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Help Engine shakes when the A/C is OFF !!

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Old 05-05-2016, 12:46 AM
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DevilsG37s
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Engine shakes when the A/C is OFF !!

Hey everyone,

I was searching through the net for a fix to my problem but with no luck.

Whenever the car idles with the air conditioning OFF, the whole engine start shaking every second or two. It's enough of a shake that the whole car shakes. One time before I notice the shaking the CEL came on with the code P0300 (Random/Multiple Cylinder Misfire Detected). After that I noticed the shaking though it might've been there before but the CEL got me to pay more attention untill I noticed it. So I reset the code after few daysand never showed any CEL light since. So I presumed that it's misfiring. I cleaned the MAF + the air filter + checked the spark plugs and they are clean. Been only 3 months since I replaced them. Ran a couple of tanks of some cleaning agents and have been running top octane gas since I got the car. Also did the ECU pedal reset and throttle position re-learn, still no luck.

The shake is accompanied with a knocking sound from under the car (Manual gearbox area). The shaking is occuring even when revving the car up to 2.5k RPM or so.

The only thing that stops it right now is turning the air conditioning ON, which smooths out the idle perfectly. I've seen tons of threads about this online, but nobody ever seems to answer back with what fixed the issue.

I have CNT hks Style test pipes installed + Z1 cold air intake with Apexi air filter heads + Z1 motor oil cooler and I was ECUTEK tuned but now I put back the stock tune to check if it's from the tune. But still the shaking is there.

As always, any help is appreciated.
Old 05-05-2016, 02:01 PM
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DevilsG37s
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150 views and not a single answer
Old 05-05-2016, 02:37 PM
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VQpoppa
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Vacuum leak or IACV (Idle Air Control Valve), dirty EGR..
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gimpy (05-05-2016)
Old 05-05-2016, 03:09 PM
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j50ny
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Originally Posted by DevilsG37s
150 views and not a single answer
Perhaps because folks may not know what the issue might be. OR....they could be hard at work and didn't have time to type out a long drawn-out response...like this one!! Lol

I've had, been around and worked on many cars that have had issues, but this is not a common one.

Have a feeling it's your throttle plate(s) or the entire body itself...although the plate will most likely be the culprit. With the electronic throttle, the pedal sends a signal ... blah blah blah and this in turn opens the throttle plate to allow more air in. If the plate gets stuck or something is bad with the signal, it won't open as much. Turn on the ac, the computer now sends an additional signal besides the one from your pedal to get the plate to open more. That would explain why it doesn't shake as much / misfire with the ac on.

Hope this helps. May not be what is taking place, but it's a good start
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Old 05-05-2016, 04:00 PM
  #5  
SonicVQ
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It is not your EGR. Our cars don't have EGR value. Our engines the valve overlap of the VVT for EGR.

You have a misfire issue. The A/C hides the problem because the fuel injector pulse width is INCREASED to compensate for the additional engine load. Since this adds a little extra fuel, the misfire/shaking goes away.

If you want to troubleshoot this your self, use a scan tool and have a look at 2 items:
(1) Fuel trim (short term & long term)
(2) Mode $06 misfire count

Post your results and we can continue to track this down.
If you don't have a scan tool/app that shows this, either get one or take it to a shop.

Last edited by SonicVQ; 05-05-2016 at 04:13 PM.
Old 05-05-2016, 05:05 PM
  #6  
DevilsG37s
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Originally Posted by VQpoppa
Vacuum leak or IACV (Idle Air Control Valve), dirty EGR..
Checked for any vacuum leaks and didn't find any. Is there a way to fix the IAC? like cleaning it or something?

Because after I installed the Z1 CAI and ran it for sometime, I did some PM check for the intake couple weeks ago and found plenty of dust in the inside of the intake tubing that I had to take apart all the pieces of the intake and clean them with soap and water until all clean with changing the heads to Apexi as Iv'e seen some filters comparison and Apexi was number one in both power and filtration.
Would this be the reason for this. Though Iv'e used 3M Fuel Tune-Up kit to clean all the system when I discovered the amount of the dust inside the tubing..Thanks to the dusty weather around here.

Originally Posted by j50ny
Perhaps because folks may not know what the issue might be. OR....they could be hard at work and didn't have time to type out a long drawn-out response...like this one!! Lol

I've had, been around and worked on many cars that have had issues, but this is not a common one.

