Interesting. I'll add that to what I'm logging and see if I have the same result.
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Interesting. I'll add that to what I'm logging and see if I have the same result.
Is that an E38 still? My IVT and Inj Tip Temp show they have the exact same effect on the rich fueling after flash... that's why I just refer to IVT.
Attachment 57346
Attachment 57347
I don't think it pertains to any one parameter. "I think" it has to do with any of the calculated temps that have to be back calculated after reflashing. This is why, if I remember correctly, GM even says to drive it for 15 minutes after programming for correction verification...
If you are asking if my ZL1 has a E38 then no. E67. The reason I say there is no definitive correlation to IVT is I could not match the pattern of behavior. Here is IVT from the same log.
http://www.hptuners.com/forum/attach...id=57354&stc=1
I was flashing and just idle logging today and looking for this issue. One interesting thing I saw & heard was after I flashed each time....ST fuel trims would go negative 25 quickly and then the LT trims would follow. As soon as the LT trims hit somewhere around -15 I'd hear some audible clicking coming from somewhere (sounded like back by the fuel pump but unsure). About 5ish audible clicks in rapid succession. As soon as these clicks happened, I could see my ST and LT fuel trims reset to zero and start fresh again.
This would go through about 3 cycles:
-- LT trims hit -15....get the clicks and the trims reset (2-5 min range)
-- LT trims hit -10....get the clicks again and trims reset again (another 5ish min)
-- Then the LT trims permanently settle in around -4. No more clicks, and it seems stable.
This was repeatable after every flash.
Was kind of interesting. Perhaps everyone knows about this already and it has nothing to do with this issue. But I found that once the fuel trims reset twice....it seems the trims stabilize.
I was driving with cruise control on down the freeway. It did not skew the injector temps, but I could be all wet.
Okay so not arguing ( maybe a little LOL ), but this follows exactly with injector temps. I took a cold (38 deg F) 2012 ZL1 and flashed it. Started and let it idle for 20 min. Injector temp reached 120F and I shut it off. At he time it was -1.6 in FT. Re-Flashed it with the exact same tune. Started the car and Injector temps were 185+ and FT went to -26. Let it idle for 20 min. As the injector temp went down so did the FT. IVT however varied throughout. I will post the log if you really need to see it.
http://www.hptuners.com/forum/attach...id=57435&stc=1
IVT should have started from around coolant temp and warmed up over that same 20mins after the warm flash... If it does (the E38 does) then not sure how IVT LTFT error could not follow the same as the Inj Tip Temp unless thre's a problem with the scanner or the calc, since the %error is tracking against temp is all... so you would be saying the IVT is not warming up, or your saying it's actually jumping around? Or, the %Error is not the same %Error used for Inj Tip Temp.
Post the same chart for the IVT vs. LTFT Error, or just post the log. I wanna just see if IVT temp increases like it does on the E38.
Sometimes the chart will pick up some erroneous data like low IVT temp at the start or end of log, making it look inconsistent.
I'll try to do the same test over the weekend. I have an E38 and E40 here now I can try it on, just to see if I get the same results
I would think IVT should go from ECT up to whatever it goes up to over the relatively same period of time though. But maybe not, who knows. These things are weird.
I have found cruise control to really mess with the AFR (found it in open loop, went rich like .8/.9) ....this is on a dyno/roller when heating up eng/diff. Never tried it on the the street.
Also, if you tune the E38 in open loop, the rich after flash phenomenon is practically non-existent.
Ed M
Here is the log. You will se the IVT does go up but settles and then jumps around a little. All the time the injector temp falls and FT drops.
I see what you mean.. the decrease in Inj tip temp is a fair bit smoother than the increase in IVT. I'm surprised to see IVT get to 300* and stabilize in under 2 minutes on yours. Mine always seems to take a lot longer than that
Inj tip takes closer to 20 minutes to stop dropping, around 133*F
I assume injector temp starts at coolant temp and goes towards IAT (or manifold temp)
And IVT starts at ECT and increases from there based on engine load, commanded lambda, etc.
I would say the E67 does not have this problem, since I see your LTFT go to -25% right after startup, but 1min 33 seconds in it goes right from -25% to -4.7 in 25 seconds and stays there. What are you graphing? Im graphing Long Term FUel Trim (Sensor) vs IVT and ITT, but you can easily see the LTFT values in the Channels jump from -25% to -0.8% instantly, then in the next 25s it ramps from -0.8% to -4.7%. All this happens between 1m 33s and 1m 59s.
Also, the reason the IVT starts jumping around is because you started revving the engine....
Attachment 57450
EDIT: I changed LTFT to STFT and now I see what your talking about kinda... your IVT temps start high and ramp up very fast, the trend is still there for them too, but the inconsistent data with IVT is created from the revving. So I wonder why there's a difference in the IVT calc between these engines, mainly the E38 and E67.
What is being graphed is total fuel trim (short and long) not just long term. So at 2 min. total trim is -26 with short terms maxed out. At 4 min it is -24 at 10 min it is -12 and by 20 min it is down to -1 to -2. certainly you would not argue that only long term fuel trims contribute to the total fuel trim. As for the IVT it os 306 at 5 min. 299 at 10 min. and 306 at 20 min. All the time the total fuel trim is going down the IVT is not really changing.
Just 30 seconds prior to this total fuel trim is only -1.6. Reflash and a total of -26. No reflash and the car starts and maybe it is -2 to -3 every time with it settling to -1.6 very quickly.
Here is the car being flashed COLD and started.
http://www.hptuners.com/forum/attach...id=57453&stc=1
Interesting.
I do not remember this issue with EFI Live. I own it as well and will test. According to my logs. Every time I flash the car the injector temp starts at whatever the ECT was and then is calculated from there. Hence "HOTFLASH" issue. I am going to test EFI Live this weekend to validate.