Bad cold starts all the sudden... WTH?

[Humvee]

Recently, my car has been having poor cold starts. Normally on cold starts, my car will roar to life up to 1,500 and settle down to 1,000 after a brief while. Now, it doesn't shoot up... it goes straight to 500-600 RPMs and since the engine is cold, it tries to stall. The only changes that happened is that the air temperature around here is somewhat warmer now... It ran great when it was 30 degrees. But now that it's around 45-50 degrees outside, the car just doesn't like to start as well as it did... Not sure if it's temperature related, but it's the only change that has occurred.

Now the question is... what is causing this to happen. It happen almost suddenly. What sensor, if there is one, that tells the ECU that the engine is dead cold? Or is there
something else that I should look for? Does anyone else have this type of problem or
solution? Help!!!

Thanks,
Humvee


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1989 IROC-Z Convertible
305 automatic
White with black top

http://www.mindspring.com/~humvee/camaro.html

Never anger a Dragon, for you are crunchy and go well with Brie.

[Napsterbator]

Try Checking your Idle Air Control valve underneath your throttle body. Clean any carbon off and re-adjust the plunger. If your temp sensor was totally defective, your ecm would have already thrown a code. But it still doesn't mean your temp sensor is working effectively.

[Humvee]

Hmmm... I better look at the IAC. Only problem is that I never gotten around to working on the IAC. Is there an article on how to remove it and stuff?

------------------
1989 IROC-Z Convertible
305 automatic
White with black top

Mods:
K&N filters
Gutted airbox
12" Kenwood in Q-Logic box

http://www.mindspring.com/~humvee/camaro.html

Never anger a Dragon, for you are crunchy and go well with Brie.

[Napsterbator]

I'm not sure if there is an article but its really simple to remove. But whatever you do make sure you buy a new gasket for your IAC. It probably has a lot of carbon build up on the plunger. Re-adjust by pressing down on the plunger with your thum till you get the desired depth or when it "clicks". Still if you are careful, just try cleaning the plunger with carb spray and try not to tap on the plunger to keep its stock adjustment.

[Humvee]

Ah, thanks man. I'll tackle the job this weekend while I have time off work. What happens if I do move the plunger? Do I go ahead a reinstall it or is there a procedure I have to go thru to reset the IAC?

------------------
1989 IROC-Z Convertible
305 automatic
White with black top

Mods:
K&N filters
Gutted airbox
12" Kenwood in Q-Logic box

http://www.mindspring.com/~humvee/camaro.html

Never anger a Dragon, for you are crunchy and go well with Brie.

[Napsterbator]

It's ok if the plunger moves a little, just don't hit the IAC on top of a table or something to make it click. Otherwise you should be fine. Also, Spray a little carb spray where the IAC port on the throttle body. Don't flood it with carb spray but a couple of shots should clean it. Also, Just spray the tip and spring of the IAC valve. Hope that helps

http://www.3rdgen.org/ubb/smile.gif

[Humvee]

Thanks! You've helped me out a lot! http://www.3rdgen.org/ubb/biggrin.gif

------------------
1989 IROC-Z Convertible
305 automatic
White with black top

Mods:
K&N filters
Gutted airbox
12" Kenwood in Q-Logic box

http://www.mindspring.com/~humvee/camaro.html

Never anger a Dragon, for you are crunchy and go well with Brie.

[Napsterbator]

Your Welcome http://www.3rdgen.org/ubb/biggrin.gif