Engine Stalls when A/C compressor engages

Tiny
COORDINATOR15
  • 2004 CHEVROLET TRAILBLAZER

Electrical problem 6 cyl Two Wheel Drive Automatic 65,294 miles

I have a 2004 Chevy Trailblazer which has been great with normal maintenance. My battery was hard hard cranking and needed to be replace, so I stopped by the local parts store and bought a new battery last weekend and replaced my battery.

Here is where the problem started, that night after changing my battery, I went to use the defroster. When the A/C compressor engages at idle in park or neutral every 5 to 10 seconds the idle drops and will either almost stall the engine or occasionally does stall the engine. This happens in drive as well, and when driving, since the RPM drop and come back up, the vehicle surges at low speeds. The RPM drop only occurs when any A/C component is on (A/C, defroster, or re-circulation), when just the vent is on, the RPM does not drop and the engine run fines.

Please help me with this question, it seems like this is not a one of a kind problem.

Thank you in advance!

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Saturday, January 26th, 2008 AT 8:52 PM

10 Replies

Tiny
PEAR69
  • MEMBER

Sometimes when you disconnect the battery the engine must go through 25 running cycles to reboot the computer. OR your IAC valve may be failing. Be sure your battery connections are tight and clean.

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Sunday, January 27th, 2008 AT 6:09 AM
Tiny
BRIAN 1
  • EXPERT
  • 1,063 POSTS

Might want to try this.found bulletin #1878920. Engine Stalls When Air Conditioning Is Turned On At Idle - keywords HVAC rough condition CJ2 CJ3 surge. Engine may stall with the air-conditioner on and or while adding additional loads to the engine at idle. An example of an addition load would be turning the steering wheel left or right with the air-conditioning on. This type of stall usually occurs during idle or slow parking lot maneuvers. This concern may not set any diagnostic trouble codes.

Clean the throttle body bore and the throttle valve plate using a clean shop towel with GM top engine cleaner, GM P/N 1052626 (Canadian P/N 993026) or AC-Delco Carburetor Tune-Up Conditioner, P/N X66-P, or an equivalent product.

Here is a guide to help you see what I am talking about

https://www.2carpros.com/articles/throttle-actuator-service

Please let us know what happens.

Cheers

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Sunday, January 27th, 2008 AT 5:16 PM
Tiny
PEAR69
  • MEMBER

When you turn on the A/C, the A/C compressor kicks in. This puts a small load on the engine. The RPMs should go down a little. However, when you disconnected the battery, all the sensors that compensate for this load- lost power. The IAC valve can very easily cause the problem you describe and may need to be reset. To do this follow the following--1: disconnect and remove the IAC valve. 2: measure the distance from the tip of the pintle to the mounting flange. It should be 1 and 1/8 of an inch, if not push the pintle in so it is. 3: re-install the valve. 4: cycle the key on for 10 seconds and off for 10 seconds. This resets the valve. 5: Start the engine (do not press the gas) and let it idle for 5 minutes, then shut it off for 30 seconds. Then start the engine again and drive around for a while and test the A/C. During all these steps do not turn on the A/C until driving around during step 5. Let me know how you make out..

https://www.2carpros.com/articles/stall-at-idle

and

https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac

BTW: the IAC valve is the idle air control valve. This valve controls the amount of air allowed to bypass the throttle plate when the throttle plate is closed or at an idle position--not necessarily at engine idle--it's at throttle position idle.

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Tuesday, January 29th, 2008 AT 1:03 AM
Tiny
JENNCRRT
  • MEMBER

I have a 2004 also and it was doing the EXACT same thing.

Sure enough, cleaned the throttle body and problem solved! I also read elsewhere that this is caused from not using "top tier" gas. (Ex. Shell, Cheveron) I have always used Walmart, or Sam's. I have joined the trailvoy forum! It is a great site. Has anything you would ever want to know about Trailblazers from other owners. Browsed this site before I found it and thought I would share!

