General Fuel trims stuck.

[Vince]

What would cause this..

No matter what changes I make to my fuel settings on my
MAF, my fuel trims are ALWAYS Low-100 Mid-100 High-81.
Cruising or WOT they never change from these readings, either.
Every car I've seen, they constantly move around while driving.
Mine are rock solid. Any ideas??

 

[kpt4321]

They take FOREVER to change, it's normal.

When I tune the fuel trims, I always reset the ECU first and then just tune with the O2 trim.

 

[Vince]

Yeah, but Im talking about months and its always the same.
And shouldnt they move when Im driving??
Ive tried different ECUs and its always 100-100-81.

 

[nine5raptor]

A logger issue then? They should be changing. If you reset the ecu, do they reset to 100%?

 

[Vince]

The logger I use gets passed around to three other cars
and I can always see changes with the fuel trims on those
cars.

I've tried different ECUs and within a week I get the logger
on it and its always 100-100-81. I've never reset the ECU
and tried it with the logger right after so I will and report back.

 

[Vince]

Something else I forgot to mention.
When I disconnect my O2 sensor, I wont throw a code.
It's been off for a week now and nothing. The car runs better
without it also. AND, the fuel trims still stay at 100-100-81.
On my old FWD I could unplug the O2 and drive for about
10 minutes and it would always throw check engine.
This is with 3 different ECU's.