2005 Almost stalls at idle with A/C on and...

[Google]

when I have the blower on 2 setting or higher, I can feel a difference in the volume of airflow when idling where it's less.

The issue with A/C and idling has never occurred before today in my 10+ years of owing my Mazda3. Any thoughts?

Thanks

 

[concept]

Did you listen for any strange noises when the AC is on? A bad AC bearing or motor would draw higher current, possibly causing the idle to drop.
Also, if you have a service manual, see what raises the idle when the AC motor is energized. I'm not familiar with this but I'd imagine a switch or ECU component is responsible for raising the idle speed.

 

[BrianM3GS]

I don't notice anything with the fan, but I see noticeable variations in headlight intensity at near idle under some driving conditions. I think Mazda is playing with the voltage regulator behaviour to minimize load and reduce idle fuel consumption, but depending on load the available voltage can go too low.

Is the A/C really electrically driven? I would expect that only a hybrid, with high voltage hybrid system power available, would use an electric motor to drive the compressor. A/C compressors are normally belt-driven, with only a clutch (and of course the interior fan and possibly engine cooling fan) being electrically driven. The clutch power consumption shouldn't depend on how difficult it is to turn the compressor.

Very low system voltage could make the engine stumble, or at least interrupt instrument panel displays. My old Focus had a charging system problem and at times the dash would blank out (needles dropping to zero) while the engine kept running. Suddenly applying full load to the alternator could make an idling engine stumble.

Google, it sounds like you are seeing (hearing) a change in behaviour. I would be interested in suggestions about what could cause problems with charging system control.

 

[Google]

There were no strange noises at all except for last weekend. I use the A/C or defrost (which turns on the compressor) all the time. This was the first time this happened. I do find it interesting that the dealer always asked me if my A/C was on way back when I complained that the car would occasionally die without warning but that hasn't happened in over 8 years.

The only other thing which may or may not be related is I topped up my A/C coolant a bit (there are no leaks, oil color is fine) but I accidently filled it up a bit past the "max" indicator. I will use a turkey baster to remove some of the extra coolant, just in case.

If anything, perhaps my alternator might be going but aside from the blower fluctuation and that one time the engine almost stalled, there are no other symptoms.

 

[Google]

*bump*

I am now noticing a slight but not pure gasoline odour. It's not like pure gasoline, it's not the old style of unburned gasoline of cars with carburetors. But it's enough for me to have the windows closed when idling in traffic. My OBD reader doesn't give off any codes.

 

[5port]

Better get the car checked pronto. Could be a gas leak. When was the last time you replaced your battery. An old weak battery would cause a ton of problems.

 

[Google]

Better get the car checked pronto. Could be a gas leak. When was the last time you replaced your battery. An old weak battery would cause a ton of problems.

Thanks for the reply. My battery will be 2 years old in October. Start up is quite snappy, even after a few days or no driving.

I am due for servicing so I will let the dealer know. I think my car might be running a bit rich or the one of the fuel sensors might be a bit flaky.

 

[Google]

I checked today, this time with my tablet. And surprise surprise. Fault code P0661- Powertrain, Intake Manifold Tuning Valve Control Circuit Low (Bank 1).

Below is a detailed report from Torque Pro on some sensors. Not sure if there is anything else going on:

Test report:
------------------
MID:$f0 TID:$cc
Manufacturer defined MID -
Max: 0 Min: 8,273
Test result value: 52,464
FAIL
----
MID:$b0 TID:$99
-
Max: -74.38335% Min: 25.19731%
Test result value: -79.93798%
FAIL
----
MID:$b1 TID:$1a
Max: 2mV/s Min: 8,354mV/s
Test result value: 13,664mV/s
FAIL
----
MID:$01 TID:$01
Rich to Lean sensor threshold voltage(constant) - O2 Bank 1 Sensor 1
Max: 0.4492V Min: 0.4492V
Test result value: 0.4492V
PASS
----
MID:$01 TID:$02
Lean to Rich sensor threshold voltage(constant) - O2 Bank 1 Sensor 1
Max: 0.4492V Min: 0.4492V
Test result value: 0.4492V
PASS
----
MID:$01 TID:$03
Low sensor Voltage for switch time calculation - O2 Bank 1 Sensor 1
Max: 0.3516V Min: 0.3516V
Test result value: 0.3516V
PASS
----
MID:$01 TID:$04
High sensor Voltage for switch time calculation - O2 Bank 1 Sensor 1
Max: 0.55181V Min: 0.55181V
Test result value: 0.55181V
PASS
----
MID:$01 TID:$05
Rich to Lean sensor switch time(calculated) - O2 Bank 1 Sensor 1
Max: 320ms Min: 0ms
Test result value: 20ms
PASS
----
MID:$01 TID:$06
Lean to Rich sensor switch time(calculated) - O2 Bank 1 Sensor 1
Max: 400ms Min: 0ms
Test result value: 15ms
PASS
----
MID:$01 TID:$0a
Sensor period(calculated) - O2 Bank 1 Sensor 1
Max: 2,000ms Min: 0ms
Test result value: 420ms
PASS
----
MID:$02 TID:$03
Low sensor Voltage for switch time calculation - O2 Bank 1 Sensor 2
Max: 0.3V Min: 0.3V
Test result value: 0.3V
PASS
----
MID:$02 TID:$04
High sensor Voltage for switch time calculation - O2 Bank 1 Sensor 2
Max: 0.40004V Min: 0.40004V
Test result value: 0.40004V
PASS
----
MID:$02 TID:$05
Rich to Lean sensor switch time(calculated) - O2 Bank 1 Sensor 2
Max: 80ms Min: 0ms
Test result value: 15ms
PASS
----
MID:$21 TID:$80
- Catalyst Monitor Bank 1
Max: 255.99281Ratio Min: 1.49998Ratio
Test result value: 255.99281Ratio
PASS
----
MID:$31 TID:$83
- EGR Monitor Bank 1
Max: 655.34998kPa Min: 1.47kPa
Test result value: 7.96kPa
PASS
----
MID:$3a TID:$80
- EVAP Monitor (cap off)
Max: 255.99609mA Min: 1.90234mA
Test result value: 3.63281mA
PASS
----
MID:$3b TID:$80
- EVAP Monitor (0.090")
Max: 255.99609mA Min: 3.625mA
Test result value: 3.63281mA
PASS
----
MID:$3d TID:$80
- EVAP Monitor (0.020")
Max: 19.19141mA Min: 0mA
Test result value: 19.18359mA
PASS
----
MID:$a2 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 1 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a2 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 1 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a3 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 2 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a3 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 2 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a4 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 3 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a4 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 3 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a5 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 4 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a5 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 4 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$e1 TID:$80
Manufacturer defined MID -
Max: 37.99951Ratio Min: 0Ratio
Test result value: 11.51548Ratio
PASS
----
MID:$e1 TID:$81
Manufacturer defined MID -
Max: 6,553.5C Min: 111.2C
Test result value: 113.7C
PASS
----