Feels like a misfire?

Phillip Diagnostician Alaska Posted   Latest   Edited  
Resolved
Driveability
2014 Ford Explorer XLT 3.5L (8) 6-spd (6F35) — 1FM5K8D81EGA75850
Stumble
No Codes

Vehicle is a NON ecoboost AWD

Customer complaint is hesitation while accelerating. Vehicle was taken to another shop and had spark plugs, C.O.P boots(maybe), air filter replaced & fuel injection service done. Customer also believes problem may of gotten works but is unsure.

I’m able the verify customer complaint. The vehicle has a stumble like a misfire(I think anyways) when driving. The problem happens only around 20-24 MPH and around 40 MPH give or take a few MPH. Problem also seems to be more noticeable when vehicle is fully warm. When driving the vehicle you have to give it light throttle for the problem to occur. If you give it WOT the stumble will not happen or if you do like a passing a car event, the problem will not occur. It happens on a flat road and up a hill. Never happens if you are coasting. Around turns or going straight.

Checked systems for codes and had none in PCM, but had a C1137:64-60-Reverse Gear Switch & U0401:68-AB-Data Received From ECM A Is Invalid for the ABS module. B1218:00-0A-Transmitter ID Code & B10D7:8F-08-PATS Transponder for BCM II. U0422:00-2F-Recived Invalid Data From BCM for IPC. B137F:17-0A-Steering Wheel Left Switch Pack for steering column control module. These codes don’t seem to be related to the current situation. Recorded engine data and analyzed after a test drive. Did not find anything out of the ordinary. Test drove vehicle several times to confirm that vehicle has indeed a misfire or so I believe. Also misfires seem to be random and not related to 1 cylinder. Performed visual inspection of engine and found Throttle body is dirty and intake boot clamps were not tight. Tightened clamps and retest drive and no change. Removed front row spark plugs and did find plugs gaps are at the end limit of the gap. Plugs are Motorcraft and platinum. Retest drove vehicle several more times and recorded engine data. Nothing seems out of place. Checked for TSB’s and none relate to this concern. Tested ignition coils current ramp with a pico and all coils seem to be good(sorry did not save the wave form, but wish I did now). Performed KOEO fuel pressure test and have 58 PSI.(specs call for 58 PSI KOEO/KOER) Performed fuel injector test and readings were all over the place. Allowed engine to fully cool over night and retested injectors. Injector tested more stable next morning. Results are as followed. Injector 1. 23 PSI drop, 2. 22 PSI drop, 3. 24 PSI drop, 4. 24 PSI drop, 5. 25 PSI drop & 6. 26 PSI drop. Performed test twice and got damn near same results. At that time I had sold the customer injectors and also re gaped the plugs. Got everything back together and did my basic engine data analysis since I had the intake off and all was good. Test drove vehicle again and problem is still there. I went next door to our transmission shop and they test drove it. They didn’t believe it was a transmission shop. So now I scoped the primary side of the ignition coils. The all looked the same so I only saved the one cylinder but in the picture I had something that looked funky to me. Honestly I’m no expert on ignition coil analysis. I also disconnected the AWD system and tried to manually shift the transmission at different RPM’s and that did not make a difference.

I am hoping someone can take a look at the scope capture and tell me if what I am seeing is fine or if there is a problem. Also hoping that someone could help give me some direction here. NOTE: The first pic is of the car idling. The second one is when to problem occurred at 20-25 and 40 MPH for your reference and the last two pictures are just to show you what I'm looking at. I also included the pico captures for anyone that wants to review them. They are all of cylinder #2 even they are numbered 1-3. I just wanted multiple recordings. 