Have a feeling it's your throttle plate(s) or the entire body itself...although the plate will most likely be the culprit. With the electronic throttle, the pedal sends a signal ... blah blah blah and this in turn opens the throttle plate to allow more air in. If the plate gets stuck or something is bad with the signal, it won't open as much. Turn on the ac, the computer now sends an additional signal besides the one from your pedal to get the plate to open more. That would explain why it doesn't shake as much / misfire with the ac on.

Hope this helps. May not be what is taking place, but it's a good start
Appreciate all the help from all the busy people that could shim in for any similar experience or info regarding this issue. And I thank them for their time.

You might be right but isn't revving the car to where it sits when the A/C on would stop the shaking. I tried that but still it shakes more noticeably up to 3K RPM due to the car smooths out when steadily revving the car above the idle RPM. But the shaking is still there.. it's like random shaking that shakes the whole car every few seconds like this --___--__-___-__--_-____-___--__---__-___
the dashes simulate the shakes in seconds and the underscore is when it's not shaking. It's just random.

The throttle response is instant and not stalling when quickly revving.. it's been cleaned about a week ago though it wasn't acting bad or anything. But still the shaking's there. I don't know about the T-bodies but I don't think they're the issue.

The car just got 40K mi on it and it's a 2012 Sedan 6MT

Originally Posted by SonicVQ
It is not your EGR. Our cars don't have EGR value. Our engines the valve overlap of the VVT for EGR.

You have a misfire issue. The A/C hides the problem because the fuel injector pulse width is INCREASED to compensate for the additional engine load. Since this adds a little extra fuel, the misfire/shaking goes away.

If you want to troubleshoot this your self, use a scan tool and have a look at 2 items:
(1) Fuel trim (short term & long term)
(2) Mode $06 misfire count

Post your results and we can continue to track this down.
If you don't have a scan tool/app that shows this, either get one or take it to a shop.
I have a Bluetooth scanner with the Torque app. No CEL or any error found. Hope I can find these two items. Will report back.

Thanks
Old 05-05-2016, 05:40 PM
  #7  
SonicVQ
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Originally Posted by VQpoppa
Vacuum leak or IACV (Idle Air Control Valve), dirty EGR..
Due to the VVEL, our engines don't have a IACV.
Old 05-05-2016, 05:51 PM
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SonicVQ
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The app Torque does not decode the "Test Results" or mode $06 data very well.

Post the results from Component ID (CID) $A2 to $A7 and Test ID (TID) $0B and $0C

This is the results of the mode $06 misfire counter. If you engine has been misfiring, it will tell us how often and which cylinder:
CID $A2 is cylinder 1, $A3 is cylinder 2.... $A7 is cylinder 6.


I just re-read the symptoms. A dirty MAF and under report at idle. Since you mention the dirt in the intake tubes, buy some MAF cleaner and remove/spray your MAFs. It could be as simple as that.
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Old 05-05-2016, 06:04 PM
  #9  
DevilsG37s
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Originally Posted by SonicVQ
The app Torque does not decode the "Test Results" or mode $06 data very well.

Post the results from Component ID (CID) $A2 to $A7 and Test ID (TID) $0B and $0C

This is the results of the mode $06 misfire counter. If you engine has been misfiring, it will tell us how often and which cylinder:
CID $A2 is cylinder 1, $A3 is cylinder 2.... $A7 is cylinder 6.


I just re-read the symptoms. A dirty MAF and under report at idle. Since you mention the dirt in the intake tubes, buy some MAF cleaner and remove/spray your MAFs. It could be as simple as that.
I cleaned both MAFs with a MAF cleaner thoroughly the same time when I cleaned the intake parts. The idle is smooth but it gets rough only when there is a shake it's then instantly drop a tiny amount and comes back.

Would Torque have all these CID and TID items you mentioned?
Old 05-05-2016, 06:06 PM
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DevilsG37s
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I'm kinda noob when using Torque but I'll dig into it till I get you some useful info.
Don't mind a little help in how to get those info
Old 05-05-2016, 06:16 PM
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DevilsG37s
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Would a defective or a dirty AFR upstream O2 sensor make these symptoms?
I'm just trying to put out everything in mind.
Old 05-05-2016, 06:18 PM
  #12  
SonicVQ
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Torque has them, let me show you

(1) connect OBD scanner to OBD2 port
(2) connect to android device to OBD scanner (either bluetooth or wifi)
(3) start Torque
(4) Touch "Test Results" (this is the mode $06 test results)
(5) Look for CID $A2-$A7 and TID $0B-$0C
(6) Report results

