Idle tuning

[mrr23]

is the LTIT in the negative? if so, force it back to zero and see how it reacts.
how i forced my LTIT back to zero is i went into the scanner, while the engine is running, and lowered the timing with the VCM Controls. this forces the PCM to increase the IAC and add more airflow. i let it idle like this for about 2 minutes. once the LTIT got back to about zero, i shut the timing minus off.

another way i've read is some take the positive and negative battery cables, off the battery, and touch them together. this takes out the stored energy in the PCM and resets everything.

[Abdullah]

sorry for the newbe question but what is RAF?

[WS6FirebirdTA00]

Idle airflow

[Alvin]

is the LTIT in the negative? if so, force it back to zero and see how it reacts.
how i forced my LTIT back to zero is i went into the scanner, while the engine is running, and lowered the timing with the VCM Controls. this forces the PCM to increase the IAC and add more airflow. i let it idle like this for about 2 minutes. once the LTIT got back to about zero, i shut the timing minus off.

another way i've read is some take the positive and negative battery cables, off the battery, and touch them together. this takes out the stored energy in the PCM and resets everything.

One little tip you can do is to force max negative LTIT to 0. This is the way I've been doing them for a few years now. the idea is that you want to error on the side of caution just like shooting for a fuel trim of -5 is sometimes a better idea than 0. The big problem with LTIT is the car has to pretty much fully warm up to update itself. Having a car that has a slightly high rolling and settling idle is an annoyance.. having a car that dies when you lift off the gas is a big time problem and huge annoyance.

[killerjuice]

subscribed! good info in here guys, I will walk through this tomorrow, sounds like my issue is fueling.

[Abdullah]

The reason that I asked this is that I created a STIT+LTIT PID in order to correctly setup RAF. No matter what, it always reads a negative value. I mean I can get it down into the 6's and the car is barely running and it still wants me to pull air. I was thinking the maybe the MAF had something to do with getting the values correct and since I dont have one, hence the erroneous data.

Any suggestions? Another way perhaps?

i would say from what i read in the LS1_tunning_info_1.40r.doc and the info i gathered about tunning the Idle you first :

1- set idle RPM.

2- raise the spark table(s) by the needed amount of timing advance without
causing knock retard.

3- set the IAC counts.

4- tune the IAC steps VS effective area.

5- tune the IAC steps VS. effective area and idle airflow all together.

6- do the SD tuning using the WB then enable the MAF and dial it (all this in
this in step # 6 to get correct VE, LTFT, STFT and tunning the WOT (PE table) at all
RPM's).

after you do the previous steps then tune the LTIT, the STIT and the RAF table.

7- tune LTIT, STIT and the RAF table.

an expert can chime in if what i wrote is not correct.

what would you say EC_Tune?

Abdullah

[EC_Tune]

Abdullah, good to talk to you today!

Idle tuning addendum:

Set all the Adaptive Idle parameters to Zero See HERE as well so that only the STIT is active. Once you have the Base Running Airflow set correctly, put the MAX values back to stock and put the Min values to -.5 g/sec or less. The STIT (idle airflow trims) will still adjust things appropriately but it will not store a value less than -.5 g/sec

Generally you do not need to adjust the IAC steps VS effective area unless you have a larger than stock throttle body.

[Abdullah]

thanks for the info EC_Tune.

[white_shark]

I had some stalling issues with my cammed vette LS3,
the tuner said a small hole must be drilled in order to eliminate all my idling & stalling issues...

after a lot of reading, I concluded the following solutions that worked:
1- drill a small hole in the throttle blade ... or
2- open the throttle some via the set screw and do TB reset procedure

my question now, Is it possible in anyway to fix this problem via tuning using HPTuners & without doing any of the above methods?

I hate to make a desision when there is another better available desision that will give the same results!

Thanks in advance all

[1FAST5.3]

Hey guys im a newb and ive read these post and im still lost on how to fix my idle, it idles fine in park and nuetral, but idles up in gear and when i pull up to a stop it idles up and stays there, how do i fix this. if all else can someone point me in the right direction of where its explained where a dumbass can comprehend it.

[RWTD]

I had some stalling issues with my cammed vette LS3,
the tuner said a small hole must be drilled in order to eliminate all my idling & stalling issues...

after a lot of reading, I concluded the following solutions that worked:
1- drill a small hole in the throttle blade ... or
2- open the throttle some via the set screw and do TB reset procedure

my question now, Is it possible in anyway to fix this problem via tuning using HPTuners & without doing any of the above methods?

I hate to make a desision when there is another better available desision that will give the same results!

Thanks in advance all

You have a Vette, and you're going to open the TB via a set screw??? Unless you have a conversion setup, you don't have an adjustable TB in you vehicle. You have an ETC system.

If you have a Gen4 vehicle (basically '05+ vehicles), or in your case possibly an '08 or newer LS3 Vette, you should NEVER have to drill the TB to get it to idle properly. The Gen4 ETC system is brutally fast and responsive, so all you need to work on is your fueling, idle spark, and your idle parameters.

