RE: 2003 Coil on Plugs Scoop Article

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ABQTBird
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RE: 2003 Coil on Plugs Scoop Article

Post by ABQTBird »

For those of you that do not get the VTCI Scoop, there was an article in the March/April edition by Tast et. al. regarding the failure of the coil on plugs (COP) that is common to the 2002 to 2005 series of Thunderbird. I could not believe how timely it was, as I had been fighting a misfiring engine for several months, and being a stubborn do-it-yourselfer, I was determined to figure this problem out myself before taking it to a mechanic and forking out big bucks for this repair even though I know my 2003 is hideously complex. My car only has 37,000 miles, however, it is past the 10-year replacement warranty and I did not bother to check with Ford to see if they would cover the replacement.

My engine was clearly misfiring, but it would not record a code and trip the MIL (check engine light). That made tracking this problem down difficult. At first I thought is was a failing throttle position sensor (TPS) based on what I saw with my scanner, a simple but effective Autel AL519. What I saw on the TPS was a spike in % open every time a misfire occurred as pictured below. So I replaced the TPS. That did nothing. This spike was a consequence and not a cause of the misfire. As you can see, the misfire would occur every few seconds. It had gotten to the point where the car was undriveable. Another thing I observed what that the misfire only occurred at full operating temperature.

Image

Monitoring the RPMs, the misfire is easily seen.
Image

Then the Scoop arrived and low and behold, an article on how to change the COPs. I got the plug covers off without too much grief. The lower left rear screw by the brake booster was the only one that was difficult to remove. I just had to be patient with a 7mm combination wrench as no socket would fit there. Having an array of tools was handy for this job. Plenty of various sizes of both 1/4" and 3/8" extensions, a 1/4" u-joint, ratcheting thumbwheels, a 7mm socket (the article indicated 10mm, I found mine to all be 7mm, including the COPs), a spark plug socket, and some anti-sieze compound.

A u-joint allowed me to get the plug cover bolt out that is up against the power steering reservoir.
Image

I had no problem removing the driver's rear COP. This 1/4" thumbwheel helped in places where a ratchet ran into other parts.
Image

So my troubleshooting idea now was to disconnect each COP one at a time and, even though the car would run rough, I would be still be able to identify the misfiring cylinder by listening and watching my scanner to see if the misfire disappeared. I went through all eight COPs and the misfire still occurred. At that point I decided to follow the recommendation in the Scoop and just replace all eight COPs as it was possible that more than one was misfiring.

Misfire still visible as a dip with one COP disconnected.
Image

Repeating a bit of what was in the Scoop article, I did a search for DG-515 529 on Ebay and found that a set of eight ran from $50 for generic to $500 for genuine Motorcraft. So I decided to take my chances and buy the $50 set which cost the same as a single Motorcraft. Since the Motorcraft ones didn't hold up so well, I thought how could the generics be any worse? I installed the COPs with the boots that came with them as they looked the same.
Image

I thought the deposits on these looked a bit on the heavy side but not so much as to be completely fouled. Since I wasn't about to change the plugs and put the old coils back on to test again, I replaced both of them at the same time. Thus, I will never really know if it was just a plug problem. However, since I said above that it only occurred at full operating temperature, that leads me to believe it was the COPs failing at high temperature when the emissions circuits reached closed loop.
Image

I had planned to replace the plugs with Autolite single platinum AP3924, which I believe was closest to stock, but Autozone was out of them so the salesman gave me the Autolite double platinum APP3924 plugs for the same price. First I vacuumed up the New Mexico dust from the plug valley before removing the spark plugs. How so much dust got into this area is a mystery. As indicated in the article, the gaskets must not seal very well. I will inspect them the next time I change my oil and see if more dust has gotten into them or obtain replacement gaskets if I can find them for a reasonable price.
Image

I put some anti-seize compound on the plug threads and then using my 3/8" thumbwheel connected to an extension and spark plug socket, I was able to carefully guide each plug in and turn it by hand to assure it was not cross-threaded.
Image

Image

After all the COPs and plugs were replaced, I fired up the engine and went for a test drive. No more misfire and the car seemed to have a lot more power. I just have to hope the cheap COPs hold up.

