shane buss

Guys i know this has been beat to death, but i still cannot find the answers im looking for anywhere.

I have a hotcam and ls1edit, and although ive raised the idle and it is a little better, it still will not start without giving it gas, and it still stumbles sometimes. Idle is already at around 875 rpm across the board, i hate to raise it more. Is there something like Less timing, or changing the IAC park position to 0 that might help? What about changing the fuel at idle?

My iac counts are great, ive drilled the TB out and raised the idle screw. Ltrims look good also. Car is a A4 with a 2800-3000 stall converter. I'm wondering if the Ed Wright could fix this. People that have had their PCM custom tuned, do you have this problem still? I've seen a few responses that say there is no way to fix the Hot start problem, but im not giving up yet. ;-)

The hotcam isnt even that big!
Thanks,
Shane

shane buss

I just wanted to add I noticed on the STOCK LS1 file, it has a HIGHER IAC PARK position for colder temps. This doesnt make sense to me.. when its colder, would you need LESS air at idle?

I realized i had been trying the wrong direction on mycar with IAC, so i just tried RAISING the IAC park position significantly for hotter temps, which should give me more air. I think with a big cam you have a tendency to run rich at idle, thus causing the problem. we'll see.. any insight? what is the range of the IAC motor? 0 to what?

shane buss

FINALLY! MY CAR STARTS FINE WITHOUT DYING WITH A HOTCAM! Even with A/C on. that fixed it. Raise the IAC park position for warmer temps. Maybe the reason they have IAC position higher for colder temps in a stock program is so your car will idle higher when cold and warm up faster.

I cannot beleive no one has done this before, or at least there are no posts about it.

Ragtop 99

iTrader: (7)

I haven't messed with the table because once again, Carputing put zero info about the table in the user's manual. <img border="0" title="" alt="[Roll Eyes]" src="images/icons/rolleyes.gif" /> A few questions for you:

1) How much did you change your table and at what temps?

2) Have you figured out what the units mean? It does not seem to correspond to IAC counts that I typically see.

3) Did you change the IAC in Gear table? If yes, what did you change was idle noticably smoother?

You're the trailblazer here. <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

shane buss

I changed the IAC Park Position for values 20C and up to "21.00"..

I changed the IAC In Gear from 20C up by a percentage.. what percentage i cant remember. I think like 120% or 130%. my 260C value IN GEAR is 9.30, and Neutral is 9.00

Anyway after doing this i was able to lower my idle from 875 to 800, and it still runs PERFECT and starts PERFECT... i could probably lower it anymore. I still cant beleive no one has found this out before.. It kicks ***, i almost have a HOtcam idling like stock with 2 programs.

Shane

98TAauto

iTrader: (2)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by shane buss:
<strong>FINALLY! MY CAR STARTS FINE WITHOUT DYING WITH A HOTCAM! Even with A/C on. that fixed it. Raise the IAC park position for warmer temps. Maybe the reason they have IAC position higher for colder temps in a stock program is so your car will idle higher when cold and warm up faster.

I cannot beleive no one has done this before, or at least there are no posts about it.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I see you fixed it <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> Congrats... also you might have just found a break through <img border="0" title="" alt="[Wink]" src="gr_images/icons/wink.gif" /> Im not messing with mine because i finally got the car running fine now by drilling <img border="0" title="" alt="[Smile]" src="gr_stretch.gif" />

98TAauto

iTrader: (2)

Heck, i went to edit just to look at it, and they dont have the IAC in park implemented for a 98?? WTF?

but idle air in gear works??? Question.. would mult all of those cells by 30% help any with surging when i put the car in gear? Its not a big issue so i doubt i mess with it.

But what are the stock IAC's set at in the PARK one? Is there even a need to drill the TB if you have this option now?

shane buss

It might only be on a newer flash file that you can change the IAC position in gear? Maybe only a newer pcm? I'm not sure.

All i know is even when i had it where it idled pretty good when runnning, i still had to hold my foot on the gas to start it. Thats what the IAC in park fixed.

