Hi everyone. I've been having an issue with very long term high fuel trims on both banks. In the 22%+ area.
Changed out the MAF last week, and it helped EVERYTHING. from idle to acceleration.
But bank 1 is still a touch high. In the 6%+ area. Bank 2 is usually around 0 to -1.
While the acceleration bog isn't nearly as noticeable, it is still there to some extent. Especial going up big hills. I don't know if it's normal to lose 2-3 MPH when lugging up a hill or not?
Anyway, here is the list I have done to this 2001 F150 Screw 5.4l:
Had motor rebuilt
Changed fuel filter
Brand new COPS and mc plugs
New air filter
New pcv valve
Cleaned throttle body (BIG improvement here!)
Checked TPS with DMM and my scanner
Smoke tested for vacuum leaks (found and repaired two small ones)
Changed all O2 sensors (truck doesn't have cats)
Changed fluid in transmission
Stock intake with Gotts mod
Rousch exhaust

At this point, I believe all that remains is fuel injectors causing a small lean condition on bank 1. One of them went bad causing a bad misfire when they were finishing up the rebuild on the motor, and they said it looked really bad.
No codes are being set. All tests have completed. Transmission shifts fine with no torque shudder.
Am I on the right track? They were cheap on eBay, I got a set of Ford oem rebuilds for 79 dollars and they are on the way now.
Anything else I can check?

 

Have you tried a few Techron treatments in the gas?

 

Hi glc,

I have. I actually have a bottle in there right now. It's the second treatment in a couple months.

 

I doubt you will ever get both banks the same for all the effort.
It does not make much difference being that close.
The system has the built in range to work over so a small difference is of no consequence. It's called dynamic adaptation built into the system to account for wear and changing conditions.
I would however change the IAT sensor if it shows a tendency to be near either the high or low limit for 'resistance' reading because it has an effect on fuel, ignition timing..
Check the hot running temperature. Should be 195 +/-.
Do these checks with a scanner.
Good luck.

 

Thanks Bluegrass,
I kept an eye on my IAT PID on the 30 mile drive to work today, and it stays right around the outside temperature. You're saying it should get around 195?

 

No, coolant temp should be 195 - IAT should be as close as it can to ambient.

 

Alright glc. I'm confused lol.
Bluegrass says 195+/-
But I don't see how it could go that high sitting in air intake.
My coolant temp has gotten as high as 204, is that not correct?

 

My knock sensor reading varies from 15-40 per trip. Could that be retarding the timing?
Don't know enough about the knock metric to understand what it's telling me.
I'm not sure if that's a normal or high reading.

 

Bluegrass is talking about CHT at 195, not IAT.

If you think your knock sensor is kicking in too much, use higher octane fuel.

 

Thanks glc.
I am not sure if it's too high or not. It's around 47 on the knock sensor pid.
My timing is only advanced a couple of degrees as per the photo in my above post. Could that be the reason the motor acts so weak?

 

What your seeing is about normal. The engine does not run totally knock free at all times but varies a small amount with engine loading, EGR on and off etc.
The sensor is a crystal that generates a voltage proportional the knock intensity it detects from the block location. This signal is fed to the PCM as an analogue signal then converted to digital to add retard to the timing in small increments until the knock is gone, then restores the timing to normal for the conditions at that instant.
If it is present and you watch the timing retard then assume it is active to some degree.
.
Here is a hint. Watch the timing when in OD at about 55 to 60 mph under very light throttle. You should see the timing advance into the 35 + degree range indicating the EGR has been commanded to open. The normal result of this is to advance timing and lower fuel injection amounts as it was designed to do.
.
The coolant temp should be in the 195 to 200 range.
The intake air will vary depending on the ambient and how fast your driving because the intake system also gets heat from the engine bay especially at a stop or idle.
A cooler running engine will run a bit richer from either ambient or coolant system temps. This tends to make a bit more torque but you have to pay for it in fuel consumed.
If you have no codes the PCM self diagnostics does not see any system it tests as out of limits however it does not mean nothing could be improved.
This is where looking a live data gives an advantage.
Most often if there are no codes you live with what you have.
Now if say a large change in tire size was made, torque falls off and fuel mileage goes down, there would be no codes but your drivability would still suffer if for no other reason than your foot gets closer to the floor to keep the power up from loss of mechanical torque compared to what it was before the tire diameter change.. That uses more gas.
Good luck.

 

WOW.
That displayed a very deep understanding of the system, Bluegrass.
Thank you so very much.
I will look at live data as you suggested.
Thanks again Bluegrass and glc.

 

Just to follow up with Bluegrass's hint, the timing did indeed advance at 55 mph and light throttle.

Thanks so much!

 

I have a follow up, and some good news!
Changed the injectors this morning when they arrived. My long term fuel trims:

 

Can I have your old injectors?