Jump to content
PCMTEC Forums
Roland@pcmtec

HOWTO: Disabling closed loop O2

Recommended Posts

UPDATE

auF0164 LTFT Enable should be all that is required to disable closed loop permanently.

 

Set auF0163 to 4096 degrees. This will mean the O2 sensor is never "up to temp" and hence the O2 logic remains disabled.

image.png.ded9a52967d8dce7a04f041f5eda8d62.png

Or set the delay time to 1000000000 (this is actually clock ticks and not seconds)

image.png.99a755a17ab7fe976ee6c477b03bf5fd.png

Or set auF0162 to 1000000000 for all temperatures.

image.png.cc971dc2d1524691981f3778533b507f.png

UPDATE:

on FGs the best way is to just set the A/D Count to 0.0 on the Open Loop TPS Transition table auF0153 as the above tables have been reported to not work on FGs

image.png.80c9b12f8a561350f7b0bd9452bfa1df.png

 

  • Like 1

Share this post


Link to post
Share on other sites
2 hours ago, fordsrule said:

Does it require to change all the cells in the  A/D Count column, or just the 320?

Thx

Depends what you want to achieve.  Pick the rpm you want to disable it at, and then pick the TPS threshold you want to disable it at...

Share this post


Link to post
Share on other sites
2 hours ago, Roland@pcmtec said:

Depends what you want to achieve.  Pick the rpm you want to disable it at, and then pick the TPS threshold you want to disable it at...

Ok

I've read that this proceedure is recommended for tuning wideband, do you agree with that?

Cheers

Share this post


Link to post
Share on other sites
On 5/17/2019 at 4:34 PM, fordsrule said:

Ok

I've read that this proceedure is recommended for tuning wideband, do you agree with that?

Cheers

The whole point of disabling closed loop fueling is to check if your commanded lambda matches the lambda measured in your exhaust. If you leave it enabled it will be blending at lower rpm so it will be transient and your data won't be useful.

So if you are testing open loop only, you could just set all cells to -100, if you just wanted to make open loop occur earlier (eg a permanent change) then you'd only disable it at the rpm and TPS points you desire and most likely leave a blend still there so the transient is smooth.

Share this post


Link to post
Share on other sites
13 minutes ago, Roland@pcmtec said:

The whole point of disabling closed loop fueling is to check if your commanded lambda matches the lambda measured in your exhaust. If you leave it enabled it will be blending at lower rpm so it will be transient and your data won't be useful.

So if you are testing open loop only, you could just set all cells to -100, if you just wanted to make open loop occur earlier (eg a permanent change) then you'd only disable it at the rpm and TPS points you desire and most likely leave a blend still there so the transient is smooth.

Ahh, i think i undetstand, thankyou for your help once again

Share this post


Link to post
Share on other sites

Not sure the best place to put this. But for now here are some flags you can datalog to diagnose why a car is in open loop

Driver demand:

wot_ol_flg == 1 WOT Open Loop Demanded

 

If any of the following are true ol_exc_flg will be set to 1 which also forces open loop

 

er_ful_req == 1

Engine Running On-Demand testing requires OL

 

ds_ego_ol == 1

Intrusive EGO monitor open loop. This only occurs if abnormal switching is seen on the O2 circuit. Eg lean for an extended period of time. I believe this only occurs for V8s if one bank doesnt match the other bank

 

oltmr > auF2504

Extended decel open loop

 

ppctr > auF12184

Cylinder cut out (rev limit etc)

 

osc_ol == 1

Output state control of LAMBSE (OBD2 tester has requested it)

 

P0152 HEGO Overvoltage

P0155 HEGO Malfunction
 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...