In the next while, I will make a video showing how to do this and what it means.
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Old 05-05-2016, 06:23 PM
  #13  
DevilsG37s
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Originally Posted by SonicVQ
Torque has them, let me show you

(1) connect OBD scanner to OBD2 port
(2) connect to android device to OBD scanner (either bluetooth or wifi)
(3) start Torque
(4) Touch "Test Results" (this is the mode $06 test results)
(5) Look for CID $A2-$A7 and TID $0B-$0C
(6) Report results

In the next while, I will make a video showing how to do this and what it means.
Sounds easy.. Will report back soon.
Old 05-05-2016, 07:13 PM
  #14  
DevilsG37s
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Well, SonicVQ..you're the man

It's clearly the 6th Cylinder is misfiring like hell. Here are the logs:

Test report:
------------------
MID:$01 TID:$83
- O2 Bank 1 Sensor 1
Max: 65.535V Min: 0.4V
Test result value: 2.14V
PASS
----
MID:$01 TID:$84
- O2 Bank 1 Sensor 1
Max: 4.399V Min: 0V
Test result value: 2.14V
PASS
----
MID:$01 TID:$85
- O2 Bank 1 Sensor 1
Max: 2.149V Min: 0V
Test result value: 2.07V
PASS
----
MID:$01 TID:$86
- O2 Bank 1 Sensor 1
Max: 65.535V Min: 2.25V
Test result value: 5.065V
PASS
----
MID:$01 TID:$87
- O2 Bank 1 Sensor 1
Max: 65.535 Min: 0.3
Test result value: 0.558
PASS
----
MID:$01 TID:$88
- O2 Bank 1 Sensor 1
Max: 65.535 Min: 0.3
Test result value: 0.48
PASS
----
MID:$01 TID:$89
- O2 Bank 1 Sensor 1
Max: 0.449 Min: -32.768
Test result value: -0.04
PASS
----
MID:$02 TID:$07
Minimum sensor Voltage for test cycle(calculated) - O2 Bank 1 Sensor 2
Max: 0.17V Min: 0V
Test result value: 0.17V
PASS
----
MID:$02 TID:$08
Maximum sensor Voltage for test cycle(calculated) - O2 Bank 1 Sensor 2
Max: 2.55V Min: 0.7V
Test result value: 0.7V
PASS
----
MID:$02 TID:$80
- O2 Bank 1 Sensor 2
Max: 1.19V Min: 0V
Test result value: 0.2V
PASS
----
MID:$02 TID:$81
- O2 Bank 1 Sensor 2
Max: 2.55V Min: 0.48V
Test result value: 0.6V
PASS
----
MID:$02 TID:$82
- O2 Bank 1 Sensor 2
Max: 3.9S Min: 0S
Test result value: 0.4S
PASS
----
MID:$05 TID:$83
- O2 Bank 2 Sensor 1
Max: 65.535V Min: 0.4V
Test result value: 2.085V
PASS
----
MID:$05 TID:$84
- O2 Bank 2 Sensor 1
Max: 4.399V Min: 0V
Test result value: 2.085V
PASS
----
MID:$05 TID:$85
- O2 Bank 2 Sensor 1
Max: 2.149V Min: 0V
Test result value: 2.04V
PASS
----
MID:$05 TID:$86
- O2 Bank 2 Sensor 1
Max: 65.535V Min: 2.25V
Test result value: 5.065V
PASS
----
MID:$05 TID:$87
- O2 Bank 2 Sensor 1
Max: 65.535 Min: 0.3
Test result value: 0.694
PASS
----
MID:$05 TID:$88
- O2 Bank 2 Sensor 1
Max: 65.535 Min: 0.3
Test result value: 0.594
PASS
----
MID:$05 TID:$89
- O2 Bank 2 Sensor 1
Max: 0.449 Min: -32.768
Test result value: 0.17
PASS
----
MID:$06 TID:$07
Minimum sensor Voltage for test cycle(calculated) - O2 Bank 2 Sensor 2
Max: 0.17V Min: 0V
Test result value: 0.16V
PASS
----
MID:$06 TID:$08
Maximum sensor Voltage for test cycle(calculated) - O2 Bank 2 Sensor 2
Max: 2.55V Min: 0.7V
Test result value: 0.7V
PASS
----
MID:$06 TID:$80
- O2 Bank 2 Sensor 2
Max: 1.19V Min: 0V
Test result value: 0.67V
PASS
----
MID:$06 TID:$81
- O2 Bank 2 Sensor 2
Max: 2.55V Min: 0.48V
Test result value: 0.48V
PASS
----
MID:$06 TID:$82
- O2 Bank 2 Sensor 2
Max: 3.9S Min: 0S
Test result value: 2.3S
PASS
----
MID:$21 TID:$80
