I love diesels because they are simple creatures.
More fuel = more power.
Less fuel = better MPG
Too much fuel = smoke » add air
My last (no trailer) tank was 19 MPG. No cat, 15 yr old (hollow) muffler.
I upped the pump till it smoked, then added boost (air) to clear it.
167K miles and still pulls that beast up hills with the rare downshift.
Julien's problem is he added air but no more fuel. The TDI simply adjusted the metered volume to match the airflow and load. Now, had he installed bigger injectors the outcome would be vastly different.
Diesels don't work off of a 14:1 ratio, nor do their computers attempt to maintain any set mixture. More pedal = more juice.
Go to
Fred's TDI Page. TDIClub.com. VW TDI Enthusiast Community and look through the more power section of the FAQs. See much mention of bigger air passages??? Raising the boost is only to control smoke, to burn the extra fuel that you have added.
The inverse reason is why EOC is of little benefit. The engine nearly cuts fuel when coasting. DFCO? WWII diesels had it. Years back a trucker told me it took less diesel to low idle for half an hour than it did to start back up.
Sorry, where were we...... oh yeah.
Bottom line, diesels are very different from gassers. Or before someone nitpicks, injection ignition engines bear little resemblance to spark ignition engines.