Thanks to Alan Tast, Ray Clark, and Mike Goldman for the excellent and most timely article.
Last edited by ABQTBird on Mon Apr 27, 2015 11:28 pm, edited 1 time in total.
Tom in Albuquerque
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Alan H. Tast
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Re: RE: 2003 Coil on Plugs Scoop Article

Post by Alan H. Tast »

You're welcome - we've gotten several great "thank-yous" for it, but it wouldn't have happened unless Ray and others provided the info. So...we need to re-edit the article for screw head/socket size in order to correct the article for posterity and get a correction out. Tom, can you forward that to Terri ASAP so that she can get it in the next-available Scoop? (Hint - she needs material before Friday).

From the one picture of the rear where the wiring loom comes into the valley, it looks like someone tried to use some grey sealer (dum-dum?) and that the foam seal is gone. A non-hardening sealer like dum-dum might work better than the open-cell foam that was originally used (provided enough of it is in place to do its job).
Alan H. Tast, AIA
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Vintage Thunderbird Club Int'l.
Author, "Thunderbird 1955-1966" & "Thunderbird 50 Years"
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Re: RE: 2003 Coil on Plugs Scoop Article

Post by ABQTBird »

From the one picture of the rear where the wiring loom comes into the valley, it looks like someone tried to use some grey sealer (dum-dum?) and that the foam seal is gone. A non-hardening sealer like dum-dum might work better than the open-cell foam that was originally used (provided enough of it is in place to do its job).
Alan, each side had that same spot in the corner with the goop. As a matter of fact, I had forgotten which side the plug covers came off. If not for the dum-dum goop as you call it, I would not have figured out which side they went back on. I might take the passenger side off again and take a closer look as I wasn't focused on it. That side is easy enough to take off. I am the original owner, so it came from the factory that way.
Tom in Albuquerque
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Re: RE: 2003 Coil on Plugs Scoop Article

Post by vince »

Wasn't mentioned but there is a redesigned coil cover called out in TSB's. Seems while driving in rain water can get past cowl gaskets and will leak on to the covers over the coils. Apparently, the original covers were not designed to be water proof just water resistant.
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Re: RE: 2003 Coil on Plugs Scoop Article

Post by ABQTBird »

Wasn't mentioned but there is a redesigned coil cover called out in TSB's
A TSB doesn't necessarily mean Ford will cover the cost of replacement thought does it?
Tom in Albuquerque
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1962 Corinthian White Hardtop, Medium Chestnut Metallic #89 Leather, A/C, P/W
2003 Premium Torch Red/Performance White HT, Partial Accent Interior, 1 of 47.
Past T-Bird: 1960 Convertible, 1974-1978
kjschaudt
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Re: RE: 2003 Coil on Plugs Scoop Article

Post by kjschaudt »

where can I get a copy of this article? Our 2002 bird is yet again having coil issues despite never being driven in the rain nor exposed to the rain.
Best

Ken Schaudt kjschaudt "at" schaudt.us
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Re: RE: 2003 Coil on Plugs Scoop Article

Post by ABQTBird »

where can I get a copy of this article?
It is in the VTCI Scoop magazine which is only Distributed to VTCI members. There is no electronic form of it. I am not sure what issue it is in at the moment, but I can dig through them.

Do you have a particular question? I've been through the whole process and can offer you some help. The most difficult part of the job is getting the covers off of the COPs. There are just a few stubborn 7mm bolts.

As for water, yes I can sympathize with you. I am in the desert of Albuquerque and there was no evidence of water under the covers. Just poor quality electronics. I am having all kinds of electronic issues with my ABS now. It has 37,000 miles on it and I am now beginning to think these cars are not that high of quality. I will probably sell my 2003 soon and then get a 55-57 bird.
Tom in Albuquerque
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kjschaudt
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Re: RE: 2003 Coil on Plugs Scoop Article

Post by kjschaudt »

We have a 2002 T-Bird which was not covered by the extended warranty. Owned it since 2009, driven it about 6,000 miles. Only time it gets wet is when I wash it. We end up replacing coils about every year. Haven't pulled the records but I think it is often the same coils.

