$EE Help with strange Closed Loop or PE operation?

[johnny_b]

Looking at my logs Ive noticed something odd. while driving in closed loop mode, all of a sudden the Target AFR will go 12.2:1, and the BLM's will turn off, but $EEHack shows it is NOT in PE mode. There are other points in the log where it shows PE mode is ON, so i don't think its software or datalogging bug?

On my last log it happened about 3 times.

Closed Loop indicator is on, then all of a sudden the BLM indicator goes off, target AFR goes down to 12.2:1, which is normally what it would command for PE mode. However the Closed Loop indicator remains on and the PE mode indicator never comes on. and then all of a sudden it will go back to normal, Closed Loop indicator on, BLM indicator on, target AFR 14.7:1.

I can confirm that the actual AFR is changing because the o2 readings go to 900mV and stay there during these "events".

When I graph the datalog and select the "PE active" overlay it DOES NOT show PE active during these events so I'm very confused. These events last about 30-45 seconds at a time and there is no drastic change in RPM's that would cause this when it happens.


Any advice?

[Terminal_Crazy]

Looking at my logs Ive noticed something odd. while driving in closed loop mode, all of a sudden the Target AFR will go 12.2:1, and the BLM's will turn off, but $EEHack shows it is NOT in PE mode. There are other points in the log where it shows PE mode is ON, so i don't think its software or datalogging bug?

On my last log it happened about 3 times.

Closed Loop indicator is on, then all of a sudden the BLM indicator goes off, target AFR goes down to 12.2:1, which is normally what it would command for PE mode. However the Closed Loop indicator remains on and the PE mode indicator never comes on. and then all of a sudden it will go back to normal, Closed Loop indicator on, BLM indicator on, target AFR 14.7:1.

I can confirm that the actual AFR is changing because the o2 readings go to 900mV and stay there during these "events".

When I graph the datalog and select the "PE active" overlay it DOES NOT show PE active during these events so I'm very confused. These events last about 30-45 seconds at a time and there is no drastic change in RPM's that would cause this when it happens.


Any advice?


There are a couple of "safety" controls in $EE
CAT overtemp dumps fuel in to cool the cats i think & can be turned off or down.

If engine gets hot extra fuel can be added in a table (I forget which one (open loop afr vs temp?))

Hopefully Steveo will probably chime in about now.

[kur4o]

12.2 afr = stock setting for CAT protect AFR.
So you might enter that cat protect stuff. If you don`t have cat turn it off by raising cat protect min coolant temp.

[johnny_b]

Ok this makes sense. I just took another look at the logs, and saw that the cat over temp switch is indeed going to "ON" when this is happening.

What does the ECU use to decide to go into CAT protect mode? its not as if the ECU knows the temp of the CATS directly?

[johnny_b]

Which would you recommend, setting the Cat Protect Temp Commanded AFR up to like say 12.8:1? or raising the Cat Protect Temp for low, med, & high pressure?

My cats are way the hell under the car, near the tail shaft of the transmission, so i really dont know if they're getting as hot as the computer thinks they are.

[steveo]

i would just disable cat protect entirely, and try to run your car as close to stoich as you can. with a relocated cat there's no way it's accurate anyway, and it's so undocumented that it's nearly impossible to tune it back into shape.

[LeMarky Dissod]

There are a couple of "safety" controls in $EE.

If engine gets hot extra fuel can be added in a table (I forget which one (open loop afr vs temp?))
That's the table.
The F-bodies also use 'High Coolant Temp Enrichment' (TunerCAT) or 'Overheat Enrichment' (TunerPro); once a coolant temp is exceeded, a richer base AFR is commanded.

If the F-bodies' coolant temp sensor is located in the head instead of the H2Opump [as in the B-, D-, & Y-bodies], then that at least partially explains why only the F-bodies can properly make use of Overheat Enrichment.

Please excuse the digression.

[steveo]

If the F-bodies' coolant temp sensor is located in the head instead of the H2Opump [as in the B-, D-, & Y-bodies], then that at least partially explains why only the F-bodies can properly make use of Overheat Enrichment.

it's not, though. the sensor in the head is just a gauge sender. the location of the temp sensor for the ecm is the same in an f-body.