Off throttle tuning LTFT
Off throttle tuning LTFT When I Autotap my buddies car when he let's off his car goes to 25% lean on the LTFT. He has heads/cam and they drilled a hole in the throttle plate to have the car idle. What can I do to fix the fact his car is so lean off throttle. It isn't that bad otherwise.
On The Tree
Joined: Jan 2003
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From: Central MD
Re: Off throttle tuning LTFT Not enough info to help. Did you set a code (you should have)? What are the cruising (1500rpm)LTFT's? What does the MAF read? Are there any other DTC's? What rpm is his idle and what cam? Who did his tuning/or is this not done yet?
Do you mean STFT's are jumping that high? Off throttle (decelerating) is not a big deal. LTFT's are best checked cruising at a steady rpm and speed.
Do you mean STFT's are jumping that high? Off throttle (decelerating) is not a big deal. LTFT's are best checked cruising at a steady rpm and speed.
Re: Off throttle tuning LTFT Every once in awhile he will set a code but not all the time.
Personally I think he is lean off throttle because the hole might be drilled to large and it's letting air in even when the throttle is shut.
My main question is there anything I can do to richen up the car with no throttle just at idle or when letting off in a shift. In ls1 edit is there a table to change this if so what?
Thanks
Personally I think he is lean off throttle because the hole might be drilled to large and it's letting air in even when the throttle is shut.
My main question is there anything I can do to richen up the car with no throttle just at idle or when letting off in a shift. In ls1 edit is there a table to change this if so what?
Thanks
TECH Addict
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Re: Off throttle tuning LTFT Wicked C5 -is it a Vette (fly by wire) or an F- body? Seems that most Vettes don't need a tb hole drilled. I think the pcm will adjust the pintle in the TB as it "learns". Just a thought for whatever it's worth.Good Luck. <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
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Re: Off throttle tuning LTFT I have ls1 edit for him and yes the Vette is fly by wire.
What basicly I am trying to see if I can tune out the off throttle leaness with ls1 edit or if he needs to get a new throttle body.
What basicly I am trying to see if I can tune out the off throttle leaness with ls1 edit or if he needs to get a new throttle body.
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Verdad Gallardo TECH Addict
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Re: Off throttle tuning LTFT <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" /> Can't wait to get my Iforged <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" /> <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />
10 Second Club
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From: Cloud Nine
Re: Off throttle tuning LTFT Why stress out the mixture being leaner than Stioch on a closed trailing throttle ????
It should be for economy and emissions sake , IAC will fully open to bypass extra air around the TB as part of the std strategy , injectors are also shut off on deaccel to save fuel
It should be for economy and emissions sake , IAC will fully open to bypass extra air around the TB as part of the std strategy , injectors are also shut off on deaccel to save fuel
Re: Off throttle tuning LTFT Try checking these.
What are the IAC's. If they are 0, then the throttle body hole might be WAAAY to big.
Another gimme, when the LTerms peg at 25% off the throttle is the PCV system. Make sure that the PCV system and all other intake intrusions (stuff that plugs into the intake after the throttle body) are plugged in correctly.
What kind of exhaust does he have? A short ended exhaust and a big cam will induce a reversion of fresh air into the exhaust up to a point. If the exhaust is short enough, it will actually suck fresh air right up to the O2 sensors setting off 25% LTerms.
Good Luck,
Kevin
What are the IAC's. If they are 0, then the throttle body hole might be WAAAY to big.
Another gimme, when the LTerms peg at 25% off the throttle is the PCV system. Make sure that the PCV system and all other intake intrusions (stuff that plugs into the intake after the throttle body) are plugged in correctly.
What kind of exhaust does he have? A short ended exhaust and a big cam will induce a reversion of fresh air into the exhaust up to a point. If the exhaust is short enough, it will actually suck fresh air right up to the O2 sensors setting off 25% LTerms.
Good Luck,
Kevin
Re: Off throttle tuning LTFT </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by NoGo:
<strong> Try checking these.
What are the IAC's. If they are 0, then the throttle body hole might be WAAAY to big.
Another gimme, when the LTerms peg at 25% off the throttle is the PCV system. Make sure that the PCV system and all other intake intrusions (stuff that plugs into the intake after the throttle body) are plugged in correctly.
What kind of exhaust does he have? A short ended exhaust and a big cam will induce a reversion of fresh air into the exhaust up to a point. If the exhaust is short enough, it will actually suck fresh air right up to the O2 sensors setting off 25% LTerms.
Good Luck,
Kevin </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The car has a 230 cam ported heads long tube headers cats and Borla stingers
Personally I am thinking the hole is to big we may try another t/B and go from there
<strong> Try checking these.
What are the IAC's. If they are 0, then the throttle body hole might be WAAAY to big.
Another gimme, when the LTerms peg at 25% off the throttle is the PCV system. Make sure that the PCV system and all other intake intrusions (stuff that plugs into the intake after the throttle body) are plugged in correctly.
What kind of exhaust does he have? A short ended exhaust and a big cam will induce a reversion of fresh air into the exhaust up to a point. If the exhaust is short enough, it will actually suck fresh air right up to the O2 sensors setting off 25% LTerms.
Good Luck,
Kevin </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">The car has a 230 cam ported heads long tube headers cats and Borla stingers
Personally I am thinking the hole is to big we may try another t/B and go from there
Re: Off throttle tuning LTFT I am worried with it setup like that it will produce codes. Also from what I have found it is better to have to computer closer to 0 on the LTFT even off throttle. The car won't have to take the time compensating and you'll get a more instant throttle response