Am trying to determine
(0) What is the core problem and is there a fix? Hard to believe that moisture is getting under the plug cover and under the boots given that the car has only gets wet when washed. Must be the Houston humidity and a really poor original design.
(1) has Ford or an aftermarket vendor improved the design of the parts that cause this problem. I know that Ford has revised the plugs and coils for the 2002 but I don't know if this is just window dressing. Trying to figure out if the revised Ford COPs at 90 bucks each are any better than the aftermarket coils since I can buy 8 aftermarket coils for the price of 1 or 2 Ford coils.
(2) Do I replace just the bad coils or everything? If the aftermarket coils, plugs and associated parts are an improvement, I replace everything. If replacing the coils is just a bandaid, I replace just the bad parts.

For anyone interested, the never used spare blew up in the trunk this weekend. Although neither Ford, NTB nor discount tire can find a replacement, I learned yesterday that Maxxis has the tire again.
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Re: RE: 2003 Coil on Plugs Scoop Article

Post by ABQTBird »

0) The core problem is that the OEM COPs are prone to failure for unknown reasons, not necessarily from moisture, as they are hermetically sealed. They just crap out to put it crudely. Again, I live in the desert and rarely drive the car in the rain.

1) I bought cheap generic ones. I don't know if the Motorcraft design was improved or not. I thought what the heck, if the Motorcraft COPs failed, then why bother with them again (see 2). If the generics fail, I'll just buy another set and replace them all again since it is not that hard of a job.

2) Chasing down the failed plug(s) turn out to be a wild goose chase, even with a scanner in hand. I purchased one $60 Motorcraft COP and progressively put it on each plug. No matter where it was each of the eight positions, I still got a misfire. I decided just to replace them all. I checked the old ones with an ohm meter and found no difference in any one of them. I do not know what their mode of failure is. However, I did notice that the car ran fine when cool, then started to misfire when it reached operating temperature or closed loop*. While you have the covers off, you can pull the plugs and check them. See the picture above. I have 37,000 miles on the car. The plugs probably have a mileage life longer than that, but while I had the covers off, I put new ones in anyway since they are fairly cheap (see my post above for the plugs I used).

*If you are unfamiliar with the term "closed loop", it is when the car has reached operating temperature and the computer kicks in to start monitoring the O2 sensors, injectors, and everything else computer related. The car runs in open loop until this occurs. That is why it is important for computer controlled cars to reach operating temperature quickly. So when you are troubleshooting the car, it needs to be hot and in closed loop. Extreme detail can be found here: http://www.automotiveforums.com/t511544 ... _loop.html

Here is a recommendation that includes a lifetime warranty: http://www.ebay.com/itm/NEW-IGNITION-CO ... v6&vxp=mtr

Just search for DG529. DG515 may be the older part number but they all come up the same.

If you look at these things, there is no way they should cost $500 per set. They are little ignition coils just like the old fashioned ones only smaller. There are two windings in them, a primary and a secondary. 12V goes in and most likely the computer triggers them with a 5v signal. Take a look at the cut away picture in the listing above and you can see the larger 12V wires and the finer high voltage wires. There might also be some small electronics in there that trigger them from a computer signal.

You just need a good set of tools. You'll need a 7mm combination wrench and a 1/4" drive 7mm short socket. A 1/4" universal joint helps, along with and extension. You'll also need some 3/8" tools to get the spark plugs out; a standard spark plug socket and about a 6" extension. The hardest part is getting the covers off. There are just two tricky bolts on the driver's side. Also, get a small tube of sealant for the cable that comes into the back, if needed, and get a small pack of anti-seize for the spark plugs. They sell little bags of it and the checkout counter at Autozone.

