negative LTFT both banks -13,-14 constant ?
 

hello guys ,
:confused:

So I have been dealing with vacuum leaks for a while LTFT high both -/+ so i TOOK care of the following items :
(vacuum system re-done al fixed ) , leaky AOS (replaced now ), new FPR , new upstream 02 sensors both banks , new spark plugs , new MAF sensor , bank 1 intake gaskets replaced , oil fill tube replaced
several smoke test - last test no more leaks as of now.

I m down to the "evap purge valve" - read somewhere that maybe staying open causing air/fuel mixture issues !!!!!

last night got my car running after a while seems to idle and run pretty good however bank 1 LTFT - 13 bank 2 LTFT -14 WTF....

both banks upstream sensor voltage fluctuating pretty good , I m afraid soon or later MIL will come back and emission components 2 of still not completed test so waiting for them to be completed so I can the inspection..

help a brother out here what else ?

:cool:

what tool are you using to get the data? using a porsche tool you should get two readings:

FRA which is the closed-loop load value and is a number that can be between 0.7 and 1.32 before you get a code.

RKAT which is the idle value and can be between +/-4% before code.

vacuum leaks will usually impact idle before load as the small amount of air has a bigger impact when idling than when at load sucking in a lot of air.

load trim issues are often due to fuelling.

bad sensors (o2, maf) can get you too.

... and did you disconnect the battery to reset the trims after doing the work? otherwise they will hang around a while.

i got that data using ICarsoft PORIII

although I also have durometric which I can also pull the data using it .

MAF sensor and 02 new ones too .

also before the last rive cycle I had deleted the MIL since then I have completed 7 components for the emission test - hate to reset everything and start getting it ready again.!!!!:)

planning to take it for smog test / emission test here in TX in about an hour or so is past due two months now.

Years ago when dealing with a bad MAF sensor I saw something that may be similar. I replaced the MAF, cleared the codes and fired up the car while watching the Durametric fuel trims. To my horror they were out of range. I thought I wasted a bunch of money. It took many minutes of running at idle for them to settle out and the engine to run smoother.

The lesson I learned, is anytime after to clearing the codes let the car idle for a while before driving it. I'm not sure what your timeline looks like, but this is something to consider.

I did DO that let it idle for a while several times, fuel trims specially LT were pretty good till I drove back and forth to work and the gym - I have also noticed at increase speed higher RPMs LTFT are as high as -17 on Bank 2 and bank 1 -15 ALWAYS banks around 2 % points difference.

I m thinking there may be a chance on the 02 sensors not reading right perhaps !! so swapping the upstreams sensors from bank1 to bank2 really curious if BANK 2 MAY STILL BE HIGHER OR NOT

AND also just got the evap purge valve - replacing bank 1 intake gaskets since that has to be removed anyways to get to the valve .