alright guys. So I have a 2005 Silverado with 8.1L bone stock except for the STS turbo kit installed on it. Converted it to speed density and trying to get the tune right. There are a few issues I can't quite figure out so that's why I'm here to see what you guys might have to say. I have 3 issue I'm trying to resolve.
#1 So how do I get any kind of MAF reading with a SD tune? I really want to use MAF readings for a VE calculator program but I can't even look at any MAF reading in SD format? Doesn't even give me the option to graph it? just blank.
#2 While building my idle tune I have noticed that once ECT gets to about 150degF I get surging all the way up till operating temp... and in Park sometimes even at operating temp. watching my data list... and knowing I have closed loop turned off and FT's turned off. During the surging I can watch the O2's and wideband go to about 17:1 it seams as though PCM corrects for lean condition and the electronic throttle compensates for the RPM drop. Then it revs up then down then up then down (about 100RPM variation) then smoothes out. Runs for a while just fine then repeats. I have multiple datalogs showing this and I have no clue why. Timing table is smooth at that point. and no big change in VE table there so it can't be an interpolation issue.
#3 This problem is really ticking me off. Especially since the RRT doesn't work on this PCM. Every time I burn the PROM it will not start. Well.... it starts.. runs for 3 seconds... but then dies. Only thing I can do to fix it is go into the scanner controls and command AFR to 8:1-9:1 and then it will start... almost die...catch... rev up....slowly come down in RPM start to load up and then I turn off the AFR command and its fine. every time after that I start it then it starts up just fine until I reflash the PROM again.
I included my scanner config, my tune, and two datlogs of my most recent work for all those that would like to check out everything. Feel free to yell at me for everything I'm doing wrong or offer advice in any area as I have spent entirely too much time with this so far with very slow progress as I am learning how to use HpTuners on this truck.
It looks like your approach is setting the ignition timing to a set 16deg then let fuel trims tune the VE table in the idle range? I like that idea. Makes good sense. Which brings me to a particular scenario I remember dealing with. And it has been frustrating because it seams like I'm chasing my tail. I let vehicle warm up to operating temp. Then look at the VE error table and adjust accordingly. But then when I test drive It, it seams at though it is messing up the averaging for the VE error table. I did go into the DFCO and disabled deceleration fuel cutoff to help with this but sure didn't seam to fix it.
One question before I go datalog.... How do the VE error table and fuel trim values compare? or do they? My theory was to build my VE table in open loop first with the VE error. But that doesn't seam to be getting me anywhere with the idle.
My guess would be your have an error in logging your wideband, they should match pretty close. I also made a changes for your starting after flash. When in sd mode you must have a maf code set, after a flash codes are cleared. So first start after a flash is always rough, but it should stay running now.
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