[VYSSWagon]

What time is it when your tuner says to you "a small hole must be drilled in the throttle blade in order to eliminate all idling & stalling issues..."?

It is time to find a new tuner!

There are a lot of "butcher tuners" out there willing to take your money for a "pretty color" dyno printout. I was at a Vette club meeting a few months ago, and one of the guys started his newly cammed C5 (to show off, as you do!). He had to sit in the car and blip the throttle to keep it running. The guy paid good money to get the cam installed and tuned, it makes reasonable HP (sounds really wicked), but won't idle! His tuner said "With that size cam, you will just have to live with it...", what a load of cr@p!! (I've only just joined, so didn't really want to say to much, but told him he does need a new tuner...)

This is a fantastic thread guys. Thanks to everyone who has contributed.

[bluebyu8484]

And for startup leanness when the engine is hot:

Attachment 4694 Attachment 4695 Attachment 4696 Attachment 4697 Attachment 4698

Is this meant to create a more lean condition or remedy one? Also, my LTIT is pretty much stays at -.4..... is that ok? I have used the RAF adjustment table and the STIT is close to zero.

[nexstar7]

holly crap! that was great reading. unfortunately my tuner drill a hole in the tb. god damm! anybody know a tuner that will follow the right way of tuning with hp in New York. i feel drained of the bull shit.

[S2H]

holly crap! that was great reading. unfortunately my tuner drill a hole in the tb. god damm! anybody know a tuner that will follow the right way of tuning with hp in New York. i feel drained of the bull shit.

drilling a hole is not wrong...
but it can be avoided on many cams
when you get into a large cam.. that is looking for a lot of airflow at idle..you need to get more air in there somehow..
if your cold start IAC is maxed out... then you definitely need to figure out more air somehow...
on fbody's you can use the TB set screw...but if you get past .76 volts, you get a DTC and it throws a bunch of stuff out of whack(even if you turn off the DTC)
so sometimes drilling is the only option.

I personally prefer to drill a small second hole in the TB on a large cam.
My 234/242 (total duration 285/293) (which turns out to be 18* of overlap) has a second hole...and needs it.
puts my hot IAC back in the 60ish range which allows for the most efficient movement of the IAC motor and pintle which makes it easier to self correct for airlfow at idle

there are many ways to cook an egg... I cook mine with a hole in it on a larger cam
a smaller cam with less overlap, I go for the TB Set Screw
baby cams can go without a hole or a set screw adjustment sometimes

ETC vehicles usually can go without any hole at all unless its a monster cam

[=fast=]

^^^^^i have a camaro with 228r cam..... 228 to 228...... 588 to 588, the car drives fines, runs fine..... the problem is when i rev it on neutral or when i make a burn out, the rpm's comes down then the car dies...... What can i do to fix that problem?

[CarsonTech]

RAF tuning if that hasn't been done, of course. Sometimes lightweight flywheels can exacerbate the problem and RAF tuning will not totally cure the problem depending on other mods. Sometimes you may have to fudge around with timing and fueling too. Make sure your injector data is spot on too.

[1nastyz06]

drilling a hole is not wrong...
but it can be avoided on many cams
when you get into a large cam.. that is looking for a lot of airflow at idle..you need to get more air in there somehow..
if your cold start IAC is maxed out... then you definitely need to figure out more air somehow...
on fbody's you can use the TB set screw...but if you get past .76 volts, you get a DTC and it throws a bunch of stuff out of whack(even if you turn off the DTC)
so sometimes drilling is the only option.

I personally prefer to drill a small second hole in the TB on a large cam.
My 234/242 (total duration 285/293) (which turns out to be 18* of overlap) has a second hole...and needs it.
puts my hot IAC back in the 60ish range which allows for the most efficient movement of the IAC motor and pintle which makes it easier to self correct for airlfow at idle

there are many ways to cook an egg... I cook mine with a hole in it on a larger cam
a smaller cam with less overlap, I go for the TB Set Screw
baby cams can go without a hole or a set screw adjustment sometimes

ETC vehicles usually can go without any hole at all unless its a monster cam

So would it be correct to adj the TB set screw to get the IAC in range and then slot the holes for the TPS to get the voltage back in range? Would that cause any additional issues?
Thanks

[S2H]

So would it be correct to adj the TB set screw to get the IAC in range and then slot the holes for the TPS to get the voltage back in range? Would that cause any additional issues?
Thanks

I dont see any issues with that...
a lot of guys like the TB set screw......just have to be careful not to get past .74 volts(If I remember correctly its at .75 that it starts screwing stuff up)

you would want to get it to the max you can with the TB screw...and then drill past that...
if you happen to go slightly too big with the drill... then you can always back down the set screw a little

[S2H]

^^^^^i have a camaro with 228r cam..... 228 to 228...... 588 to 588, the car drives fines, runs fine..... the problem is when i rev it on neutral or when i make a burn out, the rpm's comes down then the car dies...... What can i do to fix that problem?

sounds like it needs more air at Idle...
Running Air Flow tables need to be upped most likely or you need to crack the TB Blade slightly to allow more air in