MAF Open Loop

[NewV]

Ok so I'm happy with my VE now. I want to check it out with the MAF re-enabled but no NBO2 as I still have one disconnected for the WB.

If I reflash my original tune with the new VE table but max out B4205 temperatures will I stay in Open Loop but out of speed density? MAF is still plugged in.


Will I get STFT and LTFT without Closed Loop? I don't think so but want to validate.

[SSpdDmon]

If you maxed your closed loop temp enable table, you'll still be in open loop when you plug your MAF back in. Don't forget to re-enable any codes you killed for the MAF and make sure your LTFTs are [still] disabled.

SD vs. MAF influenced fueling isn't associated with closed/open loop - they're two seperate things. SD/MAF is on the front end and OL/CL is on the back end. SD/MAF says this is how much fuel the engine needs based on the tables in the PCM.

--Fuel delivered -- Combustion occurs --

OL trusts those numbers in the PCM to be 100% accurate and makes no adjustment to them. CL tries to tweak those numbers based on the exhaust AFR around 14.63:1 (stoich). That's how it's closing the loop...

MAF/SD measures air, PCM looks up values, fuel is calculated & delivered, combustion occurs, the O2 sensors read the exhaust, and adjustments are made as the process repeats (like a loop). OL is more linear since the AFR reading from the exhaust is ignored by the PCM. Therefore, there are no STFT's or LTFT's in OL. You disabled them anyway (or you should have) when you maxed the CL Temp Enable table and switched off LTFT's. ;)

[Tordne]

So if I understand correctly you want to:
1) Take the VE table from current tune (after AutoVE process) and put back i stock file.
2) Set the B4205 table to max values.

That should see you in Open Loop still, correct. Did you make any changes to fueling, PE mode etc that you want to keep?

[TAQuickness]

Why not just take the current tune, re-enable the MAF, plug the MAF back in and go from there?

[SSpdDmon]

Why not just take the current tune, re-enable the MAF, plug the MAF back in and go from there?
That's the short version of what I told him to do. ;)

[NewV]

Why not just take the current tune, re-enable the MAF, plug the MAF back in and go from there?

Because that wouldn't allow me to overthink this :Eyecrazy:

I was basically looking for a way to go back to closed loop w/out the NB but I figured on my own that was not possible. So I then got the 'not so' brilliant idea on the whole Open Loop w/MAF thinking I would still see LTFT. Which I now know is not possible. See this way I'm not overthinking it am I?

Confused yet?

[NewV]

Ok, so if I re-enable the MAF what do you think that will do before I tune it? Force me to run rich/lean or is it anyones guess based on how bad it is set for now?

[SSpdDmon]

What's done to the car?

[NewV]

What's done to the car?

Just a CAI and Catbacks.

FYI: It ran a little lean, about 15.1 AFR average versus my near perfect 14.7 AFR average without the MAF. Same drive to/from work.

[SSpdDmon]

Yeah, if it's just a CAI/catback, it should be within 5%.