C4VetteLS1

Ive got a Dynojet chassis dyno at our shop. 00' Firehawk with stage 2 heads, ls6 intake, headers, 224/224 TR Camshaft etc.

The car doesnt idle well at all. (surges and dies alot, smoothes out occasionally) and the car is running pretty rich.

Where do i start to fix the idle problem and i can use the wideband o2 to do all the tuning.

Mekkadon

iTrader: (3)

Is it an A4?

miner_49

You might try starting with
http://ls1edit.slowcar.net/tuning.html

Cal

iTrader: (1)

TTT

Texas Terminator

have you drilled your tb yet?

LASTLS1

iTrader: (7)

Is drilling your t/b just a bandaid for inproper tuning, or something that should be done with a h/c car? because my car also idles like crap! so rich at idle it will burn your eyes out. Thanks Andy

LASTLS1

iTrader: (7)

Also what size hole to start with and any specil spot in the butterfly? Thanks

LASTLS1

iTrader: (7)

special, I know!

FastAl

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Texas Terminator:
<strong> have you drilled your tb yet? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Why would anyone drill the TB when they have LS1Edit?

Turn the idle up via LS1Edit my 100-200 rpms and see how it runs!

Doc99SSx

I think that the issue is with the IAC position. In order for a cammed engine to idle at a smooth but higher RPM, the IAC may not be able to adjust out to a far enough position whereby it would be out of Spec and set an SES code.

In order to idle at a higher RPM and keep the IAC position in a happy range, on some engines it is appropriate to drill a small hole in the TB plate.

From the first post: the root cause for a surging idle is many times a vacuum leak. Since the intake was changed, I would first suspect a vacuum leak.

<small>[ February 27, 2003, 11:00 AM: Message edited by: Doc99SSx ]</small>

2001CamaroGuy

iTrader: (6)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by FastAl:
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Texas Terminator:
<strong> have you drilled your tb yet? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Why would anyone drill the TB when they have LS1Edit?

Turn the idle up via LS1Edit my 100-200 rpms and see how it runs! </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Drilling the TB is essential to proper operation.

With LS1Edit you adjust the idle up BUT......what is one of the ecential component of the engine running?

AIR....

The faster the engine is going to run, the more air that is needed.

At idle, the throttle blade is closed so air has to get in through another way. If enough can't through the TB hole, then the IAC motor must back out more. Once the IAC count gets up too high, the engines idle quality starts to deminish and drivability suffers. It will surg and die and all around be a real B*TCH <img border="0" title="" alt="[Mad]" src="gr_images/icons/mad.gif" /> ! (believe me.....I have spend DAYS playing around with trying to make my TR 224/224 112 LSA cam idle at 650 RPM.....I'm still not there yet <img border="0" title="" alt="[Frown]" src="gr_sad.gif" /> ....).

This is why you must drill out the TB. You drill it step by step till the IAC count comes back down into the mid 30s.

LS1Edit does a lot, but YOU (the person with the tools) still has to do the manual work.

Chris

<small>[ March 01, 2003, 12:30 AM: Message edited by: 2001CamaroGuy ]</small>

SSprayn

My car idles ok but I have the idle set at 950. I am hoping to get Ls1 edit soon and get rid of this Ed Wrigth junk tuning I have right now. My car runs insanely rich and he wants 200 for an adjustment. So hopefully Edit is worth the 550

Texas Terminator

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by SSprayn:
<strong> My car idles ok but I have the idle set at 950. I am hoping to get Ls1 edit soon and get rid of this Ed Wrigth junk tuning I have right now. My car runs insanely rich and he wants 200 for an adjustment. So hopefully Edit is worth the 550 </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">good luck! <img border="0" alt="[jester]" title="" src="graemlins/gr_jest.gif" /> Ed locks the pcm so you have to go back to him.

Texas Terminator

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by FastAl:
<strong> </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Texas Terminator:
<strong> have you drilled your tb yet? </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Why would anyone drill the TB when they have LS1Edit?

Turn the idle up via LS1Edit my 100-200 rpms and see how it runs! </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">and you obviously don't have a clue! besides, maybe they don't want their cars to idle at 900 rpm. with the added airflow, the iac can't keep up. it is only for fine idle adjustment. the hole in the throttle plate is designed into the whole setup from the factory for a base idle and the iac takes care of the rest.

Cal

iTrader: (1)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LASTLS1:
<strong> Also what size hole to start with and any specil spot in the butterfly? Thanks </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Most people just drill out the existing hole larger, but I've heard of drilling a new small hole to the side. I guess that way you could always return to the stock configuration by just plugging the new hole.

NoGo

iTrader: (2)

You don't have to drill the throttle body to allow enough air to the engine. I tune probably some of the biggest cams in the business, and I don't have to drill the throttle body at all.

Tune the following tables.

IAC in Park: Adjust all temperatures greater than 20 C to 19
Idle Air in Gear: All numbers lower than 9, set to 8.50.
Idle Speed: Set idle speed to 1000

The IAC will not run out of travel on big cammed cars. The equivilant IAC position for a 240+ cam is about half open. With cams that you are dealing with, I'm sure you will have plenty of room.