Motor 4.6, year 02, super crew, mileage 187,000 +.
Codes, CEL,..... none.
A look at mode 6, test 53 at all cylinder missfire counts showed cylinder 1= hex 51, cylinder 2= hex 51, cylinder 5= hex 3f00 and too high.
These numbers in Dec = 81, 81, and 16,128.
Long term fuel trims are not close to being equal as an indication something is out of normal tolerence but not out of limits.
But still no codes set.
The system has wide latitude.
Serviced cylinder 5 only.
Found water trapped in the plug well for some time with indication on the boot and plug shell well coated with slime.
Cleaned and inspected the boot, the coil, tested for spring length, greased up the tip, and replaced plug.
Test drive with several short drive cycles then retested mode 6, test 53.
Results on cylinder 5 is hex 3f or dec count 63.
Low counts like this is of no real problem unless they begin to rise or are intermittantly high.
It remains to be seen what effect this has on the long term fuel trims that are somewhat different bank to bank as there could be other added causes to look at on a high mileage motor..
Bottom line is no codes, no CEL does not means everything is perfect in motor land, just within a point no codes are set for anything out of limits far enough.
The conversion from Hex code to Dec is done from your computer calculator program. The data in Hex or Dec you see with any peticular Scanner depends on how the designer did the design for display.
This shows the value of a Scanner and being able to interpet the data and see things before they become a more serious problem..
Good luck.

 

Nice catch Bluegrass
I need to buy a better scanner,I have freeze frame data which does help, but as you just proved, sometimes even live data is not enough.

I looked for the craftsman scanner you mentioned in another thread but I don't think it's available up here.

Leaning towards an autoenginuity pc based

 

Keep in mind Vaper... there are other software packages out there that can do the same or near the same thing for less money.

scantool.net, myscantool.com and obdsoftware.net are a few that I have read into, but have not bought yet.

And there is the Android option: OBD DROIDSCAN PRO and TouchScan (OBD Diagnostics)

Thanks Bluegrass for the information. I too need to invest in a better scanner and will make sure that data logging is one of the features.

 

I neglected to mention that what caused me to look was a poping noise in the radios.
This arc noise is outside the cylinder at some point, to be picked up by a radio.
Good luck.

 

Thanks for the info TrdLtly,I'll do some reading on those

 

That is awesome to think that something so minimal as a little popping on the radio would lead to something else that could have been eventually harmful to the engine and not to mention your mpg I would suppose.

 

Additional information;
A cylinder can present a very noticable missfire at idle and accelerstion without setting a code or CEL lamp.
The reason is if it's an intermittant action, the PCM can cancel the count as far as setting a code or light but does add it to the missfire count as seen in mode 6 test 53 observations.
Usually it is a boot that is leaking, moisture in the plug well or even a faulty coil.
Once moisture gets in the well it has a hard time being driven out because there is vertually no airflow to allow that to happen in a short period of time.
As the engine cools the moisture comes back to the water phase.
As the motor heats the water goes to the steam phase, is suspended in the space and can condense on the coolest part, so the cycle repeats over and over as conductive causing the missfires.
Even if the boot looks good it can still be leaking at the plug connection point.
For an intermittant missfire, the cost of a new boot is worth the change to see if the condition clears up before replacing the coil.
Any other cylinders with missfire counts that show up on a repeat observation but don't seem to be a problem might be cleared by replacing the boot for the same reasons.
This is what you call fine tuning the igntion to near zero missfires.
Missfire only during a specific condition of OD and light throttle is usually a coil with shorted turns that has low output so a boot may not or may not add to it.
Good luck.

 

At what point (miss fire count)will the pcm unlock the torque to rule out road shock? Does it do this immediately if locked up or wait for a certain number of miss fires?

 

I have no specific information as to your question.
Normally the TPS postion and road speed determine when the TC 'locks' and 'unlocks'. OD is much the same but is a seperate function and considered a gear change.
For effects of drive train variations, there are two filter calculations used in the missfire algorithm.
One is called the 'deviant acceleration values' and evaluated for noise.
The other is 'symmetrical acceleration deviations' values and evaluated for noise.
In drive train deviations the noise or signal changes are more symmetrical as opposed to deviant type cylinder missfires.
The differences between these two is how the program handles the effects of crank rotation timing.
The program considers a noise free deviant acceleration exceeding a max limit, a missfire. What it does with TC lockup is not mentioned.
You can read about this on page 9 of the 02 model year overview, under Generic Missfire Algorithm Processing.
Good luck.

 

Thanks Bluegrass,While trying to nail down a miss fire once I noticed the unlocking of the torque,for no known reason.I have read the pcm will unlock the torque to rule out the drive shaft being the cause,via rough road ect,maybe this only applies to a random miss fire?
I will check out your recommended read
Thanks again
Do you have a link for this?

 

http://www.motorcraftservice.com/vdi...f/obdsm208.pdf

 

Here is another article about Ford Misfires using Mode $06 from Motor Magazine: MOTOR Magazine Article | MOTOR Information Systems

 

There ya go. It's the basis of what my replies have been about.
On a board like this most owners only arrive here when they have an issue.
Without background and tools to work with, it's difficult for them to understand explaination or advice beyond change this or do that.
Most want to be told a positive fix and not be bothered with the learning curve.
Bottom line is if an owner is going to do his own work, then he has to get involved in understanding and using common sense, or it just becomes an exersize in waisting money on parts in hopes of a quick result.
Bewhere of the ads for the MD doctor type readers. It's not what they would like you to think. It does no more than any other low end reader.
It's sometimes sad to see a dealer or a shop that won't go to any depth in diagnostics and sends a vehichle out not knowing if the trouble has really been found.
It's sometimes the shop is told how the tech will work that causes it and /or the mechanics are not fully trained indoing so.
Good luck.