Closed Loop vs Open Loop...
Thread Starter
Racer
Joined: Jan 2011
Posts: 393
Likes: 1
Closed Loop vs Open Loop...
I plugged a scan guage into my car today and noticed that it stayed in "closed loop" all the time except when first started...and then it only stayed in "open loop" for a few seconds...
I am not up to speed with GM products coming from a Mopar background....The norm for a Mopar is to stay in closed loop during normal driving and go to open loop anytime anytime driving becomes even slightly aggressive......dont have to go WOT.....just a little spirited driving will make it switch to open...
I never could get the Vette to change to open no matter how hard I drove it.....seems to run and pull hard...is this normal for bow ties??..
I am not up to speed with GM products coming from a Mopar background....The norm for a Mopar is to stay in closed loop during normal driving and go to open loop anytime anytime driving becomes even slightly aggressive......dont have to go WOT.....just a little spirited driving will make it switch to open...
I never could get the Vette to change to open no matter how hard I drove it.....seems to run and pull hard...is this normal for bow ties??..
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Open loop means no O2 control of the fuel.Usually when car is first started cold. Closed loop means O2s are heated up and working and controlling fuel delivery. At WOT the fuel is controled by the PCM not O2 feedback which I guess shows as open loop in a Mopar.
Thread Starter
Racer
Joined: Jan 2011
Posts: 393
Likes: 1
That is what I am saying...it is not going to open loop...GM does not go to open loop during WOT??
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
Burning Brakes
Joined: Jan 2006
Posts: 788
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From: Olathe Kansas
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Racer
Joined: Aug 2005
Posts: 465
Likes: 16
When going to WOT or Power Enrichment Mode. The PCM does several things.
It no longer is concerned with maintaining economical or environmental operations. It freezes the fuel trim adjustments, stops monitoring the O2 sensors, and looks briefly where it was at in “closed loop mode”.
It then starts to rely almost exclusively on the MAF sensor input for proper a/f adjustment.
It no longer is concerned with maintaining economical or environmental operations. It freezes the fuel trim adjustments, stops monitoring the O2 sensors, and looks briefly where it was at in “closed loop mode”.
It then starts to rely almost exclusively on the MAF sensor input for proper a/f adjustment.
Thread Starter
Racer
Joined: Jan 2011
Posts: 393
Likes: 1
When going to WOT or Power Enrichment Mode. The PCM does several things.
It no longer is concerned with maintaining economical or environmental operations. It freezes the fuel trim adjustments, stops monitoring the O2 sensors, and looks briefly where it was at in “closed loop mode”.
It then starts to rely almost exclusively on the MAF sensor input for proper a/f adjustment.
It no longer is concerned with maintaining economical or environmental operations. It freezes the fuel trim adjustments, stops monitoring the O2 sensors, and looks briefly where it was at in “closed loop mode”.
It then starts to rely almost exclusively on the MAF sensor input for proper a/f adjustment.
My concern was that the car was stuck in the closed loop since the scan tool readout showed closed loop no matter how the car was driven...
