Results 1 to 8 of 8

Thread: Ford Coil Pack issues

  1. #1
    Join Date
    May 2007
    Location
    Kansas City, Missouri
    Posts
    13,433

    Ford Coil Pack issues

    So I had planned to move my daughter tonight, but a week or so back my old Ford started acting up, which I drive about 3 times a month. A few years back I bought a scanner that I can hook up to my laptop and log most of the sensor activity on the engine, transmission, and ABS system. However, like most computer related stuff, things improve over time. So my old ford (1999 model) was having a misfire on a cylinder. The computer on the 99 won't log which one is having misfires until they reach a certain threshold, usually around 3%, however the computer will react and shut down fuel supply when it reaches a smaller threshold, in my case it was around 1.3%.

    So when the vehicle computer senses that there is sufficient misfire to warrant reaction, which I mentioned, it checks around every 5 seconds, it will shut off fuel supply to said cylinder for 30 seconds to keep damage from happening to the catalytic system. Well, though the computer is trying to help, it won't throw the code to show which cylinder is having the issue until it reaches that previously mentioned 3% threshold.

    So I had spent about $100 for the Ford ODB license to be able to diagnose just this sort of issue, but turns out that the scantool software can only do what the vehicle manufacturer logs. What I ended up spending 2 hours trying to diagnose I was actually able to do with the free software that comes with the scantool that I bought. That software (ODBWiz) allowed some low level monitoring of the sensors, refereed to as "Mode 6" or "$06" The trick is that it doesn't log, but you can refresh and capture a snapshot of what is happening with the engine. So as I mentioned, I had to try to capture the issue while the misfires were happening, which weren't shown while the cylinder was disabled for 30 seconds by the truck's computer, so I had a 5 second window to capture which cylinder was misfiring when the trucks computer did allow the cylinder to fire. Once I understood this concept, I got the information captured.

    Now why does the misfire happen? Three things, lack of fuel (bad injector or issue with injector), bad spark plug, or bad coil. In my case, the spark plugs are getting old. It's the second set as I've got about 200k on the truck, so I need to do a plug change. However, as the plugs get worn, the voltage required to jump the gap on the plug increases. The coil pack adjusts for this, but if there is a defect in the coil pack, such as a pin hole or crack, the spark will jump through the defect and ground to the engine block causing the misfire as it won't make it to the gap in the spark plug.

    While this is not related to woodworking, I hope that my experience helps someone else. And if I have to relate it to woodworking, I stepped through my dry rotted wood trailer deck tonight while moving my daughter and this will relate to an upcoming thread on me putting a new deck on the trailer.
    Darren

    To a small child, the perfect granddad is unafraid of big dogs and fierce storms but absolutely terrified of the word “boo.” – Robert Brault

  2. #2
    Join Date
    Mar 2015
    Location
    Parker County, Texas
    Posts
    1,488
    I don't even try to figger out these new computerized cars. My girlfriend had a 2005 Crown Victoria that was the Interceptor Model. It actually belonged to the Texas Rangers. No, not the baseball team. Ran like a screaming banshee. But, it started having some electrical problems, including the coil packs. I told her to not to spend money on it and just take it down and trade it in. Now she drives a Fusion and loves it. Actually, I kinda like riding around in it too. Though I admit I did like the CV and all the sprawling room it had. Oh, well.

  3. #3
    Join Date
    Jul 2009
    Location
    Amherst, New Hampshire
    Posts
    10,600
    The misfire in my wifes car was due to a vacuum leak. After replacing coils, plugs and a few other things I found a plastic check valve on a vac line in the back end of the motor that had a crack in it.
    Faith, Hope & Charity

  4. #4
    Join Date
    May 2007
    Location
    Kansas City, Missouri
    Posts
    13,433
    Quote Originally Posted by Bob Gibson View Post
    The misfire in my wifes car was due to a vacuum leak. After replacing coils, plugs and a few other things I found a plastic check valve on a vac line in the back end of the motor that had a crack in it.
    I checked that one, had an issue with it before, very similar, except it would hardly run at all with that issue.

