#3 Cylinder not firing

[jndnaps]

My 96 DeVille had a misfire last week. Since my gauge cluster is still out, I couldn't check for codes so I went to discount auto and they plugged in and said the #3 Cylinder was not firing. So, I though either a bad plug, wire, coil or injector. I had a new coil so I replaced that and it still had the miss. I had to go to the junk yard so I grabbed a few #3 cylinder plug wires from 3 different 96 DeVilles. I put the used plug wire on and it ran fine for about a week. Then the same problem came back. I decided to swap coils and same problem. Replaced the plug wire again and it runs fine again. What would cause the wires to go out like that. I understand that the replacement wire was from a junk caddy and could have been on it's way out. But, if this wire goes out, what will cause the wire to go bad? What do I look for next? I didn't pull the plug and didn't think that would be a problem, but who am i to think that..

Anyways, any feedback would be appreciated.

Thanks

[Cadillac Jim]

There are only a few things that will cause a consistent miss on a particular cylinder, and you have covered two of them with the coil and wire. The other most likley possibilities are the spark plug boot, the spark plug itself, and the fuel injector. I would check the connector on the fuel injector at this point. If you can use a wooden dowel from a hardware store against the fuel injector while the engine is idling and has the miss, you can put your ear against the other end and hear a tick-tick-tick if the fuel injector is working.

The platinum spark plugs used with the Northstar are supposed to go 100,000 miles but I think it best to replace them if you have any hint of plug-related issues when they have 60,000 miles or more on them. If you must change the plug, change them all. If you pull a plug, be aware that there are chemicals on the body of the plug and on the threads that are difficult to duplicate properly; I don't advise putting a used plug back in anything, particularly a Northstar or other aluminum engine.

Other things, like bad compression or cracked piston and such are very rare with Northstars.

[BodybyFisher]

Consider that this is a bad head gasket also, smell your coolant for exhaust fumes, my #2 and #3 misfired

[jndnaps]

I would think the injector would be fine since changing the plug wire fixed it for about a week. But, I'll do that if it goes out again. I thought the head gasket, but again the wire fixed the problem for about a week. I probably should have waited to see if this wire fowls out before posting, but wanted to get some ideas in case it happens again in a few days. I should probably just put some new plugs and wires on it really. I got the car with 80K and it now has 117K. I'm thinking they're original. I'll call the dealer to see if they have a record on that. Is it possible that a wire could go bad if it had a bad head gasket? Maybe doing something funky with the spark? I'm no mechanic so I have no idea.

[JimD]

....I put the used plug wire on and it ran fine for about a week. Then the same problem came back....Replaced the plug wire again and it runs fine again. What would cause the wires to go out like that.[/Quote]

Handling and flexing and pulling on the end connectors is the death stroke for carbon impregnated secondary wires.

A quick continuity check with an Ohmeter while you flex the entire length of the wire will tell the tale.

Expect to see resistance on the order of 8,000 to 10,000 Ohms per foot.

[BodybyFisher]

Good idea Jim, that would uncover if the wires were the problem or if its something else

Nothing burns out ignition wires, they might have been borderline if they are bad

[Ranger]

Pull the plug and look for carbon tracking. If it is carbon tracked, it probably took about a week to transfer that track to the "new" wire boot. IF it is tracked, you'll have to replace both the plug and wire at the same time or you'll end up like a dog chasing his tail.

[jndnaps]

Thanks again for the input. I'll see if this wire holds on first. If not, I have some good things to check out. My biggest concern was buying a set of wires and plugs and having something else be bad and burn out new wires.

[jndnaps]

Car has a miss again, but the check engine light didn't come on yet so I can't go to discount to check it. I'm gonna just get a set of plugs and wires and change them. I think the plug is bad? I was checking to see if I had a spark plug socket and extensions and all to change the plugs. I took off the #6 wire from the spark plug and saw a puddle of oil in there. I didn't see it in the #3, but maybe it's dried up? I don't think it's to good to see a puddle of oil around the spark plug though???? Think I'm in trouble.. I don't see any coolant in the oil..

When I take the coil pack off to change the #1 and #3 plug, is there anything special I need to do or have???

Thanks again for any info you cam give me.

[BodybyFisher]

The oil is OK, there are seals at each plug hole your's are leaking, not a biggie.

I don't know if OIL that has reached the plug boot can conduct current to create a misfire, anyone know?

[JimD]

Oil is generaly considered to be an insulator. Your local power company uses transformers that are oil filled for cooling.

That said, an elctrical charge can turn thousands of feet of air into a conductor; it only takes a high enough voltage.

[BodybyFisher]

Tell me about it, , as soon as you said they use oil in the transformers, I thought OH YEA

[Ranger]

When I take the coil pack off to change the #1 and #3 plug, is there anything special I need to do or have???

Just remove the ICM with the coils and wires still attached. Be advised that there is a hidden mounting bolt on the backside that you'll need to use the Braille method to remove and install.

[jndnaps]

I thought for sure I was in a lot of trouble with oil in there. As for the #3 cylinder being out again, I'm guessing the plug is bad. Maybe it has a crack in it or something. Well I'm just guessing it's the #3 again. It's missing and kinda back firing and the check engine light isn't coming on this time.

