaced. Let me tell you....I've never seen anything like it.

Needless to say, I sold him the works....cap/rotor/wires/plugs/fuel/air/pcv...AND a coil! :D
 
They weren't only worn down. They were also like little pointed cones. Definatly not a recommended situation. Did not think to check the gap at the time.
 
It is possible they were the originals. Mark said he took it to a shop a year or so ago to have them replaced because he did not want to do it in his parking lot. I would not think a non-dealer would instal Ford platinums without charging an xtra fee since the plugs are like 5-6$ each. I would not be suprised if a dishonest mechanic simply cleaned them (if at all) and then charged for new ones.
 
What's the mileage? Our plugs are supposed to be good for 100,000. I intend to replace mine a little earlier than that, but that's damn nice.

White isn't a nice thing. Could be burnt oil, could be burnt coolant. Was it a "clean" white with little or no residue or chunky and wet?

By the way, if you think THAT'S bad, you should've seen one of my El Caminos... I did the plugs on my gold '87 and two of them crumbled in my hands. CRUMBLED! I didn't even exert force on them! On top of that, all of them had NO electrodes at all. It was shocking to know that the car was running fine. But hey, that's a Chevy for ya!

I'd love to see a Honda do that.
 
For what it's worth, here's a pic of the worst one.

plug2.jpg


Most of the rest run from tan to a medium to light gray.

No, it wasn't wet. I've seen plugs that were fouled with coolant from a bad head gasket (Ford 3.8 V6 anyone?) and this doesn't look like them. Most of what I'm reading says it's running way lean or hot. I will say it's been acting pretty anemic for a while, even with the new plugs.

Thoughts?
 
That's the "clean white" I was referring to.

It's probably a mixture of things, but most of all, just wear. You're probably burning just a tiny bit of oil, which is totally normal for these cars with higher mileage on them. Losing a quart of oil between oil changes isn't bad. Even two isn't THAT bad.

It's possible it could be running lean, but I doubt it. Seeing as how you said your other plugs range in color, the only thing that I could think of off the top of my head is a slightly clogged fuel injector, if it were to be running lean at all. Do you have a scan tool handy? Running a quick sweep over the sensor readings (particularly the MAF) may be of help. If not, no biggie.

Have you ever flushed out the fuel rail and injectors on your car? We have a machine called MotoVac at our school... Works wonders. Basically, it hooks directly into the fuel rail of a vehicle and loops the lines going from the pump back into the return, so that your vehicle runs entirely on this machine instead. You run the machine for about 15 minutes without the car running so it can flush out the rail, then run the car for about an hour. Cleans out your fuel rail, fuel injectors, valves, combustion chamber, catalytic converters, even the mufflers. We've had cars come in that would stall out 3 times before even getting into the fuels lab... And wheel out running as good as it did when it left the showroom floor.

If you ask me, you could use a Motovac treatment. The plugs don't look absolutely horrible, it just sounds like you got some mileage on there and she could use a good ol'-fashioned enema... What's odometer at anyway?
 
M Darrah said:
For what it's worth, here's a pic of the worst one.

plug2.jpg
Click to expand...

Which plug was that and what is the gap?

Give me a pic of all 8 in the order they lay in the engine...

4-8
3-7
2-6
1-5

I'm guessing that plug came from 7 or 8.
 
The car's only got 71K on it, but probably 55K - 60K of that is stop and go city driving. My commute each day is about 15 miles one way, so it doesn't get a lot of "burn out the cobwebs" time. And ask Trixie, I'm not much of a hot rod driver.

JP, I saved the plugs in order as I was taking them out, but since they were all so similar in condition, I didn't bother to mark them afterwards. I believe this one came out of the forward driver's side (4?). The forward one on the pass. side had a lot more oil in the tube sitting on top of the plug than the others, which I understand is somewhat normal. Otherwise the plug itself was about the same as the others. I'll take a look at the gaps when I get home.
 
M Darrah said:
JP, I saved the plugs in order as I was taking them out, but since they were all so similar in condition, I didn't bother to mark them afterwards. I believe this one came out of the forward driver's side (4?). The forward one on the pass. side had a lot more oil in the tube sitting on top of the plug than the others, which I understand is somewhat normal. Otherwise the plug itself was about the same as the others. I'll take a look at the gaps when I get home.
Click to expand...

I should've been more specific...

4-8
3-7
2-6
1-5
Front

The forward drivers side is #5.

I always mark the plugs I pull and examine them as they were removed from the engine. This can indicate overall condition as well as individual cylinder problems. It is odd for one plug to be significantly different from the others. There may be subtle differences that could be considered normal.

The plug pictured appears to be running 'hot'. This could be from excessive gap, a lean condition, detonation or a combination of all.

Be2lose said:
Why is that?
Click to expand...

I've been told if you put an O2 bung in the headers for tuning, put it in the drivers side. The reasoning is it has been shown on these motors if there is a lean condition due to fuel starving it will show on the rear drivers side cylinders first if there is no specific malfunction between the individual cylinders. The fuel rails are fed from the passenger side and the rear drivers side is furthest from the fuel source.

I don't mean to sound alarmist - it's most likely nothing to loose sleep over. If it were to have been mine, I would've considered replacing them with a set of one step colder plugs, such as 22C's, based on the appearance. If one should ever pull the plugs and find them dark and sooty - you should run one step hotter plugs.

Such a recommendation should always be made with consideration of the particular driving habits the user.
 
AssFoe said:
MotoVac at our school... Works wonders.
Click to expand...

+1 for the MotoVac! My friends have one and it definitally works! Just make sure you actually getting the correct treatment....I mean....take it to a reputable mechanic. The 1 liter bottles cost 80 bucks so they may skimp on your treatment!

M Darrah said:
For what it's worth, here's a pic of the worst one.
Click to expand...

Ok....when you said the electrode was worn down, I was expecting WAY worse. I modified your picture to show what the plugs I mentioned above looked like....

NO JOKE!

plug2.jpg
 
budpytko said:
If you have a code reader, pull the codes...it should tell you which cylinder is missing....

1-2-3-4 on passenger side ---- 5-6-7-8 on drivers side. BTW...if no code readre, Auto Zone does it at NC!
Click to expand...

Yep. I have had two go out and the code reader wasn't worth diddly. Heck it took Ford two days to figure out it was a coil.
 
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