TooManyIDs

Per the LS1Edit manual, "This table has the estimated Catalyst temperature to go into the 4 Cat cooling modes."

I didn't notice a temp sensor that I could track with AutoTap, did I miss it? If the temp does reach these levels, what happens?

66ImpalaLT1

There is no actual sensor, its estimated based on other conditions. I dont know about autotap, but EFILive Pro can read this value. If you exceed the temps in that table, the pcm will automaticly add extra fuel.

If you have no cats, you can simply disable the COT mode.

Eric

TooManyIDs

Eric,
What kind of "estimated" values are you seeing? Are they getting anywhere near the 830°C threshold?


[Modified by TooManyIDs, 9:22 PM 9/15/2002]

66ImpalaLT1

I havent checked. I just got EFILive Pro on friday, but the car was disabled until just a few hours ago.

Eric

Face

Where can I find this?
Thanks!

TooManyIDs

Face,
I assume you mean with LS1Edit.

Screen before the one pictured above, has a check box. Go to Engine Calibration, then select the "Test Parameters" tab.

Face

Yes, that's what I meant.
Thank you!


[Modified by Face, 11:46 AM 9/16/2002]

kp

So far according to EFIlive my calculated cat temp (I have no idea how they calculate it) hasnt reached 700 degrees yet. COT looks like it kicks in at 750 degrees or so. I'll check my next time on the dyno and see how high the temp goes. I also noticed that the 1st threshold for f-bodies is 40 degrees less then a C5 (99-00 anyhow) so thats why more f-body guys may be seeing overtemp kick in, especially if you start leaning it with a MAFT ot edit.

Oddly enough the 3rd and 4th threshold temps are quite a bit hotter on an F-body then a C5 so who knows. I'm not sure what the threshhold has to do with the actual mixture though..

MattG

Remember to disable the COT if you have removed your cats or it will greatly richen your car at 5500rpm and no matter how much you play with the PE vs RPM table you will not be able to get rid of how rich it makes your car run.. You would lose an easy 10-15rwhp at peak HP RPM range if this COT kicks in.

6Speeder

As per the manual "4 cat". Does this mean that only those cars with pre-cats have this programming? Yes, I am grasping at straws. I'd rather not deal with it. :cool:

TooManyIDs

No, if you look at the table, there are 4 temperature thresholds.

chuckster

[QUOTE]Remember to disable the COT if you have removed your cats or it will greatly richen your car at 5500rpm and no matter how much you play with the PE vs RPM table you will not be able to get rid of how rich it makes your car run.. You would lose an easy 10-15rwhp at peak HP RPM range if this COT kicks in.

[/QUOTE

Well my LS1-Edit is here!!!!
COTS is the 1st thing to go.

Matt I have Gutted CATS and 02 Sims.. But you say that the extra fuel comes in at 5500rpm...I assume the 02 sensors have nothing to do with the overtemp condition and they are only for emisisons..

So I guess I can count on an extra 15 ponies after 5000rpm?

MattG

Only SOME cars seem to be affected by this condition.. I know of a few 2001s that have had it and the COT setting brought back the A/F ratio to where it should be. The rear 02simms are only for emissions.

kp

Just an update on what I stated (I dont like to give bad info on a forum), I dont know what I was looking at a few weeks ago but it appears that the calculated cat temp is not a valid parameter on a 99 C5. It shows up on the list but it says it isnt supprted by my PCM. I was working with a 2001 a few weeks ago and I think it may have been valid on that car (I know I seen 700 degrees somewhere). I was going to get some readings today and it came up as not available on my car according to EFIlive on my car.

I am not sure if the COT even applies to a 99 49 state car since its not mentioned anywhere in the service manual and the parameter isnt supported by the scan tool. Back to square one for me trying to figure out how the PCM calculates cat temp...

chuckster

This response came from Ken Kelly..(aka LS1-Edit GOD)

John,
YOu are right, THe PCM does not measure the CAT temperature, It
predicts it based on engine load, RPM, and time.

Ken

Team ZR-1 wrote:
>
> Since the C5 does not support this COT function with 3way Cats,
> there is no sensor as other Cats have to measure the internal temperture and
> GM OBD-II does not support COT PID
> then how does this table function since its contents has nothing to compare to ?
>
> JR
> Team ZR-1 Consulting Services

TooManyIDs

kp,
Any more news?

kp

I still have no clue how the PCM comes up with the temp threshold for overtemp. My guess is (its just a guess) the people that are having COT kick in are turning off the rear O2s with LS1 edit as opposed to using O2 simms and that may have something to do with it. I always run cats (even when I didnt have cats on my other LS1 cars I never seen COT kick in like some have) and I have my a/f pretty flat now so I kind of gave up trying to find out, someone knows all the details I'm sure but I cant find him/her :)

TooManyIDs

Only two cats on my car (it comes that way) and I haven't touched the O2 sensors.

kp

Are you sure you are seeing cat overtemp or is the car just running rich? Cat overtemp is a pretty sharp change at ~4500 from what I read, I have never seen it firsthand so I cant say. Try turning it off and see what happens with a wideband, I havent seen major changes in my a/f throughout the rpm range and I havent touched the cat overtemp settings. I dont think I have seen anyone having problems with cats on their car still.

TooManyIDs

I've done a lot of pulls. The drop I saw, on the last two pulls only, was from around 12.6:1 at 6,000rpm to about 11.6:1 at 6,400rpm.

It was sudden. Have never seen this before, don't believe it's the PE tables. My table values aren't going richer in either PE table.


[Modified by TooManyIDs, 8:36 AM 9/26/2002]