Lets play a game: Name all the possible causes of a "cylinder misfire"

J

jimmyducati

New member
I have had this problem since I bought the car 2 years ago and have yet to find a remedy for it. Under hard acceleration I immediately get a CEL with strong bucking of the engine and the A/C stops blowing cold. The CEL stays on for 1-2 minutes and when I try to press on the gas the bucking comes back while the light is on. Using the torque app, the CEL is cylinder #6, everytime.

So far I have replaced all of the spark plugs with Iridium NGK plugs all gapped to .030, and I have swapped every coil to another cylinder hoping the misfire would follow a faulty coil. I have also ensured that all of the cheap ass rubber on the tip of the coil and around the neck of the coil is in new condition and have replaced a few that had imperfections. I have also checked and double wrapped the knock sensor wire that runs along the front of the engine that is known to wear and short out.

The only item on each cylinder I have not touched are the injectors. I had an appointment at the local dealer this morning and after driving the car aggressivly we were able to get the CEL in short time, the tech said it was again cylinder 6 misfire, but he claimed the code flagged the coil.. I protested stating that I have swapped all of the coils around and the CEL is always on #6, he maintained that the injector cannot cause a misfire...

SOO.... Name all the possible causes of a cylinder misfire on an ecoboost engine!
 
A) Try running a few tankfuls of Techron or BG44K through to clean out the injectors as much as possible.  Gunk/grime in the fuel rails can accumulate at the ends of the rails.
B) If misfire continues, swap injectors to see if the misfire follows, if so, replace injector
C) Look closely at the PCM to see if the PCM is at fault

Have the COPs been verified visually AND electrically?  Cracking, melting, carbon tracking, excessive resistance, etc.  Worth keeping an extra, new COP on hand for R&R testing.

Fuel injectors do fail on the EB engines, and even on the NA version of the 3.5 engine (have seen a few cases on the Edge, for example).
 
Always being the same cylinder I think OP is on the right track suspecting injector since misfire didn't move after coil swap and spark plug replacement also had no effect.

Other general things for misfires:
Bad fuel pump (HPFP on the engine or low pressure feeder pump in the fuel tank)
Carbon build up in cylinder
Intake valve deposits
 
All great ideas, but at this point I am not considering the COP to be a factor... I have already tried 3 other COP's and the misfire is still on #6. I am beginning to suspect a possible short in the COP harness for the #6 cylinder, but if it were a short it would be all the time, not just in a WOT run. I am also hesitant to suspect carbon, as the problem has been around since I bought the car at about 20k miles. I always run 93, and buy only from name brand stations (mobile, shell) so quality of gas isn't at the top of my list, and Ive done multiple cans of 44K, great stuff, but not the solution. The fuel rail pressure raises as high as 650 psi, is this normal or low?

I am more than competent with a wrench and would rather buy specialty tools to do a job myself than pay ford do do it, but is an injector swap something that can be done in a garage at home? I don't want to try and fix the problem only to make it worse... Suggestions on where to get maintenance manuals or literature that can help in the job (if its a DIY kinda thing)?
 
650 psi is not very high. At wot I see close to 2200 psi.

It does sound like an injector problem. They are a known problem.
 
jimmyducati said:
All great ideas, but at this point I am not considering the COP to be a factor... I have already tried 3 other COP's and the misfire is still on #6. I am beginning to suspect a possible short in the COP harness for the #6 cylinder, but if it were a short it would be all the time, not just in a WOT run. I am also hesitant to suspect carbon, as the problem has been around since I bought the car at about 20k miles. I always run 93, and buy only from name brand stations (mobile, shell) so quality of gas isn't at the top of my list, and Ive done multiple cans of 44K, great stuff, but not the solution. The fuel rail pressure raises as high as 650 psi, is this normal or low?

I am more than competent with a wrench and would rather buy specialty tools to do a job myself than pay ford do do it, but is an injector swap something that can be done in a garage at home? I don't want to try and fix the problem only to make it worse... Suggestions on where to get maintenance manuals or literature that can help in the job (if its a DIY kinda thing)?
Click to expand...
Oh hell, that is way low!

On the 2013 and 15, the pump maxes at 2150 but I've seen 2750 on the rail sensor.

What are you logging with?

If that's the max rail pressure you are seeing, I would not drive the car till you get this handled.



 
Any datalogs to share, Jimmy?  I think that would help us tremendously in helping you. 

Manuals can be had off EBay, or you can subscribe online at places like Chilton's/AllDataDIY/Mitchells etc.  Check to see if your local library gives you free access to Chilton's.  The one free library link I had doesn't work anymore :(

As far as carbon tracking, I was not referring to engine internals, I was referring to the the contact area between the spark plug and COP boot:
http://www.ngk.com.au/spark-plugs/technical-information/spark-plug-analysis
http://www.tomorrowstechnician.com/under-the-hood-cop-patrol-tracking-down-coil-on-plug-misfires/

An example of diagnosing & fixing:
http://easyautodiagnostics.com/chrysler/2.0L-2.4L/carbon-tracks-misfire-1

EDIT:  When pulling the #6 COP, be sure to check for signs of oil leak as well, though I am assuming that since you haven't mentioned issues, that it should be OK.
 
