How exactly does IAT Temps affect the PCM
Thread Starter
Teching In
Joined: Sep 2002
Posts: 38
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From: Jensen Beach, FL
How exactly does IAT Temps affect the PCM I know you can zero out the KR values inthe IAT table..But....I know the PCM still uses the temp info somehow... For example..Disconnct the IAT and the temp measures -something below 0...And dumps a ton of fuel...
In searching the editable tables in LS1-Edit I can't find a single place that contols this...
Does it change the LTFT's? Does it try to make it richer if it sees colder temps?if this is the case then the timing tricker (4.7k ohm resistor) Only tells the PCM to add more fuel.. If it's too much then the LTFT's will go more negative..Is this the goal? <img border="0" alt="[Banging Head]" title="" src="graemlins/gr_banghead.gif" />
In searching the editable tables in LS1-Edit I can't find a single place that contols this...
Does it change the LTFT's? Does it try to make it richer if it sees colder temps?if this is the case then the timing tricker (4.7k ohm resistor) Only tells the PCM to add more fuel.. If it's too much then the LTFT's will go more negative..Is this the goal? <img border="0" alt="[Banging Head]" title="" src="graemlins/gr_banghead.gif" />
Thread Starter
Teching In
Joined: Sep 2002
Posts: 38
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From: Jensen Beach, FL
Re: How exactly does IAT Temps affect the PCM </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Nic00Z28M6:
<strong>PE vs Temp, there lies part of your answer.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I believe that is Coolant Temps only. But thanks for that info.. I think this also helps...
<strong>PE vs Temp, there lies part of your answer.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I believe that is Coolant Temps only. But thanks for that info.. I think this also helps...
TECH Apprentice
Joined: Jan 2002
Posts: 384
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From: Murphy, TX
Re: How exactly does IAT Temps affect the PCM Have you been following Kevin P's thread on the mailing list?
Once upon a time I was told that the base fuel equations were just that. (Cheaper to compute than store.) The implication is that there may not be much in the data segment that would give a hint as to how the IAT would influence fueling. Some might claim that air temp is already factored into the design of the MAF sensor. If you really want to figure it out you'll need an adjustable resistance on the IAT circuit and mucho patience.
Once upon a time I was told that the base fuel equations were just that. (Cheaper to compute than store.) The implication is that there may not be much in the data segment that would give a hint as to how the IAT would influence fueling. Some might claim that air temp is already factored into the design of the MAF sensor. If you really want to figure it out you'll need an adjustable resistance on the IAT circuit and mucho patience.
