swarthyfellow

Hey so I was going over my car data and it would seem that the long term 1 is always higher then long term 2 at all rpm and loads by roughly 5in the positve. The short terms also don't match with short term 1 being 5-10 more in the negative then short term 2. sample: (LT1,LT2,ST1,ST2) (9.3,5.6,-12.6,-3.8) any thoughts...

cliffyk

How many miles on the car, how many since you bought it?

Have the front O2 sensors ever been changed?

What sort of driving do you (miles/year, miles per average trip)?

Any mods, if so what are they?

swarthyfellow

bought the car with 122.5k and i have just under 149k now and that was 3 years ago. I have swap for 2004 heads and intake manifold, CAI and k&N, 75mm throttle/plenum, short tube headers. The rest of the exhaust is factory. I am using sniper performance SF. I would doubt the o2 have been changed. Most of time i drive is around a 40 mile round trip, but most of my mileage has been the 6 trips back and forth from school in ohio to home in Nh.

swarthyfellow

I would imagine the most probable cause would be the o2 sensors? I'm gona check and clean the connection when i get a chance. Would i be able to check their output when they are cold? If they are bad what would be a good replacement? I have to change the oil this weekend so i'll most likely do it while i'm under there. Any other idea's would be great.

cliffyk

Nope, they will have no output when cold, they have to be heated to at least 350°C (662°F) to produce any output--if you want to test them here's how.

Many will assert that only Motorcraft replacements should be used--however I have never, on any vehicle (in over 20 years), had a problem with the Bosch sensors that are available at almost all FLAPS.

swarthyfellow

In sniper performance there is a option "rear o2 present" is that asking if there is o2 sensors or if there is a set before the cats and a set after the cats.

tbirdscwd

The rear 02 sensors don't have have anything to do with your trims as far as I know. They are solely to tell the computer if the catalytic converters are working and if not, they trip the CEL.

Try switching the front 02 sensors from one side to the other. Then disconnect the battery for like 10 min to reset the KAM. After you do that, drive the car and do some datalogging and see what your trims look like. The fuel trims will show the opposite of what they are now if the sensors are the problem. If they are not the problem, maybe one of the injectors is clogged.

What do you think cliffy?

cliffyk

That setting disables the catalytic converter efficiency monitoring by disabling the rear O2 sensors and the heater circuits.

It has nothing to do with fuel trims or any other aspect of engine control.

Have you modified the MAF and/or injector selection, or any of the fueling related settings in SF?

swarthyfellow

MAF and injectors are stock... i have changed fuel and timming settings

cliffyk

What changes did you make to the fueling, which settings (Global PT/FT, rpm based), and by how much?