Idle problem when cold out?
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Idle problem when cold out?
Now that it is getting colder out my truck does not idle right when first started up. It does fine after the truck warms up. It is not givving any codes or anything like that. I was thinking something might be wrong with the tps but really have no clue. If anyone might have an idea I would really like to hear it. Thanks
Tim
Tim
Lead Driver
Joined: Sep 2006
Posts: 7,907
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Your close but no cigar.
It's the IAC intake air controller not opening up to admitt extra air needed for cold start and higher idle.
Remove it and use throttle body cleaner sprayed inside to clean out the gum and dirt. Make sure the pintel moves that allows air to bypass.
Next clean the throttle body plate area. Hold the throttle open so you can spray all around the plate area until it runs out clean.
Reassemble and wait a while to start until the cleaner has a chance to evaporate.
I would do the following procedure to be sure the PCM learns quickly that you corrected the issue.
Start the motor with the lights on and heater motor running on high.
This mimiks the max load under cold start conditions. (alternator load and battery recharge) loads.
Allow the motor to heat to op temp.
Then run the truck about 5 miles, then do some restarts without lights and heater so the PCM learns hot restarts and you should have good starts under all conditions if there are no other issues .
Good luck and let us know how it turns out.
It's the IAC intake air controller not opening up to admitt extra air needed for cold start and higher idle.
Remove it and use throttle body cleaner sprayed inside to clean out the gum and dirt. Make sure the pintel moves that allows air to bypass.
Next clean the throttle body plate area. Hold the throttle open so you can spray all around the plate area until it runs out clean.
Reassemble and wait a while to start until the cleaner has a chance to evaporate.
I would do the following procedure to be sure the PCM learns quickly that you corrected the issue.
Start the motor with the lights on and heater motor running on high.
This mimiks the max load under cold start conditions. (alternator load and battery recharge) loads.
Allow the motor to heat to op temp.
Then run the truck about 5 miles, then do some restarts without lights and heater so the PCM learns hot restarts and you should have good starts under all conditions if there are no other issues .
Good luck and let us know how it turns out.
New User
Joined: Sep 2010
Posts: 10
Likes: 0
Try this
My truck was idleing low and running rough when cold as well. Took it to my mechanic and he ran the code, which came up as random cyl misfire. He replaced the ICM (Idle Controll Motor?) and it runs like a champ. No if i can only figure out why my heat blows cold unless im moving. Will post a new thread on this.
Lead Driver
Joined: Sep 2006
Posts: 7,907
Likes: 143
For what it may be worth, on Ford motors up to but not including electronic throttle control that use the IAC device,
the INTAKE AIR CONTROLLER (IAC) is not a motor (icm).
It is an electrical solenoid that is pulsed by the PCM against it's internal spring to control the air bypass amount.
Less or more pulsing controls the bypass amount and is capable of controlling the motor idle speed as close as +/- 50 RPM.
The PCM uses the crank sensor as a Tach signal input.
The PCM compares it to an idle table.
When not within limits, the PCM pulses the IAC to either open or close a small amount for correction to bring the idle rpm within table limits and keeps on hunting to make the idle stay within table limits.
The idle table limits are able to be altered by the cylinder head temperature input, AIR sensor in the intake tube as well as overheating input signal and other computer actions for total control of the idle speed according to the engine needs at any given time..
Sticking IAC impedes all these actions.
the INTAKE AIR CONTROLLER (IAC) is not a motor (icm).
It is an electrical solenoid that is pulsed by the PCM against it's internal spring to control the air bypass amount.
Less or more pulsing controls the bypass amount and is capable of controlling the motor idle speed as close as +/- 50 RPM.
The PCM uses the crank sensor as a Tach signal input.
The PCM compares it to an idle table.
When not within limits, the PCM pulses the IAC to either open or close a small amount for correction to bring the idle rpm within table limits and keeps on hunting to make the idle stay within table limits.
The idle table limits are able to be altered by the cylinder head temperature input, AIR sensor in the intake tube as well as overheating input signal and other computer actions for total control of the idle speed according to the engine needs at any given time..
Sticking IAC impedes all these actions.
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