UPDATE: Using the snap on verus pro. I Checked mode 6 misfire data before test drive, during test drive twice & after test drive. While never shutting the vehicle off. All 6 cylinders read zero counts of misfires. I recorded air/fuel sensors, & short/long term fuel trims. Fuel trims never went past +/- 5% during stumble event. Air/fuel sensors were reading around +/- 200 mA. (I don’t really know how to use wide band oxygen sensor on a test drive effectively yet for misfires, so I don't know if they will be useful to someone else). I then recorded transmission data. During the event I noticed that the TCC slippage actual RPM would go from like 420 RPM’s to 5 RPM’S and continue to fluctuate from -7 to 120 ish RPM’s during the stumble event. TCC slippage desired RPM would drop to 20 RPM’s at about around 14-16 MPH accelerating and stay their till I reached cruising speed or even a deceleration cruising event. When the vehicle was cruising, desired and actual were at 0 RPM’s. I can assume from my knowledge of transmission that this is TCC locking as it should. When I gave the vehicle gas the TCC slippage actual RPM would go to 200-250 RPM’s and be pretty steady. This would be were the TCC is releasing and free spinning I could assume. Now at this point I’m thinking maybe the transmission shop might have been wrong or maybe this pid’s just are not accurate. So after grabbing a monster energy drink and watching funny videos on Youtube, it downed on me that if this vehicle is stumbling then engine RPM’s would probably be affected also. So I re recorded the transmission data, but this time I added the engine RPM’s and vehicle shift points.(so I could tell when the vehicle was shifting) Test drove for about 5-10 minutes trying to get the vehicle to stumble as much as possible. It’s snowing here in AK so traffic is nightmarish for test drives. I reviewed the engine data again and found that every time the vehicle stumbled the RPM’S seemed to dip also slightly. At first I wasn’t sure if it was just nervous foot, but then I remembered that I was accelerating during this time. I then added the TCC clutch slippage actual RPM’s again. I noticed that very time the TCC slippage actual RPM’s dipped in a none transmission shift condition and during the engine stumbled event, the engine RPM’s always seemed to dip with it. To me that seems like I’m in the right diagnostic funnel but I wanted someone else opinion. Cause maybe it is just me wanting this to be the problem and I want to be $5000.00 sure that this is the cause.

NOTE: I still need to get the cylinder balance test data again, re record primary ignition current and voltage. Then maybe try to disable the EGR but I figured this was a good sopping point for me today. 

Last update: So what I did was get to the transmission connector and de-pin the TCC. I then wired up a test light to the TCC pin. For safety reasons I put a fuse inline so in case if something worked loose or anything went wrong that the fuse would blow at the battery. I then test drove the vehicle and to my surprise the shudder was gone. I then drive the vehicle several more times while recording engine load, calculated load, throttle position & AWD command %. I then reinstalled the TCC wire and test drove the vehicle and the shudder came back. I also recorded the same engine data as mentioned above. I then compared those 2 data sets and found that they were damn near close to each other. The reason for this was I wanted to make sure that same test conditions were the same other then the TCC. This made me confident to call the transmission. Unfortunately we don’t do transmission work at this shop except for the basics and the customer decided to not go ahead with the work so I can not confirm this was the actual problem other then I was confident. DO take this with a slight grain of salt as I can not confirm the repair if you come across this exact same problem. Do take note that their was no TSB’s or to my knowledge any pdates for this problem. I do believe that the TCC would have a slight lock up that was enough to cause turbulence inside the combustion chambers

0
Helpful
Interesting
Geoff Diagnostician
Hawaii
Geoff Default
 

I would check the misfire logs in Mode$06 data. Check before driving then several times during a fault-inducing test drive, (idling off the road of course....but don't cycle the ignition). This will tell you whether it's a random cylinder or just one. Then I would load test that coil with an adjustable gap tester. If you don't have history of servicing. then all old spark plugs get…

+2
Default Ð Awarded
Phillip Diagnostician
Alaska
Phillip Default
 

Plugs are only a week old. I did check mode 6 and all read zero but I will do it your way to just be sure.

+1
Default Ð Awarded
Thomas Technician
Virginia
Thomas Default
 

I wish I was sharp at analyzing ignition wave forms. From the little I learned from watching ignition analysis class it seems like there is a problem with the secondary ignition internal to the combustion chamber. I agree that the burn line does not look good at all towards the end. Have you watched the upstream o2s when the misfire stumbling occurs? it may not show anything significant if the…

0
Default Ð Awarded
Stuart Mobile Technician
Illinois
Stuart Default
 

I agree with Geoff Welsh in checking mode$06​.​Also check your fuel trims when occurs to see if it is a misfire if they are lean or rich misfires​.​Good luck

0
Default Ð Awarded
Phillip Diagnostician
Alaska
Phillip Default
 

Plugs are only a week old. I did check mode 6 and all read zero but I will do it Geoff Welsh's way to just be sure. I can't for the life of me remember the fuel trim numbers, so I'll go back and check those too.

