Cannot seem to run without MAF for tuning VE
05-09-2005, 03:25 PM
#41
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When I set the MAF fail freq to 0, it seemed to drive fine, but I didnt take it far since I didnt want to risk it dying on the street and having to reflash it on the street. So I just disconnected the MAF instead.
HumpinSS, so I assume that I can do it by just looking at my LTFTs (the way I have been doing it) and just adjust my VE table accordingly. Im slightly lost on what Phil99Vette says, I mean you are right in that the LTFTs/STFTs are not going to remain 0 even after you reset it in closed look. In open loop it definetely will remain 0, but not closed, The second I hit reset, you will start noticing it learning/trimming fuel again.
One more thing, so the LTFT/STFT histrogram in HPtuners is actually in percent? I thought it was actual values from what I saw in the HPtuners forum about how you take the LTFT and add the STFT and then multiple by .5 and you use that to adjust the VE cell. If its percentage than I need to use a different calculation for sure on my VE spreadsheet I created.
Dixit
HumpinSS, so I assume that I can do it by just looking at my LTFTs (the way I have been doing it) and just adjust my VE table accordingly. Im slightly lost on what Phil99Vette says, I mean you are right in that the LTFTs/STFTs are not going to remain 0 even after you reset it in closed look. In open loop it definetely will remain 0, but not closed, The second I hit reset, you will start noticing it learning/trimming fuel again.
One more thing, so the LTFT/STFT histrogram in HPtuners is actually in percent? I thought it was actual values from what I saw in the HPtuners forum about how you take the LTFT and add the STFT and then multiple by .5 and you use that to adjust the VE cell. If its percentage than I need to use a different calculation for sure on my VE spreadsheet I created.
Dixit
05-09-2005, 03:27 PM
#42
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Originally Posted by 405HP_Z06
For a Corvette, Do NOT unplug the MAF sensor to disable it for SD tuning. Set the MAF fail frequency to 0. The MAF sensor also contains the IAT sensor. If you unplug it the PCM won't function correctly in SD mode because of the lack of IAT data.
You will get a code P0103 when you do this. Some turn off the code, but I prefer to leave it on to verify that I am in SD mode and the MAF sensor has 'failed'.
You will get a code P0103 when you do this. Some turn off the code, but I prefer to leave it on to verify that I am in SD mode and the MAF sensor has 'failed'.
Dixit
05-09-2005, 03:29 PM
#43
Originally Posted by Phil99vette
I am not trying to be a smart *** but you CAN NOT tune the VE table accurately with the LTFT and STFT adjusting fuel. I have tuned 2 corvette's and you just can't plain do it. You lower your VE table and reflash, LTFT is +20, when you reset fuel trim your car is gonna be soo outta wack. You need to pull the MAF, tune the ve table, and than retune your MAF.
If your tune is close enough you don't need an idle relearn.
Phil
If your tune is close enough you don't need an idle relearn.
Phil
05-09-2005, 04:19 PM
#44
Originally Posted by Dixit
Well thats news to me. Hahahaa Learn something new. Will change it by putting fail freq to 0. But I have to see it flash REDUCED ENGINE power on the DIC to ensure im in there right? I mean when I did the fail freq of 0 and drove about 100-200ft nothing cam on, it idled fine for about 2mins too, still no REDUCED ENGINE power message. I know sometimes it takes longer, Guess I will try that on my subdivision instead of doing that on the drive home. Last thing I want to do is have the car die and then hold up traffic while I reflash the VCM.
Dixit
Dixit
The ONLY code you should see if you set the MAF sensor fail freq to 0 is the P0103!
Last edited by 405HP_Z06; 05-09-2005 at 05:34 PM.
05-09-2005, 04:35 PM
#45
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I forgot about the vettes having a different maf sensor than the F-body 
. What he said fail it and when it sets the code dont edit it out just to remind you that you are running SD
. What he said fail it and when it sets the code dont edit it out just to remind you that you are running SD
05-09-2005, 04:52 PM
#46
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405HP_Z06, you are the man. Thats all I needed to know. So all this time I was in SD mode and it was working, but we (C5 owners) are not supposed to do the unplug MAF.
We need to update that in the stickies cause like I said before, most of the HOWTOs and READMEs are based on Cameros, Fbodys, Transams, other LS1 cars/trucks.
Damn this is good info. Guess I will just set it to 0 now before the drive home and log the crap and then start my adjustments.
Dixit
We need to update that in the stickies cause like I said before, most of the HOWTOs and READMEs are based on Cameros, Fbodys, Transams, other LS1 cars/trucks.
Damn this is good info. Guess I will just set it to 0 now before the drive home and log the crap and then start my adjustments.
Dixit
05-09-2005, 05:22 PM
#47
Originally Posted by Dixit
405HP_Z06, you are the man. Thats all I needed to know. So all this time I was in SD mode and it was working, but we (C5 owners) are not supposed to do the unplug MAF.
We need to update that in the stickies cause like I said before, most of the HOWTOs and READMEs are based on Cameros, Fbodys, Transams, other LS1 cars/trucks.
Damn this is good info. Guess I will just set it to 0 now before the drive home and log the crap and then start my adjustments.
Dixit
We need to update that in the stickies cause like I said before, most of the HOWTOs and READMEs are based on Cameros, Fbodys, Transams, other LS1 cars/trucks.
Damn this is good info. Guess I will just set it to 0 now before the drive home and log the crap and then start my adjustments.
Dixit
Good luck and let us know how it works out.
