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Discussion Starter · #1 ·
Hello all-

Recently when I've started my 2009 MDX, I noticed my engine surging whenever I turn the AC on- if I turn the air conditioning off, the RPM surge stops...

no big deal right now as I can just simply drive with no AC (windows open etc./or just air with no AC blowing), but that's obviously just a temporary measure that will help prolong the inevitable fix needed....

Before I take my 2nd gen. MDX into the stealership, can anyone please suggest some potential causes for the symptom above- my MDX is actually due for an oil change so figure that I'll just go ahead and ensure that the stealership addresses this potential AC related problem, but want to know what some causes (low freon fluid, bad electrical part etc.) could be before I go into stealership land to potentially get served up some hot air/a nice bearting from the potential :surprise:money hungry service advisor?
 

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Discussion Starter · #2 ·
Independent mechanic will charge $50 to diagnose.

Acura Stealerships will charge between $72 and $147 to diagnose....can you say CHA-CHING?!!!! lol
 

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Is the surging continuous? Or just when the A/C kicks in? The A/C compressor requires a bit of oomph to get started so a short burst of extra power, I think, is pretty typical. And the compressor will cycle on and off as needed. Whenever I drive my BMW with the A/C on I can feel a definite loss of power, especially in the lower rpm range.
 

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Discussion Starter · #4 ·
Is the surging continuous? Or just when the A/C kicks in? The A/C compressor requires a bit of oomph to get started so a short burst of extra power, I think, is pretty typical. And the compressor will cycle on and off as needed. Whenever I drive my BMW with the A/C on I can feel a definite loss of power, especially in the lower rpm range.
hi,

the surging definitely only happens when I turn the AC on...(fortunately MI area weather has only been in the 60's to 70's degree zones lately, but I see the 80's and 90's creeping up in the near future)...so for the past couple days I've been commuting to work with AC off. :crying2:

i'm debating upon whether I should ask to have my AC fluid checked/'recharged', or if I should prepare myself for a potential compressor repair and/or replacement....:surprise:
 

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What is the RPM Fluctuation? it should not be above +/-50RPM when Hot.
If it does fluctuate above that perhaps the Compressor is Acting Up.
 

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Discussion Starter · #7 ·
What is the RPM Fluctuation? it should not be above +/-50RPM when Hot.
If it does fluctuate above that perhaps the Compressor is Acting Up.
On the RPM- thingy/dial thing (on the left) (while car is standing in park or if I'm stopped at a traffic light), as soon as I press the AC button to turn it on, the RPM meter will noticeably fluctuate from just over the 1 mark towards the zero- back and forth, almost giving off the impression the engine is struggling just to keep running-...as soon as I turn AC off, there is no RPM fluctuation and the engine returns to sounding normal again (not like it's struggling to run, just a moment ago while the AC was turned on) :frown2:

<center><img src="http://pictures.dealer.com/s/sussmanacuraadw/1513/b308707ef68765924ac16db1d625a70ax.jpg"></center>
 

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Discussion Starter · #8 ·
Is it specifically when you first start the vehicle?
it doesn't appear to be specific to only occurring while car is parked, even as I turned the AC on while waiting at the traffic light, and during that brief, approximate 10 second period during which I had tje AC on, the car's RPM meter was surging/struggling above and below the '1' mark, and the engine sounded like it was fading in and out...once AC was turned off, 2009 MDX engine resumed to sounding/running normally, with no more fluctuation on the RPM dial.. :crying2:
 

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I would guess just because there is no Check Engine code that the Compressor is malfunctioning...
In the best case scenario a proper A/C tune-up will get it back to shape.
In the worst case scenario you need a new A/C Compressor.
 

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Discussion Starter · #10 ·
I would guess just because there is no Check Engine code that the Compressor is malfunctioning...
In the best case scenario a proper A/C tune-up will get it back to shape.
In the worst case scenario you need a new A/C Compressor.
thank you very much your insight- this information is really helpful in having (pre-mechanic confrontation) and in helping me prepare/strategize the most cost efficient (and effective) approach towards dealing with this particular problem :29:

once I can eventually narrow down the problem (i.e. if it is the A/C compressor that needs to be replaced, will likely get the part/parts online then take it to my go to independent Honda/Acura mechanic), the next set of objectives will become much clearer :nerd:
 

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If you could try something like this:
Have someone near the engine bay (Hood Open) and make him/her listen to a specific change in sound when the compressor kicks in.. Something like belt slippage. This is to know if the compressor is fully locked up and its what causing the huge dip in RPM... If the compressor is locked the belt cannot possibly make it spin which should only allow it to make it slip the pulley.
 

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Discussion Starter · #12 ·
If you could try something like this:
Have someone near the engine bay (Hood Open) and make him/her listen to a specific change in sound when the compressor kicks in.. Something like belt slippage. This is to know if the compressor is fully locked up and its what causing the huge dip in RPM... If the compressor is locked the belt cannot possibly make it spin which should only allow it to make it slip the pulley.
Thank you Mr. Skirmich :29:

Most of the people in my family are unfortunately like me- learned helplessness/deer in headlights when it comes to anything mechanical...it would literally take any of us a full day if not longer, just to assemble a moderately challenging piece of IKEA furniture! :surprise:, but at the same time, we're all braniac-like when it comes to healthcare/medical fields....:nerd:

we'll let you know if I'm able to try your suggestion above, and then of course will follow-up after my service visit with either my independent Acura mechanic or the Acura stealership of choice- there are times like these when I don't mind letting the stealership do the work, albeit the high prices just for that extra peace of mind (that I know can be offered through at least one, single, relatively reliable, and least likely stealership to implement 'used car salesman-like sleazy service tactics all in the effort to inflate my cumulative service costs).

I'm really hoping that I don't have to replace the compressor as a quick online search suggests that the average stealership price for replacement of the AC compressor on a 2007-2013 Acura MDX ranges from about $1180 to about $1340- with the bulk of the charges coming from the actual labor fees.... :crying2:

Hopefully one of the related fluids is low, or a switch needs replacement....:|

Thanks again :29:
 
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