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Did it run any different with the MAF disconnected? Do you happen to have an android phone? The ELM327 bluetooth scanners actually do a really good job of scanning data and you can screenshot record video of the scan. $5 on Amazon and you would not have to do all the data manipulation.
Your data indicates the ECU is increasing fueling over time, the question is why. The O2's are telling the ECU the engine it is getting too rich, but it keeps going anyway. I have never seen this, only possible explanation I can think of is a bad temp sensor, have you scanned that? As an engine warms up, it needs less fuel to stay at Stoich, so if yours thinks it is still cold but getting warm, the AFR would start going up.
Pull your plugs and see what color they are, Also, the reason I recommend a road test is because it is easy for an engine to run too rich at idle, but it is hard to do so once the engine is consuming significant air.
Also, plot the TPS and lets make sure it isn't changing at idle.
Having, what I believe to be, a better understanding of the foxwell data files. Here are the data graphs that I believe are now correct. I am unsure of the O2 sensors and how they are suppose to perform. Clearly Bank 2 S1 is not working, but I am not sure yet on how to read the other 3 as of yet.
I have been wondering about what would cause your engine to trend rich as it continues to run. You can see the clear line where it shoudl be kicking in to closed loop operation but instead yours head straight up to 1v, indicating that the Engine is running richer and richer. I am wondering if you might have leaking or sticking injectors, you can test them by removing them and turning the engine over or jumping the relay so the pump runs.
The front O2 sensors should have a steady pulsation between .1 and .8 or so volts. Both of yours are not reading right, but that could be a byproduct vs the issue
Also, your MAF sensor scale/units is wrong. Set the scanner to display/read the MAF as grams/second. A functioning maf should read about 5-9 g/s at idle, and when you stomp on it, upward of 250 g/s
I dont understand what that graph is showing, but it shouldn't be that
Thanks for the replies, they help with the thinking / diagnosis. I found a thread from 2011 where both O2’s were in open loop running rich and the code was no heater activity. Similar to my issue, the culprit was oil dripping into the O2 connector and shorting out the heater elements. As this truck had leaking valve cover gaskets that seems a viable possibility to be my issue as well. I will order 2 more front O2 sensors, clean and seal the connectors and replace the O2 sensors, one then the other. If I get a normal respons from the first one I replace I will move to the second.
Thanks for the replies, they help with the thinking / diagnosis. I found a thread from 2011 where both O2’s were in open loop running rich and the code was no heater activity. Similar to my issue, the culprit was oil dripping into the O2 connector and shorting out the heater elements. As this truck had leaking valve cover gaskets that seems a viable possibility to be my issue as well. I will order 2 more front O2 sensors, clean and seal the connectors and replace the O2 sensors, one then the other. If I get a normal respons from the first one I replace I will move to the second.
I had this years and years ago before I started wrenching myself.
Ok, so tonight I got it to run for >10 min before I shut it off. So at the moment it seems I have solved the first issue of it stalling after 5 Min. I expect I was on the right track a few weeks ago. I had my sons truck in my workshop and thus the lift was being used, so I replaced the O2 sensors and the Crank position sensor (CPS) in the driveway. Well the CPS was faulty / intermittent out of the box. It has a gap between the screw mount and the body, the mounts cracked when I was installing it. Was not apparent then, but when I removed it it was obvious. The second issue was the O2 sensors... I did not get the plugs seated fully. I was going to replace the O2 sensors again and when I started to remove them the plugs being loose was obvious. Much easier to access when the truck is 4 feet off the ground vs. you laying on your back on the ground.
So next my issue is a coolant leak when it comes up to temperature. There appears to be something on the transmission belhousing, passenger side ~2" above the orange bank 2 upstream O2 sensor. It is a small box with at least one hose going to it. That box is leaking coolant. In the photo, this is the passenger side, you can see the exhaust, Air injection and the orange 02 plug. The red arrow is pointing to where the leak is coming from. Hard to get a camera and good light in there.
I will go relax this eve and be satisfied I believe I solved on major issue on the truck.
Last edited by myD2HSE; Feb 2, 2019 at 10:12 PM.
Reason: Add photo
Check your heater core hoses. It also may be a head gasket failure. Since you just replaced the spark plugs, I'm sure you would have noticed if #8 was steam cleaned, which is good news if it turns out being the head gasket.
Check your heater core hoses. It also may be a head gasket failure. Since you just replaced the spark plugs, I'm sure you would have noticed if #8 was steam cleaned, which is good news if it turns out being the head gasket.
Thanks for the reply. I understand it is hard to share what I see in person in a forum post. I do not think it is the head gasket as I can see the coolant coming out of this small box in a steady stream. I am not sure what this is exactly, but it is obvious enough to not be a head gasket leak. Now I may find I am leaking out the head gaskets as well, but this leak is prolific and not the head gasket. These two photos show a bottoms up and top down view of where this part is located. Anyone have a guess as to what this is?
