When does the ECM go into open loop???
Thread Starter
Le Mans Master
Joined: Sep 2001
Posts: 7,928
Likes: 1
From: More cowbell...
St. Jude Donor '04
When does the ECM go into open loop???
Is it at 100% TPS??? I am just starting to delve into this, and did a quick little test run after I got my ALDL cable working.. my car doesnt seem to go into open look at 100%TPS however.. I was only at 100% very briefly, so that may have something to do with it too. (gonna be LOTS of questions from me over the next few days! ;) )
-Mark
-Mark
Safety Car
Joined: Apr 1999
Posts: 4,623
Likes: 2
From: Ohio
Re: When does the ECM go into open loop??? (MarkLT1)
Mark, to state the obvious, the computer starts off in open loop. After the O2 tells the computer that it's warmed up, then it's in closed loop adjusts the the AFR to as close to stoich as possible.
Pro
Joined: Jun 2000
Posts: 686
Likes: 0
From: Crystal Lake, IL USA
Re: When does the ECM go into open loop??? (MarkLT1)
Read the PCM tutorial here:
http://para.noid.org/~lj/
Has a good explanation of LT1 open loop vs closed loop. Nice 9" Camaro, too.
http://para.noid.org/~lj/
Has a good explanation of LT1 open loop vs closed loop. Nice 9" Camaro, too.
Racer
Joined: Mar 1999
Posts: 292
Likes: 0
From: Vienna VA
Re: When does the ECM go into open loop??? (MarkLT1)
I was confused on this topic, too. There is some misleading literature out there that says that says that at Wide Open Throttle (WOT) the engine goes into Open Loop. 100%TPS would certainly be WOT. Actually, the ECM goes into Power Enrichment (PE) mode, which I believe is similar to Open Loop (no feedback from the O2 sensor is used). Do not know about other years, but for my ECM there are separate tables for Open Loop and PE.
I am still in the Blockhead Learning Mode (BLM), so confirm for yourself :)
Carl
I am still in the Blockhead Learning Mode (BLM), so confirm for yourself :)
Carl
Thread Starter
Le Mans Master
Joined: Sep 2001
Posts: 7,928
Likes: 1
From: More cowbell...
St. Jude Donor '04
Re: When does the ECM go into open loop??? (Carl90)
I was confused on this topic, too. There is some misleading literature out there that says that says that at Wide Open Throttle (WOT) the engine goes into Open Loop. 100%TPS would certainly be WOT. Actually, the ECM goes into Power Enrichment (PE) mode, which I believe is similar to Open Loop (no feedback from the O2 sensor is used). Do not know about other years, but for my ECM there are separate tables for Open Loop and PE.
I am still in the Blockhead Learning Mode (BLM), so confirm for yourself :)
Carl
I am still in the Blockhead Learning Mode (BLM), so confirm for yourself :)
Carl
-Mark
