- Joined
- Mar 9, 2012
- Messages
- 707
- Reaction score
- 4
- Points
- 0
- Location
- Ohio
- Vehicle Year
- 04
- Make / Model
- Ford
- Engine Size
- 3.0
- Transmission
- Automatic
Howdy ya'll! Long time no see.
04 3l 2x, daily driver, nothing crazy. Throws p0420 code.
Testing down stream o2 sensor in hopes that it is bad, not a cat problem (f* you california).
I put it in the vise and heated it up to turning red, hooked up to the DMM between the back (POS) and grey (NEG) on DCV. It peaked out around .3v. The best I can find is that it should peak around .85-.9v.
Backstory, couple weeks ago I washed out the engine bay, next day it started acting up. Quick trouble shoot over the phone and i had the wife push home (couple miles). Upon inspection, it had a couple hard misfires, but on random cylinders. Checked and cleaned everything, threw new plugs and wires at it (was in dire need anyway). No dice, bench tested the coil pack, bad. Had *8* cracks in various locations. New coil pack and she runs like new, after figuring out the plug wire diagram in the book is wrong! Also found a bad idler pulley, so the engine is much quieter now.
30 miles later, starts throwing p0420. No change in performance, getting way better mileage than previous to the whole coil pack fiasco. Engine sounds great, drives very well. Having a CEL is obviously a no-go. Cleared code and it keeps coming back, even wiped the PCM to ensure its not a residual code. Which leads me to trying to test the o2 sensor, because I'm not trying to throw parts at it, but really hoping it's not the cat.
04 3l 2x, daily driver, nothing crazy. Throws p0420 code.
Testing down stream o2 sensor in hopes that it is bad, not a cat problem (f* you california).
I put it in the vise and heated it up to turning red, hooked up to the DMM between the back (POS) and grey (NEG) on DCV. It peaked out around .3v. The best I can find is that it should peak around .85-.9v.
Backstory, couple weeks ago I washed out the engine bay, next day it started acting up. Quick trouble shoot over the phone and i had the wife push home (couple miles). Upon inspection, it had a couple hard misfires, but on random cylinders. Checked and cleaned everything, threw new plugs and wires at it (was in dire need anyway). No dice, bench tested the coil pack, bad. Had *8* cracks in various locations. New coil pack and she runs like new, after figuring out the plug wire diagram in the book is wrong! Also found a bad idler pulley, so the engine is much quieter now.
30 miles later, starts throwing p0420. No change in performance, getting way better mileage than previous to the whole coil pack fiasco. Engine sounds great, drives very well. Having a CEL is obviously a no-go. Cleared code and it keeps coming back, even wiped the PCM to ensure its not a residual code. Which leads me to trying to test the o2 sensor, because I'm not trying to throw parts at it, but really hoping it's not the cat.