Cold start issue LM7
04-13-2012, 08:52 AM
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Car: 1998 Trans/Am, 1989 RS Camaro
Engine: LS1, LQ9 6.0
Transmission: 4L60E, 4L60E
Axle/Gears: 2.73, 2.73
Cold start issue LM7
The last 2 mornings the camaro has run ruff for a few seconds on a cold start. I have no codes and the sensor readings when the engine is cold are correct. This moring the coolant was 60 deg. and the IAT was 62 deg.
This morning it started then the idle dipped really low and came back to normal and ran fine, yesturday it was a lot more dramatic and lasted a little longer.
Only thing I can think of is to clean the IAC. Can you clean it with brake cleaner? By that i mean the sensor its self not the TB, I know I can clean the TB with it I just dont want to kill the IAC with it.
This morning it started then the idle dipped really low and came back to normal and ran fine, yesturday it was a lot more dramatic and lasted a little longer.
Only thing I can think of is to clean the IAC. Can you clean it with brake cleaner? By that i mean the sensor its self not the TB, I know I can clean the TB with it I just dont want to kill the IAC with it.
04-14-2012, 10:07 AM
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Car: 1998 Trans/Am, 1989 RS Camaro
Engine: LS1, LQ9 6.0
Transmission: 4L60E, 4L60E
Axle/Gears: 2.73, 2.73
Re: Cold start issue LM7
Really? No one... its still doing it. It also has horrible throttle response when first started.
04-15-2012, 02:07 PM
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Car: 91 RS
Engine: LTwon
Transmission: T-56
Axle/Gears: Both
Re: Cold start issue LM7
Might as well just replace it, mine was pretty cheap. Mines and LTx but it shouldn't be much diffrent
04-18-2012, 10:25 AM
#5
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Re: Cold start issue LM7
how's your tune? mine is pretty sluggish until it warms up to operating temp on the mail order tune.
04-19-2012, 05:27 AM
#6
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Re: Cold start issue LM7
i would also suspect your tuning is off as well... if it runs fine as soon as it warms up that is probably really an indication of it runs fine once it enters closed loop control (ie using the oxygen sensors as feedback for fuel trim to get correct AFR)
on cold start with the water temp cold and oxygen sensors cold both need to warm up prior to entering closed loop. the computer therefore does open loop control that counts on your models for VE and other factors to run properly. idle control is much harder in reality than WOT.
if you haven't had your car tuned chances are the type of air inlet manifold etc is different than what the stock tune had programed for and the VE values are off etc that once it enters closed loop the oxygen sensors make up for by adding or subtracting fuel as needed
on cold start with the water temp cold and oxygen sensors cold both need to warm up prior to entering closed loop. the computer therefore does open loop control that counts on your models for VE and other factors to run properly. idle control is much harder in reality than WOT.
if you haven't had your car tuned chances are the type of air inlet manifold etc is different than what the stock tune had programed for and the VE values are off etc that once it enters closed loop the oxygen sensors make up for by adding or subtracting fuel as needed
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