IAC in gear fixed the surging... I would imagine that you could get by without drilling you TB at all, but maybe not because im not sure HOW far you can adjust the IAC motor. I would try it but since mines already drilled, there's no going back. I would definitely try raising the table by 30% and see what happens. Worse case scenario is you change it back. I'm curious to see what other peoples results are doing the same thing.

I only changed mine for temperatures above 24, because when its cold it ran pretty good. I am going to go back and raise the pre-24 degree values A LITTLE, but as of now they are stock.

DriveATransAm

i find that mine only likes to crank and stay running when its been sitting overnight- and you read my responses to your other post. i really hope this fixes it.

shane buss

I'll bet ya money it will ;-)

As long as you have that IAC park position adjustment. Someone (hope it wasnt you) with a 98 said he didnt have that option, only IAC in gear.

Im gonna try to lower my idle to 750 with hotcam and see how it goes. <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />

Ragtop 99

iTrader: (7)

I'm definitely going to experiment with it and see if I can bring my idle down a bit with it.

Ragtop 99

iTrader: (7)

I played with it and my results were not as positive as Shane's.

I raised the IAC in Park, using 23 from 0*C - 60*C dropping to 15 at 100*C. I still get some surging that goes away with a blip of the throttle. It's hard to test how the car does when cool because of the cool down time since I don't have a manual fan switch.

I raised the IAC in gear by a maximum of 3.5 (40* C) and with most settings raised by 2 - 2.5 and while the idle is a little better, the car feels like it is on cruise control when I lift my foot off the gas if I'm down at 1500 rpms. The good news is that I had some lift throttle cam surge that has been reduced. Off-idle throttle response seems better too. I'm probably going to reduce the values by .5 - 1.0 and see if I can strike a better balance. The other solution may be to change the Throttle Follower decay values. Anyone mess with that yet?

shane buss

"I raised the IAC in Park, using 23 from 0*C - 60*C dropping to 15 at 100*C. I still get some surging that goes away with a blip of the throttle."

I set mine to 21 from aruond 60 to the top end of the table the max temp of the table.

just keep playing with it, im sure youll get it. I'll post my exact values for both tables tommorrow. WHat cam do you have?

Ragtop 99

iTrader: (7)

Shane:

First I tried using 21 and stepping down to 13. That didn't elimininate all of the surging so I tried 23 (setting of 0*C) to see if that would help, but it made no improvement over using 21.

I have ARE's "secret" 232 cam so it is a bit larger than the Hot Cam. I may try the idle relearn before changing the specs.

Making the Edit changes would have probably allowed the use of a smaller TB hole.

Ragtop 99

iTrader: (7)

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by shane buss:
<strong>i used 21 across the board from lik 60degrees up.. have you tried that without stepping down?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">No. I wanted to try and follow the factory curve, just raise it up some. I was concerned that it would be a huge drop when going from P to D when the car was hot if I used 21 accross the board.

gojo

iTrader: (12)

Shane, all things equal you do need less air when cold. Also you need to increase throttle position. Think about a carb. The choke closes and richens the mixture and sets the throttle higher.

shane buss

right, thats why by raising the amount of air the engine gets when hot (the iac position) it fixed the hot start/surge problem.

cold air is more dense, so you dont need as much everything else the same.

I was confused as to why the factory settings give you more air when cold, not when hot!

shane

shane buss

i used 21 across the board from lik 60degrees up.. have you tried that without stepping down?

Ragtop 99

iTrader: (7)

Well after several experiments, I went back to higher settings in gear. It got rid of the lift throttle surge at low rpms, although it does want to coast at 1300 - 1400 rpms. As I brought the settings down closer to stock, I wasn't improving coast down much, but the surge was becoming more of an issue. I think a smaller TB hole would have given me more flexibility.

Ragtop 99

iTrader: (7)

I closed my TB blade by 1.25 turns to reduce air flow. That helped reduce the cruise control effect. Clearly a smaller TB hole is adequate if you change these settings. I also increase the P/N follower delay to .25 seconds below 6 or 8 mph.