All, I have been battling a horrible missfire problem for months, the truck has been into the dealer several times without ever finding a solution. Through a member on this board we were able to solve the problem, DawG (board member who helped me) actually was the one to find the issue I just took a few ford mechanics to the bar to get some answers out of them ;-). The probelm was a random missfire that seemed to change a little with the weather and at different engine tempuratures. The way we found the problem was to have one person in the truck with it running and put it in reverse with a little load on the engine, then ( this must be done either at night or a VERY VERY dark garage) we lightly misted all the plug wires with water. After a few min (eyes needed to adjust) we could see small blue tracers running up and down the NEW wires. The problem is that there is something in the Ford coils that will cause the missfire problem. It appears as though Dawg's theory is absolutely correct in that some vehicles have developed a malfunction that causes the coil to more than double the voltage of the spark, this voltage will actually "cook" the wires from the inside out. On my vehicle they were able to measure as high as 90,000 volts. I did get an Ford Certified mechanic to disclose to me that he has seen this issue before and the only remedy was to replace BOTH the wires and the Coils at the same time. He also verified that once this happens your wires will only hold up for a very short period of time.
Apparently once the wires are bad IF you replace the coils only they also will only last a short period of time, due to still having bad wires. Therefore replacing both components at the same time should cure this issue. He did not seem to think that the computer was the cause of this just a problem with the coils which will perpetuate itself if you only replace one item at a time. I have 500 miles so far with no codes, no
missfires, no issues whatsoever she is running like a dream. I ended up going with the OEM coils by Wells and the Ford Motorsport 9mm wires.

I hope this helps.

Michael

 

That makes a lot of sense. The entire point of the coil is to convert a low volage, high amp source into a low amp, high voltage source, thus generating a spark. There are plans out there to turn ignition coils into something that can shoot a spark 6+ inches through the air. A Tesla coil is the ultimate version of this. Look them up, they're cool!

So, what might be happening is some type of failure or short in the coil is changing it's properties enough to make it generate a much higher voltage than it should, which allows it to jump across the insulation. I'm very surprised they don't have a test for the coil that could detect it. Heck, you might even feel a tingle if you grabbed the wire with that kind of juice in it.

 

Trust me .... IT TINGLES
and the only codes it ever threw were random missfires.

 

Ok, maybe "tingle" is an understatement. I've had my whole arm go numb from a model A spark coil I was playing around with, putting 12 volts into it and getting a 3 inch spark.

 

Anyone who was ever unfotunate enough to be holding the plug wire on their minibike while an A-hole friend pulled on the recoil starter knows that numbing jolt all too well.

In my younger days couple of us put together a V8 powered Vega that always ran like crap when the weather got wet. One particularly damp evening it ran bad enough to warrant a look under the hood where we were treated to an electrical fireworks show that would have made Edison himself proud.

 

Hey F0RDMAN how is that supercharger working out now??? I know u have over 177K on there... I'm planning on doing the SC on my 4.6L Expy so as far as reliablilty is concerned I was going to try to do everything i can. Can you come up with more things to watch out for?

what kind of plugs are you using?
I should do the ftvb thing? (what is that and were can I get it?)
with the jacobs what exactly did you purchase?
I'm very familiar with fixing up Sport Compacts but I have no clue where to start with a Ford?
Thanks

 

I have had no problems whatsoever witht he Kenne Bell, I am currently using the Denso IT-20 plugs, they are spendy but they seem to burn much more of the fuel and I notice the power difference. The FTVB is a transmission mod that can be purchased through Mike Troyer at Superchips, I highly recommend going through him he is one of the most knowledgable people I have spoken with. If you are going to larger tires I would definatly suggest swapping the rear axle to the lightning 9.75, it will hold much more power and the posi in it is much better than the one in the 8.8. I have blown up 2 8.8 rear ends. Also you will need to shorten the driveshaft almost 2 inches to go to the new rearend. If you have anything else let me know.

 

wow that was a great reply thx!!! about the L rear end, where would I attempt to get that?

Also about your Jacobs ignition, what was included with that, this ignition I'm very unfamiliar with?

 

Getting back to the premise of the original post, I must point out what appears to be an inconsistency in the hypothesis presented for the random misfires.

The coil will only generate voltage until the spark plug fires. When the plug fires, the energy stored in the coil is discharged through the plug and the cycle can be repeated for the next firing sequence.

If the coils are generating excessive voltage, that means that the plugs are not firing at the proper voltage. The only reason for this is too much resistance in the firing path. The only explanations for THAT is a plug with too high of resistance, wires with too high of resistance, or a faulty ground connection from the plug' body to the engine head/block.

It would be interesting to note what spark plug (make and type) is installed in your engine, the spark plug gap, and the age of the plugs.

The new style "fine-wire" plugs are supposed to promote lower firing voltages. Again, I am curious to see which plugs have been in use.

Steve

 

Ok, I have heard this same argumernt from 3 ford dealers before I found a mechanic who would actually admit that this problem was accurate. I have tried the factory plugs, Bosch plugs, Champion plugs, I have had Magnecore Wires Autolite wires and Ford Racing wires(2 sets) , I also tried 2 sets of coils one stock one from accell... the only solution was to change them both at the same time and we did indeed measure a voltage of over 90,000 volts at the plug with a scope. I understand this sounds odd but trust me over $1000.00 worth of parts and labor says that this IS the solution. Oh ya BTW I have gotten most all of my money back from Ford for parts that were not nessesary as well as some of the labor charges. I am currently running the Double Platinum Autolite plugs and the Ford Racing wires.

 

I purchased a 2003 lightning rear axle from a wrecking yard for 700.00 with the stock 3.73 gears. I then installed a new set of Yukon 4.10's in it. The only mods needed to install the axle are New Emergency brake cables for the lightning disc brakes ( if you currently have drums) and shorten the driveshaft aprox 2 inches due to the "nose"of the 9.75 axle being longer than the 8.8. Other than those 2 items the axle is no problem and just bolts directly in. I have had the jacobs since the truck was new and I belive there are actually better ignition systems out there now, although I have always been very pleased with the one I bought. The ignition improved the fuel economy as well as providing a very noticeable seat of the pants difference. Let me knwo if you have any other questions...