Help us help you. By posting the year, make, model and engine near the beginning of your help request, followed by the symptoms (no start, high idle, misfire etc.) Along with any prevalent Diagnostic Trouble Codes, aka DTCs, other forum members will be able to help you get to a solution more quickly and easily!
First post here so I appreciate anyone's time and experience. I have a 2015 Ford F150 with the 5.0 motor. A while back I started noticing decreased fuel efficiency and when I finally hooked up a scanner I noticed some misfires in mode 6 data but not enough to set a DTC. The majority of these misfires have been on bank 2 and normally the cylinder with the most is cylinder 6. When I first noticed this I still had factory plugs and was around 126,000 miles. I figured that was a fairly long life on the factory plugs so I replaced them with the motorcraft recommended replacement. After that I didn't see very much improvement so I cleared KAM and saw a little improvement but then it slowly worked its way back to unfavorable fuel trims and the same bank 2 misfires. I noticed what I thought to be eratic/unreliable upstream o2 sensor data so I replaced both upstream sensors with NTK brand sensors and again very little if any improvement. There are quite a few other things I have checked and done to try and diagnose this but didn't want my first post to be even longer.
What are your total fuel trims? It is the sum of the st and lt of each bank. Those upstream you replaced - are they the recommended replacements from Ford?
Fuel trims are sorta all over the place depending on if it is at idle, deceleration, or under throttle. The upstream sensors are not Motorcraft but from what I found online NTK makes the sensors for Motorcraft.
No I can't think of anything. One thing that is concerning me is when I watch intake and exhaust camshaft shaft data. The data pid is showing differences between actual and commanded degrees.
I replaced air filter, pcv valve, and purge valve on throttle body when I changed spark plugs. Purge valve was leaking by and pcv valve would still rattle but could tell it was dirty. A while after that I swapped ignition coils from one bank to the other to see if the issue followed but it didn't. I have since then replaced all ignition coils. I transferred cylinder 6 fuel injector to the other bank and so far have not seen data that suggests it definitely is fuel injectors but they do make me wonder if they could be an issue. Before the swap I listened with a mechanic’s stethoscope and at that time all injectors seemed to be pulsing in a similar way but I didn’t have anyone at the time to snap throttle or hold rpm at certain levels. I've done scan tool based relative compression tests that have been fine. I've checked for vacuum leaks with a Guage as well as water and carb cleaner.
Another weird thing I've noticed is when I reset the keep alive memory it seems to do great until it starts relearning.
One thing that is concerning me is when I watch intake and exhaust camshaft shaft data. The data pid is showing differences between actual and commanded degrees.
How much difference are you seeing?
Brief differences when the commanded position changes aren't unusual. They'll usually show up as little 'blips' when graphing the difference PIDs.
Steady difference of a degree or more might suggest an issue.
Just to clarify the original complaint, this is all in the pursuit of finding the cause of reduced fuel economy, correct?
There are no misfires or performance issues that you experienced which lead you to look at mode 06, you just noticed counts on individual cylinders while you were looking for the cause of lower than average miles per gallon?
Also, you still haven't answered Bills4065 repeated questions about the fuel trims.
Sorry for waiting on the response I wanted to be back in my truck to confirm. Currently at idle
Short term bank 1 fluctuates between -2.34 to 3.12
long term bank 1 is 3.9
Short term bank 2 fluctuates between -.78 to 3.12
Long term bank 2 is 6.25
That is currently at idle I have had worse and better numbers than that other times at idle.
I can get the 3500 rpm readings a bit later.
Thanks again
As I was typing that last message I had Short term bank 1 dip to -7.4 and slowly rise back to 0
And Short term bank 2 dip to -5.6 and slowly rise back.
Wow thanks for mentioning to check them at 3500 rpm.
On the recording from my scan tool I paused at 3469 rpm.
I'm getting bank 1
long term at 7.03
Short term 10.15
Bank 2
long term 8.59
Short term 31.25
Yes indeed it would. Bank 1 is running 17.18% lean and Bank 2 is 39.84 % lean. The trim numbers you gave us are positive meaning you are running lean on both banks. Bank 2 is running much leaner than Bank 1.
Could that also be because that part of the fuel table hasn't learned since my previous KAM reset?
So just curious how will the fuel pressure test help if both banks are not affected the same? Would that not lead to it more likely being bad fuel injectors since it's at higher rpm?
Again these are just questions I'm curious about because I'm trying to learn more and better my diagnostic skills.
Thanks
I think I see partly where I was mistaken. I was subtracting the long and short term but I should have only done that if one of the reading was negative correct?
Topic Author