FoMoCoSHO said:
jimmyducati said:
All great ideas, but at this point I am not considering the COP to be a factor... I have already tried 3 other COP's and the misfire is still on #6. I am beginning to suspect a possible short in the COP harness for the #6 cylinder, but if it were a short it would be all the time, not just in a WOT run. I am also hesitant to suspect carbon, as the problem has been around since I bought the car at about 20k miles. I always run 93, and buy only from name brand stations (mobile, shell) so quality of gas isn't at the top of my list, and Ive done multiple cans of 44K, great stuff, but not the solution. The fuel rail pressure raises as high as 650 psi, is this normal or low?

I am more than competent with a wrench and would rather buy specialty tools to do a job myself than pay ford do do it, but is an injector swap something that can be done in a garage at home? I don't want to try and fix the problem only to make it worse... Suggestions on where to get maintenance manuals or literature that can help in the job (if its a DIY kinda thing)?
Click to expand...
Oh hell, that is way low!

On the 2013 and 15, the pump maxes at 2150 but I've seen 2750 on the rail sensor.

What are you logging with?

If that's the max rail pressure you are seeing, I would not drive the car till you get this handled.
Click to expand...
X2 on the FRP^^^ ...should be close to the numbers FoMoCo posted
 
Ill double check on the fuel pressure, I checked that when I first got the car and realized the problem... So I may have pulled a Hillary Clinton and "mis-remembered" the number. All of the spark plug wells are totally dry of any oil.
 
Ok, fuel psi at WOT peaked at 2160 psi. I'd love to datalogg for you guys.. No clue how. I use the torque app, how does data logging work there?
 
Gotta be injectors bc I just had all 6 of mine replaced. I was having the same exact issue except I had stuck open causing mine to have lumpy idle, stalling issues, etc.
 
jimmyducati said:
Ok, fuel psi at WOT peaked at 2160 psi. I'd love to datalogg for you guys.. No clue how. I use the torque app, how does data logging work there?
Click to expand...
Haha, awesome, that first number had me sweating and it's not even my car, lol....

There should be another pid in torque for rail pressure, see if you can find it and report back that number.

If the car is having trouble building pressure in the rail that may also indicate a leaking injector.
 
Here is my first try at data logging, although Im not sure how much good it is going to do.. The PID's that I thought had the most promise of showing exactly where the problem starts are not supported (cylinder misfire, Injector pulse width, etc). I started data logging, then immediately did a WOT pull for each run. The last run was when the misfire happened again and I continued data logging after it began misfiring, although I did stop accelerating when the misfire occurred. To my untrained eye, aside from some fluctuation in the a/f ratio, noting seems obviously wrong.

The data logging was done after loading the LMS 4+ 93 octane tune. I just filled the tank with 93 octane this afternoon.

Any other PIDs I should datalog to get a better idea of what the injectors are doing?

 
Great start, Jimmy!  Would like to see, in addition, Fuel Trims (short term fuel trim 1&2, long term fuel trim 1&2), oxygen sensor data (O2 sensor bank1 sensor1, O2 sensor bank1 sensor 2, O2 sensor bank2 sensor1 and O2 sensor bank2 sensor2), and transmission gear.  Also add in custom pids such as the Knock Retard PID (first one in the list, available here).  Don't use any of the builtin Torque PIDs that are not returning data.

We also need a lot more continuous data from each "run", so you might wind up having 10's of thousands of lines of data that we can graph & analyze.

Right off the bat, A/F ratios measured & commanded are not nearly in sync, so you do appear to have an issue.  Measured drops to 0 in some cases, which indicates O2 sensor issue also as a possibility.  A/F ratios (measured/commanded) themselves WILL vary, depending on the situation (what gear, what throttle position, load on engine, etc) so I wouldn't focus on that (for now).  Fuel rail pressure looks OK though.
 
Here is the latest log I recorded this morning on my way into work. I let it record for a couple minutes, during this time I accelerated aggressively and as usual it misfired. I included all of the PID's in torque that looked like they could help with the problem, but the misfire pid wasn't active unfortunately. Does anyone have a misfire pid that has been written for the ecoboost?

 
I'm pretty sure there are "misfire event" & "misfire trips" gauges figured out...maybe on the 1st page of the thread "torque pids take 2"

Rich

 
There is a misfire widget built into torque.

Scroll down 👇 when selecting gauges and you should see it.

Iirc mode 06 data shows them as well.
 
STFTs look out of whack, Jimmy, possibly trying to compensate for inadequate fuel flow.

No O2 data?  That is surprising!  I assume the car was warmed up before the WOT runs?

Misfire counts are listed as "Cylinder X Misfire Count" and "Total Number of Misfires" in the Add Sensor list.  You can also monitor Current Drive Cycle Status as a display in Torque.  This, along with Emissions Monitors is listed directly under the Select Type of Display list.

Much easier to see Mode 06 data in OBDLink software, unfortunately only works with OBDLink hardware tho.
 
Ill look for those PID's this afternoon, Ill include them in the next log, but I'm not sure its going to be necessary. I just pulled a couple of new codes when I got back to the office, Bank 2 sensor 1 O2 sensor is out of limits and the Bank 2 Catalytic converter is also reading as bad.. That explains why the O2 data was missing in parts of the graph and could explain why the fuel was out of whack at times. Both a symptom of excess fuel being shoved through the exhaust, so it kinda confirms fuel injector suspicions. Im probably going to pay the 25$ to get the year subscription to chiltons online (unless someone has a SHO maintenance manual on digits) so I can pull the injector and have it either tested or replaced...

I guess now Im in the market for a set of catless DP's... great way to get a performance part is to justify it to the woman that the part needs to be replaced anyway!!
 
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