0
Default Ð Awarded
Randy Diagnostician
California
Randy Default
 

sure sounds like egr problem . Disconnect egr and test drive. that would explain the turbulence in capture

+1
Default Ð Awarded
Phillip Diagnostician
Alaska
Phillip Default
 

Will give that a try. Never had one cause a problem of idle but first time for everything.

0
Default Ð Awarded
George Owner/Technician
Alabama
George Default
 

Is this hash on all secondary waveforms ? If just on 1 I would suspect worn cam lobes

0
Default Ð Awarded
Phillip Diagnostician
Alaska
Phillip Default
 

They all seem to be the same.

0
Default Ð Awarded
Roy Technician
California
Roy Default
 

Hello , Are the PCM calibrations up to date ? -Instagram- rmdiagnostic831

0
Default Ð Awarded
Phillip Diagnostician
Alaska
Phillip Default
 

I have not, but I do not know how that will honestly make a difference. Since their is no TSB's that I could find that relate to this concern.

0
Default Ð Awarded
Roy Technician
California
Roy Default
   

Just wondering but I have witnessed software updates fix some crazy situations . what about the torque converter? possibly torque converter slip making it feel like a miss ? take a sample of the Trans fluid and look for signs of clutch material . you can also monitor the tcc rpm pid in graph and look for signs of drop when the miss feeling occurs . -Instagram- rmdiagnostic831

+1
Default Ð Awarded
Ray Diagnostician
Ontario
Ray Default
 

You're not sure which cylinder is misfiring and if you have a 4 channel scope, you can scope 4 COPs at one time. Set the scope to 500 ms/div and when you do a brake torque, try to find the rpm where the engine misfires. Slowly bring the rpms to 1,200 or 1,600 to force the misfire. Once you can "feel" the misfire, turn the engine off and scroll thru your captures till you find one of the spark…

+2
Default Ð Awarded
Helpful
Phillip Diagnostician
Alaska
Phillip Default
 

I only have one 10:1 attenuator. The vehicle never has a problem power braking through any of the RPM ranges. You have to drive it like I described above to make it stumble. But You are right I should be doing 1 bank at a time and comparing them. Just cant with this time.

0
Default Ð Awarded
Troy Owner/Technician
Washington
Troy Default
 

Sure sounds to me like a possible torque converter lock up time, and since it will not happen under hard accell I would check to see if it happens at that time

+1
Default Ð Awarded
Roy Technician
California
Roy Default
   

You beat me to the punch ! Well done . -Insatgram- @rmdiagnostic831

0
Default Ð Awarded
Phillip Diagnostician
Alaska
Phillip Default
 

They didnt see anything wrong with the TCC pid's but I will look at it again. Because well you not, never know if they missed it.

0
Default Ð Awarded
Roy Technician
California
Roy Default
 

I just diagnosed a Ford Escape that had the similar condition . it felt like a miss no codes . Monitored tcc rpm and every Time the miss feeling would occur I saw this on the tcc rpm pid . The tcc locking up . Bringing rpm almost to 0 . Funny thing is that escape has the same 2.3l if I’m not mistaken . Hmmmmmmm? -Instagram-@Rmdiagnostic831

0
Default Ð Awarded
Phillip Diagnostician
Alaska
Phillip Default
 

My vehicle is a 3.5L V6 non ecoboost, so I don't know. But I will be rechecking the TCC

0
Default Ð Awarded
Roy Technician
California
Roy Default
 

Oh yeah sorry lol

0
Default Ð Awarded
Ray Diagnostician
Ontario
Ray Default
 

You could try to shift the transmission into Drive 2, then drive it, that way the TCC won't engage.

+2
Default Ð Awarded
Agree
John Diagnostician
Texas
John Default
 

I don’t see a problem with the waveform. Doesn’t look like a secondary ignition issue at all. You can also scope primary and if there is a secondary problem it would bleed back into the primary Ignition. I would use a vacuum gauge to get direction. i Would lean toward restricted exhaust or Torque converter.

0
Default Ð Awarded
Phillip Diagnostician
Alaska
Phillip Default
 

This was on primary. Bank 1 is under intake so I had to get access to PCM and get on the primary side control of the circuit. I ended up doing them all at the PCM since I was there. A TCC sounds possible but a restricted exhaust would give you no power at all or higher load demands, not at a medium load demand and be fine at lower and higher I would think? Plus the MAF hits like 180 G/SEC no…

0
Default Ð Awarded
Dave Mobile Technician
Ohio
Dave Default
 

I would watch the TC pid and the O2 pics while the condition is happening. It kind of stinks to a lean condition. Under light load and minimum throttle the system is really stressed , both ignition and fuel delivery . The leanest cylinder will always misfire first.