That's about all I can say about it. Don't be afraid to tear into it. It is fairly simple.
Tom in Albuquerque
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Re: RE: 2003 Coil on Plugs Scoop Article

Post by kjschaudt »

This 'bird starts to run rough from the go but doesn't light the warning light. Never has. My old mechanic was pretty good and he could find the bad coil on the scope. Once it was replaced, everything ran well until the next failure. Still cost a fair penny but cheaper than the dealer. Unfortunately, he retired.

My other car is a 1953 MT-TD so I have no shortage of british, metric and SAE hand tools. I've been putting off doing this job while I shop for an analyzer that is capable of diagnosing a transient failure. Rather than putting several hundred into an analyzer, it may be best to simply replace all of the coils and plugs.

Had wondered when (if) a mint 2002 bird would start to increase in value. Given these problems, that may never happen. Perhaps I should sell this and get my wife the 50s bird that she has always wanted.
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Re: RE: 2003 Coil on Plugs Scoop Article

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Had wondered when (if) a mint 2002 bird would start to increase in value. Given these problems, that may never happen. Perhaps I should sell this and get my wife the 50s bird that she has always wanted.
I haven't checked prices lately, but I don't think these are going to increase in value. As I said in my post above, I am having a major electronic issue with the ABS. I just haven't taken it in to get fixed yet, since I don't use it as a primary car. Ford is just too expensive, but I don't know who else to trust. I have also had a power steering problem for about two years now. I don't have as much power assist throughout the whole speed range. I changed the idle speed pressure switch that boosts the engine speed when in a slow turn, but that didn't do anything. The strange thing is, it worked fine when I shut the car off, then the next morning, (summer) the problem turned on like a switch. Although the car is 12 years old now, it only has 37000 miles, which would put it only 1000 out of even the basic warranty. So I am beginning to question the quality of them. It is just a Ford after all. All my cars are Fords, and this is the least reliable one I have ever had. I don't know how many batteries I have gone through. They are undersized for the power needs of the car. If I don't start the car once a week, the battery will be dead. Must be a lot of current drain from the computers.

As for codes. The misfire never threw a code. That was what made it so confounding.
Tom in Albuquerque
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Re: RE: 2003 Coil on Plugs Scoop Article

Post by kjschaudt »

[quote]All my cars are Fords, and this is the least reliable one I have ever had./quote]
With the exception of a Dodge that we bought in 1975, every car that we bought for driving in the past 40 years has been a Ford. Had to get the first Contour that we bought declared a Lemon but every other Ford either ran for a decade or until it was killed in collisions. The 2002 T-bird was bought in 2009 with 22,000 miles on it. Within a few months, we had $5,000 of work done on the rear end. Would have known this if I had read Consumers Report. Fortunately, these initial problems were covered under the extended warranty that we purchased. Unfortunately, the coils started failing after the warranty ran out.

Again, thanks for the help. In case the problem is moisture, I'll be replacing the cover gaskets, installing a full set of aftermarket coils instead of buying an analyzer and replacing the plugs. Just located a replacement spare at Maxxis so that problem is taken care of.

Best

Ken
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Re: RE: 2003 Coil on Plugs Scoop Article

Post by ABQTBird »

I think your wife would look great in a 1956 Thunderbird. I would really like to get a 55-57 myself. Second to that, I have a fondness for the square birds, but it must be a convertible. My first car was a 1960 Thunderbird convertible, but it was NE Ohio rust bucket and I sold it before I went to college. They are hard to find now and command as much as a tri-five bird. I am going to bight the bullet and take 2003 in for repair, maybe even today. I really like the 2003, but since I also have a 1962, we are strapped for space. One or both of them will have to go before I change T-Birds.

Good luck with the repair. Hopefully once you solve that, you won't have any problems for awhile.
Tom in Albuquerque
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1962 Corinthian White Hardtop, Medium Chestnut Metallic #89 Leather, A/C, P/W
2003 Premium Torch Red/Performance White HT, Partial Accent Interior, 1 of 47.
Past T-Bird: 1960 Convertible, 1974-1978
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