    I'm limping it along another year hopefully, the list of things needing done is quickly outgrowing the desire to dump money into it.
    Darren

    To a small child, the perfect granddad is unafraid of big dogs and fierce storms but absolutely terrified of the word “boo.” – Robert Brault

  5. #5
    Join Date
    Jun 2008
    Location
    GTA Ontario Canada
    Posts
    12,246
    Well i totally and infinitely admire your tenacity, skill and patience at debugging. My Rock Auto shotgun approach would have been to hit the whole lot and be done something like Bob did.

    Got a similar problem in the Honda Civic. What we did was kill off the plug wires and distributor and new plugs, wow what a difference they made for very little money given Rock Auto pricing. At same time for the misfire on the 3rd cyclinder ,randomly, (It pops a code now and then) i purchased a single fuel injector to replace that cylinders fuel injector. After that i dunno there aint much more.

    I am convinced after the work we have done on the Civic to keep it on the road that its worth it economically to do this with cars but only if the basic body shell has stood up well to the Snow/salt winter climate. The civic is amazing in this case.

    The key i find is regular oil changes and really good oil.

    On my Jeep now 10 years old that Hemi is amazing. All it asks for is a good oil change every 5000km. I get Castrol High Mileage oil and use a good quality Bosch filter and honestly i swear you can feel the difference after oil change. Seriously helps if you can work on your own car. The tools i have purchased for this purpose from our HF equivalent, have paid for themselves so many times over its incredible. But the big bonus to me is knowing any work was done with diligence. I really wish i could find a trustworthy mechanical crowd.
    cheers

  6. #6
    Join Date
    Dec 2007
    Location
    Tellico Plains, Tennessee
    Posts
    4,351
    Not having any troubles with misfires on my F150 (2003 model), but last Saturday was getting noise from the front drivers side wheel ... when I braked, could feel a shudder, so figured I had some problems with the brake caliper or something.... nursed it home from Knoxville and called AAA on Monday.... when the tow truck arrived, I noticed something laying on the ground under the tire... turned out to be a brake pad had fallen off the wheel...... a mere $586 repair for new disc, new calipers, new brake line and labor....
    Chuck
    Tellico Plains, TN
    https://www.etsy.com/shop/TellicoTurnings
    My parents taught me to respect my elders, but it's getting harder and harder to find any.
    If you go looking for trouble, it will usually find you.

  7. #7
    Join Date
    May 2007
    Location
    Kansas City, Missouri
    Posts
    13,433
    Yeah, brakes are on my list too, hopefully not $600 worth.

    Sent from my SM-T710 using Tapatalk
    Darren

    To a small child, the perfect granddad is unafraid of big dogs and fierce storms but absolutely terrified of the word “boo.” – Robert Brault

  8. #8
    Join Date
    Mar 2007
    Location
    Southeast Pa
    Posts
    2,019
    Darren usually mode 6 logs from one crank until the next one. Mine is a 2004.. 5.4 but that is the way it works... Mode 6 is a really nice diagnostic aid that only Ford used to have..not sure if that is still true. I don't find these new cars much harder to work on than the old ones, except for things like the 2 piece Ford plugs where half stays in the hole!. At 100 plus an hour for any grunt work on a car I figure I can take 5 times as long and still make great money for a retired dude. And knowing most of the mechanics understand less about the new stuff than some of us old tech types makes it an even easier call. About 90 percent follow Robs style and all the parts they changed along the way were bad..at least that is what they claim.. Plus they don't charge Rock auto prices for all the parts they change..

Similar Threads

  1. Model T Ford
    By Dan Mooney in forum Off Topic Discussion
    Replies: 7
    Last Post: 05-17-2010, 12:31 AM
  2. ford fix needed!!!!
    By larry merlau in forum Off Topic Discussion
    Replies: 20
    Last Post: 11-20-2009, 11:25 PM
  3. Ford Fusion
    By Kirk Constable in forum Off Topic Discussion
    Replies: 14
    Last Post: 01-20-2008, 07:38 PM
  4. Small knife, made from coil spring
    By Alan DuBoff in forum Handtool Project Showcase
    Replies: 3
    Last Post: 07-09-2007, 07:06 PM
  5. Ray Ford
    By Rennie Heuer in forum Welcome and Introductions
    Replies: 4
    Last Post: 01-17-2007, 03:46 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •