Boost
December 30th, 2011, 01:00 AM
'10 Equinox 2.4 has a current P0172 (rich) and running rough with LTFT at around -35. Also has misfire codes, passed and failed and history but that is related to the excess fueling in my opinion. All the other readings seem fine (MAP /MAF / TP) and I checked for vacuum leaks including the filler neck and dipstick area.
When I reset the fuel trims, it runs perfect for a few seconds before it goes rich again (!).
One thing I noticed is the Commanded EVAP purge is 11% at all times at idle. Not sure if this is normal, I know it runs tests but even after the Evap Purge test status is complete and ok, it still commands the purge to 11-12%, and increases with revs. Not knowing what else to do, I blocked off the Purge to the engine. When I reset the trims, it did not return to as rich as before (around -29, -28). Reset the trims again, and once more, it improves the LTFT it settles on ( low -20s ). A few more times and we are within normal range (-15 or so ).
?????
One thing I plan on is comparing a similar vehicle if I get a chance today for the commanded purge at idle, as well as the trims. Please give me your input / thoughts on this! Thanks!!!
When I reset the fuel trims, it runs perfect for a few seconds before it goes rich again (!).
One thing I noticed is the Commanded EVAP purge is 11% at all times at idle. Not sure if this is normal, I know it runs tests but even after the Evap Purge test status is complete and ok, it still commands the purge to 11-12%, and increases with revs. Not knowing what else to do, I blocked off the Purge to the engine. When I reset the trims, it did not return to as rich as before (around -29, -28). Reset the trims again, and once more, it improves the LTFT it settles on ( low -20s ). A few more times and we are within normal range (-15 or so ).
?????
One thing I plan on is comparing a similar vehicle if I get a chance today for the commanded purge at idle, as well as the trims. Please give me your input / thoughts on this! Thanks!!!