Continued issue when car hits 125 degrees

[LGAFF]

yep, three wires...weird stuff..

[Franke]

Since it looks to be a possible temp problem, there is a chart in the FSM the defines resistance values for the CTS and MAT at different temps. Do you get any codes? Have you thought about replacing the CTS? I know its a PITA.

[XfireZ51]

Its not the O2s or anything like that. You have cams similar to the ones I have and I experience the same stumble right at about 47-50C CTS. It goes C/L there and really doesn't like it until the ECM can adjust. Its also still not "learning" at that point. So basically the idea is to delay C/L a bit further up the temp scale. I have played around w a few parameters and at this point the "stumble" is momentary. It recovers quickly. Have you relocated the MAT towards the airbox?

[scottfab]

Originally Posted by LGAFF

Going lean because of the 02?

Maybe so. I had one that until I began recording data with a datalogger (diacom) I had no clue. It was "lazy". In your case it could be that the heating element is not getting up to temp before close loop is entered. Then eventually get there with exhaust temps.

[QUOTE=LGAFF;181550]A fuel injector is not going to get better, neither is a pump....unless its a relay...primary replaced...I would think if the engine transitions from the secondary to primary the issue would be the primary relay or pump

Pumps can and do fail intermittently. Since your symptoms are so repeatable probably not but....

Originally Posted by LGAFF

if it were the pump....it would not go away

It can in fact go away but not as a function of engine temp.

Originally Posted by LGAFF

the issue lasts 30 seconds then gone

Job for a datalogger and then time to study what happening as the close loop bit is set (close loop entered), focusing on which side maybe going lean. Does this symptom happen in full eng power and not? But anyway.... time for a data capture for the full warm up period.

[LGAFF]

So Dom, are you thinking its possibly not a "Physical" parts failure....but that the engine enters a state of ......wait for it......

"Camfusion"

I need to trademark that word

[XfireZ51]

Originally Posted by LGAFF

So Dom, are you thinking its possibly not a "Physical" parts failure....but that the engine enters a state of ......wait for it......

"Camfusion"

I need to trademark that word

I think Steven Colbert has already copywrited that term.
The ECM goes C/L at that point. I can see it happening w just my WB. Don't need a scan tool. So the stumble is a consequence of the engine control transitioning from O/L to C/L. There are delays built into the calibration which accommodate the stock setup. Change the cams and things move faster becoming somewhat less stable. So the calibration needs to be modified in order to control the motor more tightly in order to control the instability. In doing the tuning I change parameters in order to keep a tighter leash on the motor reaction to inputs. The stock values tend to exaggerate the inputs to a modded motor.
As I have explained at other times, part throttle tuning is more important than WOT. In fact, WOT DEPENDS on how good part throttle is. Partly because we spend so much more time at part throttle than WOT. PT is time and fuel consuming which is why it isn't very commonly done.

[scottfab]

Originally Posted by XfireZ51

I think Steven Colbert has already copywrited that term.
The ECM goes C/L at that point. I can see it happening w just my WB. Don't need a scan tool. So the stumble is a consequence of the engine control transitioning from O/L to C/L. There are delays built into the calibration which accommodate the stock setup. Change the cams and things move faster becoming somewhat less stable. So the calibration needs to be modified in order to control the motor more tightly in order to control the instability. In doing the tuning I change parameters in order to keep a tighter leash on the motor reaction to inputs. The stock values tend to exaggerate the inputs to a modded motor.
As I have explained at other times, part throttle tuning is more important than WOT. In fact, WOT DEPENDS on how good part throttle is. Partly because we spend so much more time at part throttle than WOT. PT is time and fuel consuming which is why it isn't very commonly done.

This is an interesting and plausible hypothesis . If it is root cause then you should be able to insert a stock chip and replicate the hesitation at the onset of closed loop for the OP at about 125deg.

If not then modding the code to fix a hardware issue may ensue. It is what we used to call "dog chasing tail" of "F-ing the dog". I've seen this happen on this forum before. To keep that from happening ultimately we'd use in incircuit emulator and watch what the code did (equivalent of data logger). Rather that look at our code and say "it can't do that" we'd see what it did then look at the code to see how it was happening. Not the other way around.

I will be watching this thread closely for the actual resolution to the OP's issue. It's not your everyday run of the mill ZR-1 issue

[XfireZ51]

Well just came back after loading new bin and startup. It worked. Got passed the 47.75C point and no stumble. Viewing the WB, I could see it stayed in O/L then got in to C/L at about 68C. It went a bit lean momentarily but then stabilized. Overall, warmup went pretty smoothly. Granted its 85F in the garage but that allowed it to warm up faster. I've attached a screenshot of TPRT w the parameters I changed. You can see the stock values as well.
So IIUC, as we see in the screenshot, the threshold for Hot/Cold MAT is set at 4.25C. Above that point, ECM did use 47.75C and now its 57C for the C/L timer, which at cold CTS, will be 50sec. I didn't include one other parameter which is the CTS Threshold for Hot/Cold or 70/29C. Anywhere in between is considered Warm.
I'm assuming that the timer doesn't change once its tripped. IOW, if it starts at Cold that's the timer, it does not change as it transitions from cold to warm for example.

[LGAFF]

For my car, extreme heat the problem is almost unnoticable.....very cold weather is when the car really stumbles

*Bought items to make a new o2 extension....

I have already tried other chips/ECM....problem stays

[XfireZ51]

Originally Posted by LGAFF

For my car, extreme heat the problem is almost unnoticable.....very cold weather is when the car really stumbles

*Bought items to make a new o2 extension....

I have already tried other chips/ECM....problem stays

Ok. Knock yourself out.