Newbie tuning the T-Rex, few questions, can someone look at last couple files quick?
04-09-2005, 07:17 PM
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Newbie tuning the T-Rex, few questions, can someone look at last couple files quick? Hey guys, I read all the stickies in here and the HP Tuners site. For some background, I have HP Tuners V1.6, T-Rex, LS6 intake, most of the bolt-ons, specifics can be seen on my homepage in the sig. I've been following the SD LTFT tuning method. So far I've flashed the ecm 6 times. Before the latest flash, I took the car out for an 82 min cruise. Since then, I have logged 2 more 20 min drives on that current tune.
My questions are:
1. a. It seems like my LTFT's always start rich then work their way lower and/or negative. Is this normal? Is this due to the engine and engine bay being cooler at startup or what?
b. When logging the LTFT's, do you need to log from the point of resetting the fuel trims? Or can you take the car out a few times, say 20 mins each without logging to let the LTFT's learn, then come back another time and take it on a 20 mins cruise while logging? I guess I'm trying to say is, will LTFT's be different if logging from the point of resetting them vs. logging them after shutting the car down a few times? If so, when should you start logging?
2. What cells in the VE table should the car idle at? Mine seems to be up near 70-75 kPA in the 800-1200 cells. Is this normal? This is with the MAF unplugged for the LTFT tuning and an idle of about 1000 rpm.
3. When tuning the idle, does the MAF need to be plugged in or should it be unplugged an in SD mode? I have gotten 0 counts for IAC with the MAF unplugged. Is the IAC dependant on the MAF? If I plug the MAF back in, will I get IAC counts? I had a decent idle with the MAF, then when I unplugged it, the car wouldn't stay running, so I had to play with it to idle without the MAF.
4. In different write-ups, I've seen to take the ave. LTFT's and straight up add them to the VE table in those cells, I've seen to take the ave. LTFT's and add the ave. STFT's and take that number and change the VE cells, and I've seen to take 1/2 of both things I just listed above and change VE cells by that amount. Which way works best?
Sorry if this is newbie and rehashed stuff, but I haven't found the answers from searching this site or HP Tuners yet.
Also, would anyone care to look at my last few files to make sure I'm on the right track and offer any suggestions?
My questions are:
1. a. It seems like my LTFT's always start rich then work their way lower and/or negative. Is this normal? Is this due to the engine and engine bay being cooler at startup or what?
b. When logging the LTFT's, do you need to log from the point of resetting the fuel trims? Or can you take the car out a few times, say 20 mins each without logging to let the LTFT's learn, then come back another time and take it on a 20 mins cruise while logging? I guess I'm trying to say is, will LTFT's be different if logging from the point of resetting them vs. logging them after shutting the car down a few times? If so, when should you start logging?
2. What cells in the VE table should the car idle at? Mine seems to be up near 70-75 kPA in the 800-1200 cells. Is this normal? This is with the MAF unplugged for the LTFT tuning and an idle of about 1000 rpm.
3. When tuning the idle, does the MAF need to be plugged in or should it be unplugged an in SD mode? I have gotten 0 counts for IAC with the MAF unplugged. Is the IAC dependant on the MAF? If I plug the MAF back in, will I get IAC counts? I had a decent idle with the MAF, then when I unplugged it, the car wouldn't stay running, so I had to play with it to idle without the MAF.
4. In different write-ups, I've seen to take the ave. LTFT's and straight up add them to the VE table in those cells, I've seen to take the ave. LTFT's and add the ave. STFT's and take that number and change the VE cells, and I've seen to take 1/2 of both things I just listed above and change VE cells by that amount. Which way works best?
Sorry if this is newbie and rehashed stuff, but I haven't found the answers from searching this site or HP Tuners yet.
Also, would anyone care to look at my last few files to make sure I'm on the right track and offer any suggestions?
Last edited by BuckeyeROC; 04-09-2005 at 07:32 PM.
04-16-2005, 11:17 PM
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King of Pigskin Knowledge
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Anyone have any answers to the above?
Also, I have some new files. Can someone please look and make sure nothing is out of the ordinary and that I am on the right track? I'm thinking of just fine tuning some more LTFT's, then trying to scale the MAF to match next. If you can check out my log and bin, let me know, it would be a huge help. Thanks.
Also, I have some new files. Can someone please look and make sure nothing is out of the ordinary and that I am on the right track? I'm thinking of just fine tuning some more LTFT's, then trying to scale the MAF to match next. If you can check out my log and bin, let me know, it would be a huge help. Thanks.
04-18-2005, 10:07 AM
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my advice would be, to ignore those GD LTFT, and get yourself on a wideband. I have perfect a/f, and my fuel trims are all over the place at idle. i wasn't properly able to tune until i got on a wideband. When i give it wide open throttle, the LTFT get better, but they are still crazy. i dont know if i answered any of your questions but, the tune we made showed 431rwhp on the dyno, pretty nice for just a cam!(Trex)
