A friend of mine has recently had problems with his truck idling and running rough. It's also drinking a lot of gas. This is normally a sign of O2 failure. I scanned his truck and Both o2's are staying pretty flat.
I didn't get any O2 codes but i did get some EVAP codes. Can the Evap solenoid cause O2 reading problems?

Or do you think BOTH sensors went out?

Diagnostic Trouble Codes:
P0102 "Mass Air Flow (MAF) Sensor Circuit Low"
P0443 "Evaporative Emission (EVAP) Purge Solenoid Control Circuit"
P0449 "Evaporative Emission (EVAP) Vent Solenoid Control Circuit"
P0102 "Mass Air Flow (MAF) Sensor Circuit Low"
P0443 "Evaporative Emission (EVAP) Purge Solenoid Control Circuit"
P0449 "Evaporative Emission (EVAP) Vent Solenoid Control Circuit"

 

Is the tune in open or closed loop?

 

it's a stock tune 00 5.3. His maf wires are cut from when the truck caught on fire a while back so that's why the MAF codes

 

Did he get a new harness when it caught on fire and wouldnt start?

 

I don't think so. He just put a new starter on it yesterday and it starts fine now.

 

So the maf is not connected at all? If so did he at least wire in the iat sensor?

 

no. All of the wires that run up to the maf are burned up and just hanging down in pieces.
It burned up several months ago and was fine until recently.

 

What are the trims showing?

 

Sorry i was on my phone before. Looking at the log, you did not let it come up to operating temp so the log is kinda pointless.... Also since the maf is completely disconnected the IATs show -38*s.... Since the maf is disconnected it is running in SD mode. SD mode calculates g/cyl based on this equation. g/cyl = VE*MAP/charge temperature. Charge temperature = 273.15+IAT+((ECT-IAT)*factor). Since your IAT reading are off, your g/cyl will be off, which also means your AFR will be off. More than likely he cooked the O2s. But you really can't tell that becuase you did not let the log run long enough for the tune to switch into closed loop. Table B4205 shows the entry criteria for closed loop. Since your IATs are -38* your need to let it warm up to roughly 184*. Once at that temp the O2 sensor will start switching, then you can see if the O2s are toast...

 

You sure you know what you're talking about corey?