Tuning open loop?

[Febs]

Hi all,

Had another 02 die on me (though this one should be covered by warranty), so I'm considering doing away with them and getting it tuned open loop.

I know a few here have done it with their LS1s before...just a few questions if you wouldn't mind. :)

- How much more fuel on average do you use?
- Does it require an entire re-tune, or is it just a simple setting change? (Car is already mafless-tuned)
- Do you just leave the 02's in there to plug up the hole, but leave them disconnected?

Thanks guys, appreciate any advice. :)

Cheers,
- Febs.

[Duffman]

I ran my old VYSS open loop after becoming tired of replacing dead O2 sensors. There was maybe 1L/100km fuel increase max. Well worth never having to replace the bloody things again IMO. I can't really remember how much work needed to be done to the tune... Sonny sorted the whole lot out and I didn't ask. And I think the sensors themselves were just left in place all hooked up just not being used.

Hope that is of some help.

[VYII]

Why were you burning out sensors to begin with? Just unlucky/bad bunch etc??

[Delft Maloo]

you can just unplug the sensors and that will force the car into open loop. Depending on how close your tune is will determine the fuel usage here.
Alot of tuners will tune the maf and ve table to be very close ie 4% or better error and then let the o2 sensors make the fine adjustments in closed loop and this works very well mostly.
If your ve/maf is tuned very well(less than +- 4% afr error) than there will be little difference seen or felt.

[VooDoo]

PLug in a WB02 and log the fuel trims for a few 100 k's then apply the changes to the VE table. The more you log the closer you will be. My Adventra is 100% open loop and never have a problem

[Febs]

Why were you burning out sensors to begin with? Just unlucky/bad bunch etc??

Old Pacies - seems to be pretty common with them. This one (right-hand side) has died a lot earlier than the others though, so there's a good chance it's defective.

you can just unplug the sensors and that will force the car into open loop. Depending on how close your tune is will determine the fuel usage here.
Alot of tuners will tune the maf and ve table to be very close ie 4% or better error and then let the o2 sensors make the fine adjustments in closed loop and this works very well mostly.
If your ve/maf is tuned very well(less than +- 4% afr error) than there will be little difference seen or felt.

Thanks mate. I unplugged the sensors a while ago and the car ran fine - a little more fuel than normal, maybe 2l/100km, but apart from that it idled and went like normal.

It's running ridiculously rich with 1 good and 1 bad sensor at the moment, so I'll probably just unplug them again until the mob I bought them from re-opens.

Thanks all. :)

Cheers,
- Febs.

[SSUte01]

Hi all,

Had another 02 die on me (though this one should be covered by warranty), so I'm considering doing away with them and getting it tuned open loop.

I know a few here have done it with their LS1s before...just a few questions if you wouldn't mind. :)

- How much more fuel on average do you use? Should use no more because the car should have been tuned in Open Loop to begin with in order to accurately model airmass
- Does it require an entire re-tune, or is it just a simple setting change? (Car is already mafless-tuned) Again, no changes required, simply unplug one or both O2s and that will force a GenIII inot Open Loop
- Do you just leave the 02's in there to plug up the hole, but leave them disconnected? This works or a bung if you are so inclined,

Thanks guys, appreciate any advice. :)

Cheers,
- Febs.

My opinions in bold. FWIW Open Loop tunes can actually yield better than Closed Loop tunes in terms of economy for a number of reasons namely tolerence in factory sensors for a start and ability to have greater flexibility in how the tune is set up Open Loop. Each has method has pros/cons or you can even go for a hybrid set up if you wish, but I don't see any issue if you choose to stay with Open Loop.

If you are worried and to bring that 2L increase back to level perhaps you could get your tuner of choice spend a short time logging data and touch it up because there really shouldn't be in vicinity of 10% or more (assuming ~20L/100km avg) increased fuel useage IMO simply by going Open Loop, running with dead sensors or unbalanced ones then absolutely, but otherwise, no.

Good luck :)

[Febs]

Cheers guys, great advice. :)

I'll disconnect them and see how it goes on fuel - the 2l/100km was just from memory, could have been less (avg is usually 13.5l/100km).

Cheers,
- Febs.

[myvyss]

So how did it go? Any success with it?

interested to know

Steve


Cheers guys, great advice. :)

I'll disconnect them and see how it goes on fuel - the 2l/100km was just from memory, could have been less (avg is usually 13.5l/100km).

Cheers,
- Febs.

[Febs]

So how did it go? Any success with it?

interested to know

Steve

Sorry mate, should've written back. I unplugged them and it ran a bit more rich than normal - using 1-2L/100km more than usual, but the idle was smoother (smoother than when one of the sensors was busted, not smoother than normal).

Cheers,
- Febs.