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Thursday, February 21st, 2008 AT 3:22 PM
Tiny
DPOTTER
  • MEMBER

Your problem is a dirty throttle body. Had the same same happen after changing the battery. A good friend sells chevys and asked the service manager to confirm what I found on line. Over time the car's computer adjusts for driving conditions, engine wear and ect. With a dirty throttle body (which is normal) the computer adjusts. When the battery is changed, it re sets to factory settings. So the computer thinks you have a brand new vehicle, with a clean throttle body and regulates fuel/air to that. So it stalls when anextra load is applied. A two doller can of carb cleaner and about 20 minutes will fix u right up. I'm so sick and tired of people on here spouting off with what they think is the answer. I had no clue till I started looking on line. 20 years ago would have been out at least 500 bones at the dealer for this. For all it's fualts, the internet is a god send.

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Tuesday, June 17th, 2008 AT 7:20 PM
Tiny
MSM1462
  • MEMBER

The dirty throttle body is the cause of surging after disconecting the battery. It makes sense to me since my TB has 105,000 miles on it. To help others out, this happen to me when the defroster was on. Keep in mind, difrost mode atoumaticly turns on the AC if it is warm enough out. This made it dificult tofind the cause. Would not surge or die in the colder weather. 25 degrees is the threshhold give or take a little.

TB runs great with a clean Throttle Body. It was easier to clean by removing it. Four bolds, vacuum hose and a wire conector to remove. It also helps prevent washing the grime into the monifold.

Love the internet!

Happy Trailblazing! : )

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Tuesday, January 12th, 2010 AT 10:58 PM
Tiny
GHOSTRIDERMC1
  • MEMBER

I know this post was created a while back but I would like to say it was extremely helpful! When the battery when out and I had to replace it the car would almost die when the A/C tried to engage. I suspected a compressor but before I contacted anyone I used the old faithful "Google" and found this thread. After multiple unsuccessful cycles I decided to purchase some throttle body cleaner. It took about 1 hour to take apart/clean and put back together. Low and behold, praise God, the problem immediately disappeared and the car runs like new!

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Saturday, August 14th, 2010 AT 10:11 PM
Tiny
DANNO28
  • MEMBER

I have to agree it was very helpful. I have a 2003 trailblazer and had to replace the battery. When I went to use the a/c at low speeds the rpm's would drop and the truck would stall. Figured it had to be related to replacing the battery somehow and found these posts. Cleaned my throttle body and problem solved. Better then paying a mechanic to fix it. Thanks alot guys

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Saturday, May 28th, 2011 AT 2:12 AM
Tiny
AWFCOUGAR
  • MEMBER

For the most part this response would be correct. However the 360 platform does not contain an IAC. Cleaning the throttle body is going to be your 99.9% cure all to the problem.

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Thursday, May 8th, 2014 AT 7:24 AM
Tiny
HECTOR1974
  • CHEVROLET TRAILBLAZER

Hello and thank for the help
mi car is a chevy trailblaser 2004 and I have 58422mile
i have some tipe of electric problem, yestuday I smell
some relly bad odor it was like a dead animal and mi
dad see some smoock coming out of the battery.
I bay a new battery and I instaled. To this point every
thing is normal, I test the battery and it show 12.6
then I instaled and I test again and it show 14.4.
I test all the electricity into the car then I find this.
Every time the I turn the a/c on the aceleration of the car drop to 200 rpm or less and I test the alternator again. And it goes to 13.5.
Then I see the every time. The a/c compresor try to
star the rpm goes down and when the compresor stop the rpm come back to normal.
I know a little mechanic, but this time i'm comfiuse
in bitween the alternator and some part of the a/c.
Please helpme.
Then I ask this question because, some time. The I go
to eny taller I find the I know some of the problems
better then the people who work in there.
Then I feel the people is not prout of his job eny more.
Thank you to all the mechanic who answare this.

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Wednesday, August 23rd, 2017 AT 12:25 PM (Merged)

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