- Catalyst Monitor Bank 1
Test incomplete or dependant test failed
--
MID:$21 TID:$82
- Catalyst Monitor Bank 1
Test incomplete or dependant test failed
--
MID:$22 TID:$80
- Catalyst Monitor Bank 2
Test incomplete or dependant test failed
--
MID:$22 TID:$82
- Catalyst Monitor Bank 2
Test incomplete or dependant test failed
--
MID:$35 TID:$80
-
Max: 13° Min: -13°
Test result value: 2.5°
PASS
----
MID:$35 TID:$82
-
Max: 13° Min: -13°
Test result value: 1°
PASS
----
MID:$35 TID:$84
-
Max: 499ms Min: 0ms
Test result value: 109ms
PASS
----
MID:$35 TID:$85
-
Max: 10,779ms Min: 0ms
Test result value: 10ms
PASS
----
MID:$36 TID:$80
-
Max: 13° Min: -13°
Test result value: 4.5°
PASS
----
MID:$36 TID:$82
-
Max: 13° Min: -13°
Test result value: 0°
PASS
----
MID:$36 TID:$84
-
Max: 499ms Min: 0ms
Test result value: 107ms
PASS
----
MID:$36 TID:$85
-
Max: 2,379ms Min: 0ms
Test result value: 20ms
PASS
----
MID:$3c TID:$81
- EVAP Monitor (0.040")
Max: 32.767kPa Min: 0.43kPa
Test result value: 32.767kPa
PASS
----
MID:$3c TID:$82
- EVAP Monitor (0.040")
Max: 32.767kPa Min: 0.1kPa
Test result value: 32.767kPa
PASS
----
MID:$3d TID:$83
- EVAP Monitor (0.020")
Max: 655.34998V Min: 0.02V
Test result value: 0.03V
PASS
----
MID:$41 TID:$81
- O2 Heater Monitor Bank 1 - Sensor 1
Max: 4.779V Min: 0.39V
Test result value: 1.205V
PASS
----
MID:$42 TID:$80
- O2 Heater Monitor Bank 1 - Sensor 2
Max: 4.71V Min: 0.24V
Test result value: 1.58V
PASS
----
MID:$45 TID:$81
- O2 Heater Monitor Bank 2 - Sensor 1
Max: 4.779V Min: 0.39V
Test result value: 1.195V
PASS
----
MID:$46 TID:$80
- O2 Heater Monitor Bank 2 - Sensor 2
Max: 4.71V Min: 0.24V
Test result value: 1.44V
PASS
----
MID:$81 TID:$80
- Fuel System Monitor Bank 1
Test incomplete or dependant test failed
--
MID:$81 TID:$81
- Fuel System Monitor Bank 1
Test incomplete or dependant test failed
--
MID:$82 TID:$80
- Fuel System Monitor Bank 2
Test incomplete or dependant test failed
--
MID:$82 TID:$81
- Fuel System Monitor Bank 2
Test incomplete or dependant test failed
--
MID:$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:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 3 Data
Max: 65,535Count Min: 0Count
Test result value: 2Count
PASS
----
MID:$a4 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 3 Data
Max: 65,535Count Min: 0Count
Test result value: 1Count
PASS
----
MID:$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:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 4 Data
Max: 65,535Count Min: 0Count
Test result value: 0Count
PASS
----
MID:$a6 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 5 Data
Max: 65,535Count Min: 0Count
Test result value: 2Count
PASS
----
MID:$a6 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 5 Data
Max: 65,535Count Min: 0Count
Test result value: 3Count
PASS
----
MID:$a7 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 6 Data
Max: 65,535Count Min: 0Count
Test result value: 15Count
PASS
----
MID:$a7 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 6 Data
Max: 65,535Count Min: 0Count
Test result value: 213Count
PASS
----
End of report.
Old 05-05-2016, 07:16 PM
  #15  
DevilsG37s
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I'm wondering what's the cause of all these misfiring events in 3rd, 5th and 6th cylinders.


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