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I have a 2004 F250 4x4 with the 5.4L Triton in it. I got a tuner when I got the truck to be able to read engine codes and keep on eye on some PIDs. That being said the truck is stock, not running any sort of tune. I got in the truck this morning and noticed some really high readings for ISC Trim and STFT B2. The ISC Trim was in the 65,000 range, and the STFT B2 is in the 20,000 range. Bank 1 is at -99%. The ISC Trim sits there with a closed throttle, but during normal driving will drop into the 100s.
This is a new to me truck and I have noticed some rough idling, poor fuel mileage, and a tendency to run rich. I havent done anything other than regular maintenance. Are these just bad sensors, or is this indicative of a bigger issue that needs to be resolved. If any more information, PIDs, or behavior is needed I am happy to provide extra info. Any help is greatly appreciated!
Edit: Bank 1 was actually for LTFT. Here is a bit more info on the PIDS:
ISC Trim: 65000
LTFT B1: -99.2
LTFT B2: -99.2
STFT B2: 25.5K
LOAD: 17.9
Throttle: Closed
Last edited by Turns_Like_A_Bus; Feb 22, 2024 at 06:22 PM.
I am limited with the tuner what I can see. I will have to see if my other scanner will give me misfire counts and all of that. I have been suspect of a misfire for a while now but it doesnt misfire enough to turn on the CEL. I saw a guy do a card test on his exhaust that was misfiring and mine looked about the same when I did it.
Since there was no CEL it completely slipped my mind to check and see if there were any codes. The only code I could see was a P1000. Also I would like to clarify since I had an error in my original post. I only have a PID for STFT B2 the other PIDS were LTFT.
Use Forscan to have the most troubleshooting options. Another cheap easy App is Torque Pro (paid version) and the extended Ford PID list in that app. It will show misfires.
Thanks for the insight. Come to think of it, I cleaned the Throttle Body when I got the truck some months back. I cant remember if I did the IAC or not, but I feel like I did. I remember having to work up by the firewall.
Regardless, I picked up a new one because I got it on sale and wanted to rule it out. If I did clean it it, there is a chance I'm in the same boat you were.
I going to look further into the scanners to see if I can get better diagnostics.
I will keep you guys up to date. I probably wont be able to get to it until this weekend.
This is Torque Pro on my 97 Econoline. I don't monitor STFT because they look normal. The only problem with this app and Forscan is they don't show cylinders #9 and #10 on my V10 but the total misfire counts adds misfires from those two. I use the app (on my phone) on long trips to spot check things.
A little more to the puzzle here. I still havent gotten enough time to look further into the other items, but I was playing around with my tuner a bit more to see if I could squeeze anymore information out of it. As luck would have it, it had an update that I didnt apply. This had an emissions readiness test built in. The data is not super helpful with the why, but it stated that there were issues with my o2 sensors.
It also claims no misses, but I plan to get actual data on that.
I did look at my o2 sensors and I could only find 2 upstream. There are no sensors downstream that I could see. I am not sure why it marked these sensors as failing though. It does not provide any data if it is a bad sensor or something wrong with the CAT or muffler. If I am understanding the part correctly these are heated o2 sensors so if the heater failed and the sensor had an issue that may imply the sensors themselves failed?
Last edited by Turns_Like_A_Bus; Feb 23, 2024 at 01:49 PM.
Thanks for the information. That would make sense. These particular PIDs are a bit out of my depth, but I am doing my best to keep up and learn. Does that apply to the ISC Trim as well, or would that be mostly for LTFT & STFT? The reason I ask is now the ISC Trim is behaving a bit differently. It still reads 65K but now it is getting other values as well intermittently like 1 not 100.
After hearing that the computer was probably calibrated for OBD1, I decided to spend the day forging ahead with some neglected maintenance. The first was the plugs and second was the IAC. I cannot express how much smoother the truck is running. I am also glad I checked because cylinder 2 was a problem waiting to happen. It was only in finger tight. Cylinder 8 was extremely corroded. Here is a pic of what the plugs looked like at 80k and change on the clock.
Last edited by Turns_Like_A_Bus; Feb 24, 2024 at 03:52 PM.
