1999 S70 GLT. Long term fuel trim question

[z80]

Hello!

The car is 1999 S70 GLT. I've been diagnosing another problem while noticed that long term fuel trim stays at 10.94 exactly and doesn't change. After disconnecting the battery it started at around 5. And has been changing between 5 and 7 when some load is applied to the engine during acceleration.

But after ~1 hour of driving it has settled down at 10.94 and it is a perfectly flat line now no matter what I do with the car (idling, high rpm with no load, heavy load rapid acceleration).

Is it normal?

Short term fuel trim changes up and down a little bit even if the car is just idling. But long term now stays perfectly constant. If it matters, I use a simple OBDLink bluetooth adapter.

Blowing propane at hoses and hose connections doesn't make either long or short trim changes.

Thank you!

[454cid]

Is the car reverting to open loop? My 96 would run a pretty steady positive LTFT when it would give up on trying to figure out what was going on. It was my O2 sensor sending a false lean signal.

I'd suggest verifying it's in closed loop, and checking what the O2 is doing.

[z80]

Is the car reverting to open loop? My 96 would run a pretty steady positive LTFT when it would give up on trying to figure out what was going on. It was my O2 sensor sending a false lean signal.

I'd suggest verifying it's in closed loop, and checking what the O2 is doing.

Yes, it is in closed loop at least based on what OBD2 is reporting.
O2 sensor oscillates between 0.1 and 0.7.

It is not the value of LTFT of my concern. It is the fact that it stays perfectly flat and doesn't change even a little bit. It is 10.94 exactly all the time no matter what's going on with the car.

[454cid]

Is the car reverting to open loop? My 96 would run a pretty steady positive LTFT when it would give up on trying to figure out what was going on. It was my O2 sensor sending a false lean signal.

I'd suggest verifying it's in closed loop, and checking what the O2 is doing.

Yes, it is in closed loop at least based on what OBD2 is reporting.
O2 sensor oscillates between 0.1 and 0.7.

Well, that sounds good.

It is not the value of LTFT of my concern. It is the fact that it stays perfectly flat and doesn't change even a little bit. It is 10.94 exactly all the time no matter what's going on with the car.

When my 850 dropped out of closed loop, back into open loop, it would keep a steady and lower fuel trim. I guess after hunting around at 25 plus it would revert to a default.