Ranger, thanks for the info on the CP. Wasn't sure if there is anything needed when the whole pack is pulled. I'm pretty good with the Braille method. That's what I had to do with my darn house computer when I had to screw in the hard drive. HP doesn't make it that easy on ya.. I'm not a big guy, but I had a hard time getting my hands in there.. I know I must sound like an idiot on here, but I have no clue.. Can you believe when I was in High School, I had 2 years of Auto Mechanics? That was back in the late 70's..

[BodybyFisher]

No one sounds like an idiot when then are working toward a solution. The question that is not asked is the stupid question not the question that is asked. Look at what I asked, can OIL complete a circuit, duhhh..... transformers are FILLED with oil.... now that is an idiotic question, BUT, although I asked it, I have now reconnected the synapsis in my brain and won't ask it again.... I asked it because you continue to get misfires, in that cylinder with oil in it.... We are all on a learning journey

[BodybyFisher]

On a totally unrelated vehicle. I am working on my mother in laws 06 Lincoln LS, she got a message on her DIC, ETC engine failsale mode. ETC being Electronic Throttle Control. The engine ran rough and lost power. It shuts down 4 cylinders and goes into limp mode similar to the NS.

I am doing research.

I found this statement, that contradicts what we said here about OIL and I think they are wrong, but I wanted to post there here for opinions, they said this

If it's an early 03 - you may have the older valve cover gaskets which leak oil into the spark plug wells, shorting out the coils. once they pop the coil cover off - they should be able to see if there is oil in there...

That statement is contrary to what we believe, the link is here

http://www.automotiv...om/t682015.html

This problem did not set a code, and believe it or not, the dealer she took it to said the coolant was a little low, and caused this code (overheating - limp mode). By the way, I checked the coolant about a month ago and it was in the range. Very odd, but we will keep an eye on it.

I do not believe the statement about the oil shorting out the coil is correct, thoughts?

[KHE]

If the oil in the plug well continues to be a problem, the O-ring seals can be replaced by removing the cam cover. Not an easy job considering it is the rear cam cover but it can be done.

[JimD]

....I do not believe the statement about the oil shorting out the coil is correct,

Correct ! !

I read that entire post and my take on the Ford failures is temperature related. Not in the transformer windings but in the printed circuit board that determines when the plug fires. But my knowledge of design and construction of Ford pieces is zero. Maybe(?) Ford has an ignition parts supplier with unresolved quality control problems.

....thoughts?

I'm searching through my CRC Handbook of Chemistry and Physics for detailed information about the properties of various insulators. But I am not expecting to find properties for various liquids.

I can offer another example where oil is used as an insulator and that is in capacitors. Oil is/was used to effectively increase the distance between the plates to allow the capacitor to operate at higher voltages without increasing the physical size of the capacitor.

[BodybyFisher]

Thanks Jim, you are my electrical sound board

We picked up the car, and they could not explain it, the best they could say was that it needed a QUART of coolant, which to me is not an explanation, we wait for this to happen again. They also said that RF from the coils could cause it

They tested the coils, and supposedly they tested good, hard to believe that bad coils could put a car in LIMP MODE...

[Cadillac Jim]

Oil pooling in the plug wells can cause a misfire by protecting a layer of moisture under it, between the oil and the head/plug. Also, additives in motor oil allow minute amounts of moisture to emulsify into the oil, resulting in a less-than-perfect insulator. Then, the oil can cause deterioration or protection of condensed moisture up into the plug boot.

I would wipe excess oil out of the plug wells with a paper towel, pushed around in the plug well with a stick.

[Ranger]

For what it's worth I once took apart an old sump pump motor and it was filled with oil. Can't be for cooling as it is submerged in water. Not sure what it was for, but I still have it in a jar. Again, not sure why. I suspect it might come in handy some day. Ah who am I kidding, not sure if it is even a good lube oil. I'm too much of a pack rat.

[jndnaps]

Well I planned on changing the plugs today, but it rained all day. I have a 67 Mustang and an 87 442 in my garage and don't want them getting wet so I'll do it one day this week. On the plus side, my gauge cluster is working again.

[CarlaValentine]

I know this is NOT necessarily a smart nor recommended idea, but, I am going to mention it anyhow as I have found that it works.

With your car running and at idle, pop the hood. Put on a heavy glove and GENTLY pull the boot on plug 3 just SLIGHTLY off the plug, and listen for the "tick tick tick" of the spark. If there is no spark at the boot, then the plug isn't the culprit and it would have to be the wire or something else before it. That would make it likely that this problem will resurface in the near future if you only change the plugs and wires without determining the definite cause.

[jndnaps]

I changed the plugs today. I looked at a spark plug chart and they all looked normal to just worn. Not bad at all, but probably the original plugs. Dealer didn't show any tune ups. Car has 119K. No oil in the plug wells at all this time. Was only in the #6 before, but I soaked that up last week and there was no sign of any more.. Maybe just from years of a very slow seep? Anyways, so far she's running great! (KNOCKS ON WOOD) So I'll see how this goes. The #3 plug did look a little worse than the others. The ceramic on the plug did look a little darker than the others, but didn't see a crack or anything out of the ordinary. Just thought I'd give you all an update.. I know I hate it when people don't update a post..

[BodybyFisher]

If those were the original plugs on a 96 with 119K, wow, they were overdue, keep us updated

Check the gaps on the old plugs, I am sure they lost their platinum pads and some have HUGE gaps