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LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Cold Start issues

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Old 11-07-2017, 11:36 AM   #1
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Default Cold Start issues

So my CC503 1994 Trans Am has had this issue for a long time since the mail order tune. When the car hasn't been started over night or for a few hours the car is hard to start. When I turn the key the car fires right up but the idle is low and smells rich. Plus I have to slightly press the throttle until it can idle on its own. When its warm, like after running it to the store, it fires right up. Sometimes it will even stall if I roll to a stop light... Is this tune related or are there things I need to look into? Also while logging it the IAC is nearly pegged and trying to lower it using EEHack makes it nearly stall. No stored codes, new ac delco O2 Sensors, plugs and wires, etc... Thanks for the input!
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Old 11-07-2017, 12:27 PM   #2
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Most likely tune related. Contact your tuner.
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Old 11-07-2017, 12:36 PM   #3
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Most likely tune related. Contact your tuner.
I have, he said he can't do anything unless I have a wideband. The car runs great at the track other than that cold start issue.
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Old 11-07-2017, 01:00 PM   #4
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I don't know enough about tuning to agree/disagree. However I do know those who mail order like data received. Since this happens on cold startup the car is not yet in closed loop. It could be just depending on default parameters to idle that cam and it's not jiving. Mine too will not idle when cold, but only takes a few minutes before it idles on its own.
My suggestion is to refrain from using your ehack program, gather some data, send it to your tuner and have them try and figure it out.
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Old 11-07-2017, 01:08 PM   #5
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Also while logging it the IAC is nearly pegged and trying to lower it using EEHack makes it nearly stall. t!
pegged...like at 160?

do the IAC counts drop drop as car warms up?

maybe your IAC valve is defective or dirty and sticking. You could remove and use some TB spray cleaner on it and the orifice it goes into. Do not pull or push on the printle when cleaning....and if someone did it is dead.
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Old 11-07-2017, 03:26 PM   #6
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pegged...like at 160?

do the IAC counts drop drop as car warms up?

maybe your IAC valve is defective or dirty and sticking. You could remove and use some TB spray cleaner on it and the orifice it goes into. Do not pull or push on the printle when cleaning....and if someone did it is dead.
Yeah my IAC counts move up and down as it warms up, its just they stay near the 130 range from what I remember.
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Old 11-08-2017, 10:57 AM   #7
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Stock throttle body?
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Old 11-08-2017, 11:45 AM   #8
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Stock throttle body?
Yeah its stock, I contacted the tuner and he suggested opening the throttle blades up a little bit to get my IAC counts down. I tried lowering the IAC counts using EEHack and the car would stall out but increasing the IAC counts would increase my idle speed. I think that's my issue, the car is starving for air at idle... thoughts?
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Old 11-08-2017, 12:04 PM   #9
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If you open the blades, what is your throttle position sensor doing?
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Old 11-08-2017, 12:15 PM   #10
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If you open the blades, what is your throttle position sensor doing?
It operates normally. I know i'm gonna have to reset it after I adjust the blades to be more open.
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Old 11-10-2017, 01:03 PM   #11
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Alright update, adjusted my IAC down to the 15-30 range in closed loop like my tuner suggested and it fired right up this morning after sitting all night in 30 degree temps. No stalling or low rough idle! My TPS is set at .67v and smoothly rises to 4.5v according to: https://www.golenengineservice.com/d.../Adj%20TPS.pdf. It seems my car shifts sooner, is this the right voltage? I haven't drove the car that often lately so maybe i'm just thinking it shifts sooner.
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Old 11-10-2017, 01:28 PM   #12
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Did you adjust the TPS for that voltage? Not completely sure, but I think once you mess with the TPS it will influence auto trans shift points.
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