P0478 code no power
Things I've tried this am:
first turbo that was running fine then not. It's got some carbon build up but no so much that it's going to stop running. The action on the actuator moves freely you can hear the air suction of the oil. one I sub in was just cleaned and rebuilt. Don't think it's the turbo vanes
the vgt solenoids I used test 3.8, 3.8, 4.1 ohms. That's in the good range. Guess all 3 could be bad but seems fine.
brand new ebp sensor. Same readings as all the others. And I dropped the down pipe off back of the turbo. Ebp still off the charts wot - 2000 rpms sitting still. Either the pcm us screwed or the problem is in turbo airflow creating ebp to be high
did pull the egr valve. Didn't test it but carbon isn't completely awful. Not caked on.
scoped the intercooler. Oily as you may well imagine but no shop rags or towels in there. lol (never know).
getting to where maybe it's time time to try another pcm.
Last edited by Craig Maffet; Yesterday at 08:27 AM.
because of your willingness to help, I been lending hand on 7.3s where I'm a bit more familiar other venues. Just paying it forward.
anyway, my plus at vgt and at the ebp were skinned one wire each right behind pigtail. New pigtails both. Noticed when u was looking at the 1 month old vgt the base of the valve was visible like it backed out. Removed bracket pushed on it and it pushed itself out. This same vgt was in the other turbo when it went bad. So I pulled it out - it's springs fine, looks brand spanking new still. The spring end was cocked a tad - just enough it was viably askew. Put an old old vgt in it and boom. She worked. I didn't take it out or even jam the pedal yet bc so much to tighten down but ebp dropped from 18-20 to 16-17 immediately.
morale of the story kids. New parts don't mean good parts.
what I didn't realize until today. If you ohm check check the vref against the return signal wire on the ebp-egr-ipc-eot-ect-mat network, every one will report Back a different ohm number. Guess has to do w frequency and wave length something like that.