0
Default Ð Awarded
Craig Technical Support Specialist
Illinois
Craig Default
   

Hello Phil I am not sure how to attach a file but if you look in previous posts I asked about a book by Mac Vanderbrink called exploring combustion through the eyes of a scope a generous individual uploaded a digital copy feel free to download it it clears up a lot of mystery in secondary ignition waveforms. diag​.​net/u/ufoundere5wk…; Hopefully that link works

+1
Default Ð Awarded
Michael Mobile Technician
Utah
Michael Default
   

Phillip, Just wondering if the spark plugs are the proper brand and design. You may want to try lowering the gap to experiment. The cure for my Ecoboost was Bosch Iridium plugs. I also used Dielectric grease to prevent leakage and new boots. The spark wanted to go around the plugs instead of through the chamber. I was getting carbon tracking on the plugs most noticeable when going up grades.

+1
Default Ð Awarded
Helpful
Richard Technician
New York
Richard Default
 

Can you road test it while either you or a helper monitor the cylinder contribution. You might be able to spot the cylinder dropping off very quickly and be able to narrow your focus. Another thought would be to scope the coil currents, all of them, and one primary to use as a reference while on the same test drive. I would put a lot more time on the screen than you were using last time. I like…

+1
Default Ð Awarded
Greg Technician
Washington
Greg Default
 

Has the vehicle relearned it’s misfire monitor yet? Sometimes after clearing the codes you have to drive on freeway and decel. W/o touching brake to enable misfire counter. Monitor TCC slippage also. Maybe apply brake slightly when happening. Just enough to turn on brake lights.

0
Default Ð Awarded
Hophy Diagnostician
China
Hophy Default
 

From the waveform of primary ignition, the turbulence at fire line, it means the combustion is not good. it could effected by air/fuel ratio, spark, etc. From my techinical point of view, you shoud compare all the cylinders ignition waveform. If they the same, the problem should be air/fuel mixture or intake/exhaut system. if only habben on #2, ithe problem should be at spark plug or ignition…

0
Default Ð Awarded
Tony Owner
Illinois
Tony Default
 

I also agree with George, #2,3,and 4 looks like problem is internal to the cylinder with lean spikes. Just an opinion

0
Default Ð Awarded
Mark Technical Support Specialist
Washington
Mark Default
 

By the waveform and your description of the concern: warm car light throttle loaded in 2nd and 4th. I have seen this many times and it is a missfire caused by the ECU going into MPG mode and running very lean. Normal operation but the very lean condition puts extra load on the ignition system. This is ussually coils breaking down or the boots failing and the spark jumping to the block or valve…

0
Default Ð Awarded
Phillip Diagnostician
Alaska
Phillip Update
 

UPDATE: Using the snap on verus pro. I Checked mode 6 misfire data before test drive, during test drive twice & after test drive. While never shutting the vehicle off. All 6 cylinders read zero counts of misfires. I recorded air/fuel sensors, & short/long term fuel trims. Fuel trims never went past +/- 5% during stumble event. Air/fuel sensors were reading around +/- 200 mA. (I don’t…

0
Update Ð Awarded
Jason Technician
Colorado
Jason Default
 

Hi Phillip While reading the many responses to this post one question kept sticking out in my mind. Is it possible that the code C1137:64-60-Reverse Gear Switch is sending signal at incorrect times and the programming strategy of the module is freaking out and causing converter lock up at inappropriate times, possible causing a stumble? I know its a wild, far fetched theory, and there is…

+1
Default Ð Awarded
Helpful
Phillip Diagnostician
Alaska
Phillip Default
 

In hind site that is a good theory but the vehicle has been solved... I believe and is now gone. But that is going to be going my notes as something to consider if I get another ford with this problem.

0
Default Ð Awarded
Phillip Diagnostician
Alaska
Phillip Resolution
   

Last update: So what I did was get to the transmission connector and de-pin the TCC. I then wired up a test light to the TCC pin. For safety reasons I put a fuse inline so in case if something worked loose or anything went wrong that the fuse would blow at the battery. I then test drove the vehicle and to my surprise the shudder was gone. I then drive the vehicle several more times while…

+2
Resolution Ð Awarded
Helpful