Funny how that is... I thought there was an outside chance that the tunes were a somewhat generic binary file that either software package could recognize.
Funny how that is... I thought there was an outside chance that the tunes were a somewhat generic binary file that either software package could recognize.
You can enclose it in a zip file.Originally Posted by Ben.
Yes, I can decipher it, I'm analyzing it.
Bit the bullet and put a wideband on it. set my entire EQ ratio map to 1, and power enrich to 1.15 so that I can just target a global A:F of 12.8ish.
VE map is pretty good, made a couple of small touch ups, but nothing significant. One thing I have noticed is that it goes slightly lean as it's returning to idle, around 14.2:1, it's at this point that it shoots back up and gets itself in line before settling at idle with a 12.8A:F ratio. Normal idle is around 40-45kpa, but it was going lean with slightly more vacuum, down to 30-35ish kpa.
So as a test procedure, I used real time tuning to smash 20% more fuel in at low vacuum up to 1200rpm, and the thing was perfect! Gave it a few revs, stayed at 12.8 from any RPM down to 1100 where it would now catch, then slowly return down to idle (it's catching high due to a raised Base RAF and my slow returning IAC, as shown in the log above) Brilliant, I'll just add more fuel into it there and be done with it. Made the same changes to my VE, flashed the tune, no deal. Does the same thing as before. Went back into real time tuning to ad more in, same deal, doesn't matter what I do I can't get it to stay rich on return to idle, don't know why it worked the first time, but that's the problem at this point. Monitoring my injector pulsewidth it's normally around 1.3-1.4ms at idle, it now shows 1.5ms the whole time rpm is falling back to idle, even when it goes lean.
So, in short, what can I do to keep it a bit rich on return to idle?
If DFCO is enabled, disable it and try.
Does HPT do compare of current tune to previous tune, if so can you show some screenshots of what you did...
it does, but I've probably gone through 30 odd tunes today, most of which I've now deleted.
I thought I'd go back to basics. I 0'd out my idle overspeed and underspeed tables, started the car and went about finding a good stable idle, problem is, I can't get it to idle steadily no matter what I do. I will use bi-directional controls to lock the IAC at about 30 steps, lock timing to 15 degrees (tried more and less also), but still no luck. I've taken away every possibly variable, fixed air delivery, fixed timing, and just slightly correcting fueling, but it just gets into an oscillation of 600-1200rpm. during this the wideband is pretty steady at 12.5-13, doesn't move around a great deal, however I think this might be due to placement.
I remember trying a similar thing a year or so ago when I first got HPT, with the same result. At the time I asked a fairly well respected tuner and his response was "yeah, that's just what they do", but I can't help but think I should be able to get it perfectly stable with the above scenario. So I'd concluded that my VE map is the issue, or my injector data was no good, tried referncing some other tunes for data but haven't had a good chance to try it yet.
From your experience with LS1 PCM's in particular, is there any reason it SHOULDN'T idle stable with the IAC and timing locked to reasonable numbers?
Nope, no reason.
So, decided I couldn't possibly be this bad at tuning. Started pointing at things in the engine bay and swearing at them, pulling it apart and finding something to blame. Sure enough, there was a few days of removing and unnecessarily refitting my intake 4 times. Long story short, injector flow was all over the shop, injector seals were cactus, intake manifold gaskets had seen better days and in the process of me displaying my masculine strength to those around me by severely over tightening my intake, cracked it in several places.
The vac leaks were so bad that I decided vac leaks couldn't be a problem in the first place because I physically couldn't physically spray enough carby cleaner around the intake to seal it. I specifically remember having one can in each hand and absolutely flooding up and down each side of the intake and it making no difference, so clearly vacuum leaks weren't the problem
Anywho, I've now got it 99% right after undoing all the things I did to get it to run the way it was before. Closed loop, 700rpm idle, and if I lock the IAC and timing I can bring it down and have a stable idle at 700rpm with nothing funny going on. The only issue I'm battling now is, still, an oscillation on return to idle. HOWEVER, it's only when running closed loop, if I set it to open loop, even with my VE map dialled in around 14.5:1, it runs perfectly inline with what my IAC is doing, catching high then slowly coming down.
Is there any way to get it to ignore O2 feedback on overun? I've tried stabbing a bit of extra fuel into my VE map on its return path to idle, which helped slightly, I'm worried about putting to much in, and having the ECM trying to pull to much fuel as it gets into my actual idle zone. Any thoughts?
good job
reinforces that physical issues can't be tuned around, and that some issues are not always easily apparent.
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