MAFless tuning?
09-21-2005, 10:43 AM
#1
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MAFless tuning? I understand the advantages to MAFless tuning; but my question is are people leaving ther MAF sensors disconnected after the tune?
09-21-2005, 11:15 AM
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no you dont HAVE to but it does a few things most importantly
1. gets rid of the secodnary table
2. Re-enables the functionality of the HO and LO tables
Or you could flash your PCM to a 01+ OS and get 1 by default and 2 you will have to copy your HO table to your LO table.
I have been running like this for a year and some change now
1. gets rid of the secodnary table
2. Re-enables the functionality of the HO and LO tables
Or you could flash your PCM to a 01+ OS and get 1 by default and 2 you will have to copy your HO table to your LO table.
I have been running like this for a year and some change now
09-21-2005, 11:17 AM
#5
Negative...you'll just have to live with running only one octane table (as in, copy the high octane table to the low octane, and leave it that way). You'll still have KR, though, so no worries about that. You just won't give your car any room to "learn" if it gets some bad gas.
09-21-2005, 11:23 AM
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ok, so I dont need to purchase the 1 bar to be able to run a speed-density system, but if I DO purchase the 1 bar will I still be able to tune with a MAF? I ask because a friend and I are splitting the cost of the software and I want to tune SD, and he wants to tune with a MAF.
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09-21-2005, 12:05 PM
#12
So if you have a 98 and you tune mafless you will always be running off the "secondary" ve table right? If so, how accurate is this for a daily driver and, ran like this, how does the PCM make fueling changes for drastic temperature changes like winter/summer etc??? Does the IAT sensor still affect fuel delivery? Are the front O2s even used at all? Pardon my ignorance as I am very new to mafless tuning. 
09-21-2005, 12:09 PM
#13
Originally Posted by SSblack98
So if you have a 98 and you tune mafless you will always be running off the "secondary" ve table right? If so, how accurate is this for a daily driver and, ran like this, how does the PCM make fueling changes for drastic temperature changes like winter/summer etc??? Does the IAT sensor still affect fuel delivery? Are the front O2s even used at all? Pardon my ignorance as I am very new to mafless tuning.
1. Open Loop
2. Closed Loop
In closed loop, the PCM uses the stock, narrow band O2 sensors for feedback to adjust the fueling. Your IAT still works, everything still works. You just aren't getting an airflow reading from the MAF sensor. Instead, you are basically telling the PCM just how much air you are getting, and putting it in a format it can understand (the VE table).
The computer just uses a bunch of "look up" tables to determine the airflow...essentially, what you are doing is getting rid of one of those tables.
09-21-2005, 12:42 PM
#14
Like I said I am very new to this so I didn't know the PCm can run in closed loop with the MAF unhooked. My tuner has unhooked the MAF and tuned the ve table to about 14.7 afr with a wideband. But this was done at 80 degree ambient temps so will I need to retune when the ambient temps are 30 degrees this winter? I was under the impression that I was now running in open loop all the time witht he maf unplugged. Thanks for the input by the way!
09-21-2005, 12:54 PM
#15
As long as your tuner put you back in closed loop you are running closed loop 
You *shouldn't* need a retune for the winter since you still have your IAT sensor...that's all a part of the airflow calculations. I don't know for sure, though, since I've only been running full time SD since early this summer.
You *shouldn't* need a retune for the winter since you still have your IAT sensor...that's all a part of the airflow calculations. I don't know for sure, though, since I've only been running full time SD since early this summer.
09-21-2005, 01:03 PM
#16
Originally Posted by SSblack98
But this was done at 80 degree ambient temps so will I need to retune when the ambient temps are 30 degrees this winter?
as part of the normal calculations, the ambiant tempature of the air is taken into account.
matter of fact, it can go as far as take the measured ambiant air intake temp, and the current engine temp, and correct for the warm engine intake manifold heating the incoming air.
overkill?? in my opinion yes... but its accurate.. lol.
09-21-2005, 01:37 PM
#17
Ok, so how do I know if my tuner has me back in closed loop or not? Also, I have pretty bad surging below 2k while driving. I was told I could increase timing at low rpms and help this. What do you all think of that and what would be the best way to go about doing it? Thanks again for all the info...
09-21-2005, 03:02 PM
#19
My car actually idles very well considering the decent sized cam. TSP did a pretty good job on the original tune with that. It only surges for a little bit when started up cold then smoothes out. But it surges pretty bad while driving at low rpms. It is better or worse at times which I find strange also. Does surging indicate too rich or too lean in the ve table?
09-21-2005, 07:02 PM
#20
Originally Posted by SSblack98
Ok, so how do I know if my tuner has me back in closed loop or not? Also, I have pretty bad surging below 2k while driving. I was told I could increase timing at low rpms and help this. What do you all think of that and what would be the best way to go about doing it? Thanks again for all the info...
I can put the car back in closed loop speed density very easy. 